Lunar Landing Walking Simulator: Researchers at Langley study the ability of astronauts to walk, run and perform other tasks required during lunar exploration. The Reduced Gravity Simulator gave researchers the opportunity to look at the effects of one-sixth normal gravity on self-locomotion. Several Apollo astronauts practiced lunar waling at the facility.

STS006-10-417 (7 April 1983) --- Astronauts F. Story Musgrave, left, and Donald H. Peterson float about in the cargo bay of the Earth-orbiting space shuttle Challenger during their April 7, 1983, extravehicular activity (EVA). Their "floating about" is restricted via tethers to safety slide wires. Thanks to the tether/slide wire combination, Peterson is able to translate along the port side hand rails. Musgrave is near the Airborne Support Equipment (ASE) for the now vacated Inertial Upper Stage (IUS). Clouds can be seen in the background. Photo credit: NASA

A locomotive backs into Building 112 as it prepares to hitch up with the railcar that will transport the Soyuz TMA-03M to the launch pad at the Baikonur Cosmodrome in Kazakhstan, Monday, Dec. 19, 2011. The launch of the Soyuz spacecraft with Expedition 30 Soyuz Commander Oleg Kononenko of Russia, NASA Flight Engineer Don Pettit and ESA (European Space Agency) astronaut and Flight Engineer Andre Kuipers is scheduled for 7:16 p.m. local time on Wednesday, December 21. Photo Credit (NASA/Carla Cioffi)

A locomotive engineer waits in advance of the Soyuz rocket being rolled out by train to the launch pad at Site 31, Tuesday, April 6, 2021, at the Baikonur Cosmodrome in Kazakhstan. Expedition 65 NASA astronaut Mark Vande Hei, Roscosmos cosmonauts Pyotr Dubrov and Oleg Novitskiy are scheduled to launch aboard their Soyuz MS-18 spacecraft on April 9. Photo Credit: (NASA/Bill Ingalls)

Astronaut Roger Chaffee on the Reduced Gravity Walking Simulator located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. A.W. Vigil, described the simulator as follows: "When the astronauts land on the moon they will be in an unfamiliar environment involving, particularly, a gravitational field only one-sixth as strong as on earth. A novel method of simulating lunar gravity has been developed and is supported by a puppet-type suspension system at the end of a long pendulum. A floor is provided at the proper angle so that one-sixth of the subject's weight is supported by the floor with the remainder being supported by the suspension system. This simulator allows almost complete freedom in vertical translation and pitch and is considered to be a very realistic simulation of the lunar walking problem. For this problem this simulator suffers only slightly from the restrictions in lateral movement it puts on the test subject. This is not considered a strong disadvantage for ordinary walking problems since most of the motions do, in fact, occur in the vertical plane. However, this simulation technique would be severely restrictive if applied to the study of the extra-vehicular locomotion problem, for example, because in this situation complete six degrees of freedom are rather necessary. This technique, in effect, automatically introduces a two-axis attitude stabilization system into the problem. The technique could, however, be used in preliminary studies of extra-vehicular locomotion where, for example, it might be assumed that one axis of the attitude control system on the astronaut maneuvering unit may have failed." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308, p. 377; A.W. Vigil, "Discussion of Existing and Planned Simulators for Space Research," Paper presented at Conference on the Role of Simulation in Space Technology," Blacksburg, VA, August 17-21, 1964.

Astronaut Walt Cunningham on the Reduced Gravity Walking Simulator located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. A.W. Vigil described the purpose of the simulator in his paper "Discussion of Existing and Planned Simulators for Space Research," "When the astronauts land on the moon they will be in an unfamiliar environment involving, particularly, a gravitational field only one-sixth as strong as on earth. A novel method of simulating lunar gravity has been developed and is supported by a puppet-type suspension system at the end of a long pendulum. A floor is provided at the proper angle so that one-sixth of the subject's weight is supported by the floor with the remainder being supported by the suspension system. This simulator allows almost complete freedom in vertical translation and pitch and is considered to be a very realistic simulation of the lunar walking problem. For this problem this simulator suffers only slightly from the restrictions in lateral movement it puts on the test subject. This is not considered a strong disadvantage for ordinary walking problems since most of the motions do, in fact, occur in the vertical plane. However, this simulation technique would be severely restrictive if applied to the study of the extra-vehicular locomotion problem, for example, because in this situation complete six degrees of freedom are rather necessary. This technique, in effect, automatically introduces a two-axis attitude stabilization system into the problem. The technique could, however, be used in preliminary studies of extra-vehicular locomotion where, for example, it might be assumed that one axis of the attitude control system on the astronaut maneuvering unit may have failed." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995), p. 377; A.W. Vigil, "Discussion of Existing and Planned Simulators for Space Research," Paper presented at Conference on the Role of Simulation in Space Technology," Blacksburg, VA, August 17-21, 1964.

