Vestibular Study testing in Zero-G flights on the KC-135. Seen in this view are Roberta Bonder and others experiencing weightlessness.

S79-28602 (2 March 1979) --- Astronaut candidate Guion S. Bluford and Aviation Safety Officer Charles F. Hayes got a unique perspective of their environment during a zero gravity flight. They are aboard a KC-135 aircraft, which flies a special pattern repeatedly to afford a series of 30-seconds-of-weightlessness sessions. Bluford and Hayes are being assisted by C. P. Stanley of the photography branch of the photographic technology division at Johnson Space Center (JSC). Some medical studies and a motion sickness experiment were conducted on this particular flight. Bluford is one of 20 scientist-astronaut candidates who began training at JSC in July of 1978. Photo credit: NASA

S86-25191 (for release January 1986) --- The two representatives of the Teacher-in-Space Project continue their training program at the Johnson Space Center with an additional flight aboard NASA?s KC-135 ?zero gravity? aircraft. Sharon Christa McAuliffe, left, is prime crew payload specialist, and Barbara R. Morgan is in training as backup payload specialist. The photo was taken by Keith Meyers of New York Times. Photo credit: NASA

S86-25196 (January 1986) --- Sharon Christa McAuliffe, STS-51L citizen observer/payload specialist, gets a preview of microgravity during a special flight aboard NASA?s KC-135 ?zero gravity? aircraft. McAuliffe will represent the Teacher-in-Space Project aboard the space shuttle Challenger when it launches later this month. This photograph was taken by Keith Meyers of the New York Times. EDITOR?S NOTE: The STS-51L crew members lost their lives in the space shuttle Challenger accident moments after launch on Jan. 28, 1986 from the Kennedy Space Center (KSC). Photo credit: NASA

KENNEDY SPACE CENTER, FLA. -- Peter Diamandis (left), founder of the Zero Gravity Corp., and noted physicist Stephen Hawking move away from Zero G's modified Boeing 727 on the runway at the Kennedy Space Center's Shuttle Landing Facility. Hawking enjoyed his first zero gravity flight provided by Zero G. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, noted physicist Stephen Hawking, in the wheelchair, is ready to get onboard a modified Boeing 727 aircraft owned by Zero Gravity Corp. for his first zero-gravity flight. Zero Gravity Corp. is a commercial company licensed to provide the public with weightless flight experiences. At right is Peter Diamandis, founder of the Zero Gravity Corp. Behind Hawking is Nicola O'Brien, a nurse practitioner who is Hawking's aide. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