Reduced Gravity Walking Simulator located in the hangar at Langley Research Center. The initial version of this simulator was located inside the hangar. Later a larger version would be located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. A.W. Vigil wrote in his paper Discussion of Existing and Planned Simulators for Space Research, When the astronauts land on the moon they will be in an unfamiliar environment involving, particularly, a gravitational field only one-sixth as strong as on earth. A novel method of simulating lunar gravity has been developed and is supported by a puppet-type suspension system at the end of a long pendulum. A floor is provided at the proper angle so that one-sixth of the subject' s weight is supported by the floor with the remainder being supported by the suspension system. This simulator allows almost complete freedom in vertical translation and pitch and is considered to be a very realistic simulation of the lunar walking problem. For this problem this simulator suffers only slightly from the restrictions in lateral movement it puts on the test subject. This is not considered a strong disadvantage for ordinary walking problems since most of the motions do, in fact, occur in the vertical plane. However, this simulation technique would be severely restrictive if applied to the study of the extra-vehicular locomotion problem, for example, because in this situation complete six degrees of freedom are rather necessary. This technique, in effect, automatically introduces a two-axis attitude stabilization system into the problem. The technique could, however, be used in preliminary studies of extra-vehicular locomotion where, for example, it might be assumed that one axis of the attitude control system on the astronaut maneuvering unit may have failed. -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308, p. 377 A.W. Vigil, Discussion of Existing and Planned Simulators for Space Research, Paper presented at Conference on the Role of Simulation in Space Technology, Blacksburg, VA, August 17-21, 1964.

Special "space" suit for the Reduced Gravity Walking Simulator located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. A.W. Vigil described the purpose of the simulator in his paper "Discussion of Existing and Planned Simulators for Space Research," "When the astronauts land on the moon they will be in an unfamiliar environment involving, particularly, a gravitational field only one-sixth as strong as on earth. A novel method of simulating lunar gravity has been developed and is supported by a puppet-type suspension system at the end of a long pendulum. A floor is provided at the proper angle so that one-sixth of the subject's weight is supported by the floor with the remainder being supported by the suspension system. This simulator allows almost complete freedom in vertical translation and pitch and is considered to be a very realistic simulation of the lunar walking problem. For this problem this simulator suffers only slightly from the restrictions in lateral movement it puts on the test subject. This is not considered a strong disadvantage for ordinary walking problems since most of the motions do, in fact, occur in the vertical plane. However, this simulation technique would be severely restrictive if applied to the study of the extra-vehicular locomotion problem, for example, because in this situation complete six degrees of freedom are rather necessary. This technique, in effect, automatically introduces a two-axis attitude stabilization system into the problem. The technique could, however, be used in preliminary studies of extra-vehicular locomotion where, for example, it might be assumed that one axis of the attitude control system on the astronaut maneuvering unit may have failed." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995), p. 377; A.W. Vigil, "Discussion of Existing and Planned Simulators for Space Research," Paper presented at Conference on the Role of Simulation in Space Technology," Blacksburg, VA, August 17-21, 1964.

Cable system which supports the test subject on the Reduced Gravity Walking Simulator. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. A.W. Vigil described the purpose of the simulator as follows: "When the astronauts land on the moon they will be in an unfamiliar environment involving, particularly, a gravitational field only one-sixth as strong as on earth. A novel method of simulating lunar gravity has been developed and is supported by a puppet-type suspension system at the end of a long pendulum. A floor is provided at the proper angle so that one-sixth of the subject's weight is supported by the floor with the remainder being supported by the suspension system. This simulator allows almost complete freedom in vertical translation and pitch and is considered to be a very realistic simulation of the lunar walking problem. For this problem this simulator suffers only slightly from the restrictions in lateral movement it puts on the test subject. This is not considered a strong disadvantage for ordinary walking problems since most of the motions do, in fact, occur in the vertical plane. However, this simulation technique would be severely restrictive if applied to the study of the extra-vehicular locomotion problem, for example, because in this situation complete six degrees of freedom are rather necessary. This technique, in effect, automatically introduces a two-axis attitude stabilization system into the problem. The technique could, however, be used in preliminary studies of extra-vehicular locomotion where, for example, it might be assumed that one axis of the attitude control system on the astronaut maneuvering unit may have failed." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995); A.W. Vigil, "Discussion of Existing and Planned Simulators for Space Research," Paper presented at Conference on the Role of Simulation in Space Technology," Blacksburg, VA, August 17-21, 1964.

Test subject wearing the pressurized "space" suit for the Reduced Gravity Walking Simulator located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. A.W. Vigil described the purpose of the simulator in his paper "Discussion of Existing and Planned Simulators for Space Research," "When the astronauts land on the moon they will be in an unfamiliar environment involving, particularly, a gravitational field only one-sixth as strong as on earth. A novel method of simulating lunar gravity has been developed and is supported by a puppet-type suspension system at the end of a long pendulum. A floor is provided at the proper angle so that one-sixth of the subject's weight is supported by the floor with the remainder being supported by the suspension system. This simulator allows almost complete freedom in vertical translation and pitch and is considered to be a very realistic simulation of the lunar walking problem. For this problem this simulator suffers only slightly from the restrictions in lateral movement it puts on the test subject. This is not considered a strong disadvantage for ordinary walking problems since most of the motions do, in fact, occur in the vertical plane. However, this simulation technique would be severely restrictive if applied to the study of the extra-vehicular locomotion problem, for example, because in this situation complete six degrees of freedom are rather necessary. This technique, in effect, automatically introduces a two-axis attitude stabilization system into the problem. The technique could, however, be used in preliminary studies of extra-vehicular locomotion where, for example, it might be assumed that one axis of the attitude control system on the astronaut maneuvering unit may have failed." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995), p. 377; A.W. Vigil, "Discussion of Existing and Planned Simulators for Space Research," Paper presented at Conference on the Role of Simulation in Space Technology," Blacksburg, VA, August 17-21, 1964.

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 has been undergoing modifications inside high bay 2 of the Vehicle Assembly Building in preparation to carry the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, a space shuttle era mobile launcher platform, on the left, sits on pedestals outside the Vehicle Assembly Building. To the right is the mobile launcher that will support the space agency's Space Launch System heavy-lift rocket and Orion spacecraft. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 is parked outside of the Vehicle Assembly Building. The Crawler-transporter has been undergoing modifications to ensure its ability to carry the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Ben Smegelsky

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, the mobile launcher is being prepared to support the space agency's Space Launch System heavy-lift rocket and Orion spacecraft. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the crawler way toward Launch Pad 39A following modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida the mobile launcher is being prepared to support the space agency's Space Launch System heavy-lift rocket and Orion spacecraft. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Ben Smegelsky

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Dimitri Gerondidakis

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 arrives at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Ben Smegelsky

A "suited" test subject on the Reduced Gravity Walking Simulator located in the hangar at Langley Research Center. The initial version of this simulator was located inside the hangar. Later a larger version would be located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. Francis B. Smith wrote in "Simulators For Manned Space Research:" "The cables which support the astronaut are supported by an overhead trolley about 150 feet above the center line of the walkway and the support is arranged so that the subject is free to walk, run, jump, and perform other self-locomotive tasks in a more-or-less normal manner, even though he is constrained to move in one place." "The studies thus far show that an astronaut should have no particular difficulty in walking in a pressurized space suit on a hard lunar surface. Rather, the pace was faster and the suit was found to be more comfortable and less fatiguing under lunar "g" than under earth "g." When the test subject wished to travel hurriedly any appreciable distance, a long loping gait at about 10 feet per second was found to be most comfortable." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, (Washington: NASA, 1995), p. 377; Francis B. Smith, "Simulators For Manned Space Research," Paper for 1966 IEEE International Convention, New York, NY, March 21-25, 1966.

CAPE CANAVERAL, Fla. -- Viewed from the Launch Pad 39A flame trench, crawler-transporter No. 2 moves under a space shuttle era mobile launcher platform at NASA's Kennedy Space Center in Florida. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building where it has been undergoing modifications. The test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves away from the Vehicle Assembly Building where it has been undergoing modifications. The test dive is designed to check out modifications to ensure its ability to carry the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the gravel crawler way. The crawler-transporter is undergoing testing at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the gravel crawler way. The crawler-transporter is undergoing testing at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building where it has been undergoing modifications. The test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, a technician uses instrumentation to ensure accuracy as crawler-transporter No. 2 moves a space shuttle era mobile launcher platform into position for placement at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, a technician monitors operations as crawler-transporter No. 2 moves a space shuttle era mobile launcher platform over a support pedestal at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the gravel crawler way after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform down the gravel crawler way at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns to its park site after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- Viewed from under a space shuttle era mobile launcher platform on Launch Pad 39A at NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 approaches. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform on Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- Technicians monitor progress as crawler-transporter No. 2 lifts a space shuttle era mobile launcher platform at Launch Pad 39A at NASA's Kennedy Space Center in Florida. The crawler-transporter is undergoing testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, technicians use instrumentation to ensure accuracy as crawler-transporter No. 2 moves a space shuttle era mobile launcher platform into position for placement at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the gravel crawler way after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 has been undergoing modifications in high bay 2 of the Vehicle Assembly Building. It has been undergoing a test drive checking out modifications to ensure its ability to carry the space agency's Space Launch System heavy-lift rocket to the launch pad. In the background is the mobile launcher being prepared to support launch vehicles such as space agency's the Space Launch System heavy-lift rocket and Orion spacecraft. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- As crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida, technicians keep watch. The crawler-transporter test drive is designed to check out recent modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- Viewed from the Launch Pad 39A flame trench, crawler-transporter No. 2 moves under a space shuttle era mobile launcher platform at NASA's Kennedy Space Center in Florida. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- A truck sprays water on the gravel crawler way at NASA's Kennedy Space Center in Florida as crawler-transporter No. 2 moves toward Launch Pad 39A. With crawler-transporter modifications complete, the test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 has been undergoing modifications in high bay 2 of the Vehicle Assembly Building. It has been undergoing a test drive checking out modifications to ensure its ability to carry launch vehicles to the launch pad. In the background is the mobile launcher being prepared to support the space agency's Space Launch System heavy-lift rocket and Orion spacecraft. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- Bill Couch, standing on the left, and Gary Milbourne, both of United Space Alliance monitor the updated controls of crawler-transporter No. 2 as it moves out of high bay 2 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. The test drive is designed to check out recent modifications and upgrades to ensure its capability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- Viewed from above the flame trench at Launch Pad 39A at NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves away from the Vehicle Assembly Building where it has been undergoing modifications. The test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves past the Vehicle Assembly Building where it has been undergoing modifications. The test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the gravel crawler way after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, a tractor levels out the gravel after the six-million-pound crawler-transporter passed by on its way from the Vehicle Assembly Building to Launch Pad 39A. The test drive is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Ben Smegelsky

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns to its park site after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- Technicians monitor progress as crawler-transporter No. 2 moves along the gravel crawler way at NASA's Kennedy Space Center in Florida. The crawler-transporter is undergoing testing at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, a technician monitors operations as crawler-transporter No. 2 moves a space shuttle era mobile launcher platform over a support pedestal at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns to the Vehicle Assembly Building after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- Viewed from under a space shuttle era mobile launcher platform on Launch Pad 39A at NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves under. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- Technicians keep watch as crawler-transporter No. 2 moves along the crawler way at NASA's Kennedy Space Center in Florida. The crawler-transporter test dive is designed to check out recent modifications to ensure its ability to carry the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- A space shuttle era mobile launcher platform remains on Launch Pad 39A at NASA's Kennedy Space Center in Florida. It will be moved by crawler-transporter No. 2 as part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building where it has been undergoing modifications. The test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns to its park site after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves under a space shuttle era mobile launcher platform on Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- United Space Alliance Project Manager Mike Parrish sits in the driver's position of crawler-transporter No. 2 which has been undergoing modifications inside high bay 2 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida. The upgrades are designed to ensure the crawler-transporter can carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- A truck sprays water on the gravel crawler way at NASA's Kennedy Space Center in Florida as crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building. With crawler-transporter modifications complete, the test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns to the Vehicle Assembly Building after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- A truck sprays water on the gravel crawler way at NASA's Kennedy Space Center in Florida as crawler-transporter No. 2 is undergoing testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- Viewed from under a space shuttle era mobile launcher platform on Launch Pad 39A at NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves under. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves up the gravel crawler way at Launch Pad 39A. The crawler-transporter is undergoing testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- Viewed from under a space shuttle era mobile launcher platform on Launch Pad 39A at NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves under. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns to its park site after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- The team that has been modifying crawler-transporter No. 2 inside high bay 2 of the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida gathered prior to a test drive. The crawler-transporter has been undergoing modifications in preparation to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves along the gravel crawler way. The crawler-transporter is undergoing testing at Launch Pad 39A to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- Florida's Lt. Gov. Jennifer Carroll, left, and NASA Commercial Crew Program Manager Ed Mango shake hands at the National Space Club Florida Committee's August luncheon at the Radisson Resort at the Port in Cape Canaveral, Fla. Mango was the event's guest speaker, discussing the innovative steps the agency is taking with industry partners to develop the next U.S. space transportation capability to and from low Earth orbit, which will eventually be available for use by the U.S. government and other commercial customers. To learn more about the Commercial Crew Program, visit www.nasa.gov/commercialcrew. Photo credit: Kim Shiflett NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- A truck sprays water on the gravel crawler way at NASA's Kennedy Space Center in Florida as crawler-transporter No. 2 completes testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building where it has been undergoing modifications. The test dive is designed to check out modifications to ensure its ability to carry the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves up the gravel crawler way at Launch Pad 39A. The crawler-transporter is undergoing testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 returns toits park site after completion of testing at Launch Pad 39A. The activity is designed to check out recently completed modifications to ensure the crawler-transporter's ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Frankie Martin

CAPE CANAVERAL, Fla. -- A truck sprays water on the gravel crawler way at NASA's Kennedy Space Center in Florida as crawler-transporter No. 2 moves out of high bay 2 of the Vehicle Assembly Building. With crawler-transporter modifications complete, the test drive is designed to check out modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the launch pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each the size of a baseball infield and powered by locomotive and large electrical power generator engines, the crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles projects to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Jim Grossmann

CAPE CANAVERAL, Fla. -- In this wide-angle, panoramic view, crawler-transporter No. 2 is undergoing testing at Launch Pad 39A at NASA's Kennedy Space Center in Florida. The activity is designed to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/ Jim Grossmann

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, crawler-transporter No. 2 moves a space shuttle era mobile launcher platform down the gravel crawler way at Launch Pad 39A. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

CAPE CANAVERAL, Fla. -- A technician monitors operations as crawler-transporter No. 2 moves a space shuttle era mobile launcher platform down the gravel crawler way at Launch Pad 39A at NASA's Kennedy Space Center in Florida. The activity was part of testing to check out recently completed modifications to ensure its ability to carry launch vehicles such as the space agency's Space Launch System heavy-lift rocket to the pad. NASA's Ground Systems Development and Operations Program is leading the 20-year life-extension project for the crawler. A pair of behemoth machines called crawler-transporters has carried the load of taking rockets and spacecraft to the launch pad for more than 40 years at NASA’s Kennedy Space Center in Florida. Each weighing six and a half million pounds and larger in size than a professional baseball infield, the crawler-transporters are powered by locomotive and large electrical power generator engines. The crawler-transporters will stand ready to keep up the work for the next generation of launch vehicles to lift astronauts into space. For more information, visit http://www.nasa.gov/exploration/systems/ground/index.html Photo credit: NASA/Cory Huston

A test subject being suited up for studies on the Reduced Gravity Walking Simulator located in the hangar at Langley Research Center. The initial version of this simulator was located inside the hangar. Later a larger version would be located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. Francis B. Smith wrote in his paper "Simulators For Manned Space Research," "I would like to conclude this talk with a discussion of a device for simulating lunar gravity which is very effective and yet which is so simple that its cost is in the order of a few thousand dollars at most, rather than hundreds of thousands. With a little ingenuity, one could almost build this type simulator in his backyard for children to play on. The principle is ...if a test subject is suspended in a sling so that his body axis makes an angle of 9 1/2 degrees with the horizontal and if he then "stands" on a platform perpendicular to his body axis, the component of the earth's gravity forcing him toward the platform is one times the sine of 9 1/2 degrees or approximately 1/6 of the earth's normal gravity field. That is, a 180 pound astronaut "standing" on the platform would exert a force of only 30 pounds - the same as if he were standing upright on the lunar surface." -- Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308; Francis B. Smith, "Simulators For Manned Space Research," Paper for 1966 IEEE International Convention, New York, NY, March 21-25, 1966