ZERO GRAVITY AIRCRAFT KC135 FLIGHTS AT LEWIS RESEARCH CENTER

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, noted physicist Stephen Hawking, in the wheelchair, arrives at the runway for his first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. At left is Peter Diamandis, founder of the Zero Gravity Corp. At center is Nicola O'Brien, a nurse practitioner who is Hawking's aide. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, noted physicist Stephen Hawking, in the wheelchair, arrives at the runway for his first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. At left is Peter Diamandis, founder of the Zero Gravity Corp. At center is Nicola O'Brien, a nurse practitioner who is Hawking's aide. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, Space Florida president Steve Kohler (left) talks to the media about physicist Stephen Hawking's (in the wheelchair) first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. At right is Peter Diamandis, founder of the Zero Gravity Corp. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- The media surround noted wheelchair-bound physicist Stephen Hawking after his arrival at the Kennedy Space Center Shuttle Landing Facility for his first zero-gravity flight. Behind Hawking, at left, is Space Florida president Steve Kohler. In the center, striding toward Hawking, is Zero Gravity Corp. founder Peter Diamandis. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity, a commercial company licensed to provide the public with weightless flight experiences. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, Peter Diamandis, founder of the Zero Gravity Corp., talks to the media about physicist Stephen Hawking's (in the wheelchair) first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- The media surround noted wheelchair-bound physicist Stephen Hawking after his arrival at the Kennedy Space Center Shuttle Landing Facility for his first zero-gravity flight. Behind Hawking, at left, are Zero Gravity Corporation founder Peter Diamandis and Space Florida president Steve Kohler. The flight will be aboard a modified Boeing 727 aircraft owned by Zero G, a commercial company licensed to provide the public with weightless flight experiences. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, noted physicist Stephen Hawking, in the wheelchair, arrives at the runway for his first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. At left is Peter Diamandis, founder of the Zero Gravity Corp. Behind Hawking is Nicola O'Brien, a nurse practitioner who is Hawking's aide. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Noted physicist Stephen Hawking (center) returns to the Kennedy Space Center Shuttle Landing Facility after a zero gravity flight. At far left is Peter Diamandis, founder of the Zero Gravity Corp. that provided the flight aboard its modified Boeing 727. Hawking suffers from amyotrophic lateral sclerosis (also known as Lou Gehrig's disease). At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, a modified Boeing 727 aircraft owned by Zero Gravity Corp. is ready to take off with its well-known passenger, physicist Stephen Hawking. Zero Gravity Corp. is a commercial company licensed to provide the public with weightless flight experiences. Hawking will be making his first zero-gravity flight. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- At the Kennedy Space Center Shuttle Landing Facility, a modified Boeing 727 aircraft owned by Zero Gravity Corp. takes off with its well-known passenger, physicist Stephen Hawking. Zero Gravity Corp. is a commercial company licensed to provide the public with weightless flight experiences. Hawking will be making his first zero-gravity flight. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Jack Pfaller

KENNEDY SPACE CENTER, FLA. - The first group of passengers to fly on the ZERO-G aircraft are eager to get started. The Boeing 727-200 aircraft is used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. The passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - The first group of passengers to fly on the ZERO-G aircraft line up. The Boeing 727-200 aircraft is used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. The passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - The Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla., lands after taking a group of passengers for demonstration. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. This group of passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - The Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla., lands after taking a group of passengers for demonstration. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. This group of passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - A view inside the Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. A group of passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - The Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla., waits for its passengers. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. A group of passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

ZERO GRAVITY AIRCRAFT KC135 FLIGHTS AT LEWIS RESEARCH CENTER (Glenn Research Center)

Views of STS-51E PS Patrick Baudry during Zero-G Training Flights. 1. STS-51E - CREW TRAINING

Astronaut -Candidate (ASCAN) Guion S. Bluford and Aviation Safety Officer Charles F. Hayes got a unique perspective of their environment during a zero- gravity flight. They are aboard a KC-135 Aircraft, which flies a special pattern repeatedly to afford a series of 30-seconds-of-weightlessness sessions. Astronauts Bluford and Hayes are being assisted by C. P. Stanley of the Photography Branch of the Photographic Technology Division (PTD) at Johnson Space Center (JSC). Some medical studies and a Motion Sickness Experiment were conducted on this particular flight. Astronaut Bluford is one of 20 Scientist/ASCAN's who began training at JSC, 07/1978. 1. Dr. Jeffrey A. Hoffman - Zero-G 2. ASCAN Shannon Lucid - Zero-G 3. ASCAN Guion Bluford - Zero-G

KENNEDY SPACE CENTER, FLA. — Noted physicist Stephen Hawking greets the media after his arrival at the Kennedy Space Center Shuttle Landing Facility for his first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Noted physicist Stephen Hawking arrives at the Kennedy Space Center Shuttle Landing Facility for his first zero-gravity flight. The flight will be aboard a modified Boeing 727 aircraft owned by Zero Gravity Corp., a commercial company licensed to provide the public with weightless flight experiences. Hawking developed amyotrophic lateral sclerosis disease in the 1960s, a type of motor neuron disease which would cost him the loss of almost all neuromuscular control. At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Noted physicist Stephen Hawking (center) returns to the Kennedy Space Center Shuttle Landing Facility after a zero gravity flight. At his side is Nicola O'Brien, a nurse practitioner who is Hawking's aide. At far left on the truck's tail gate is Peter Diamandis, founder of the Zero Gravity Corp. that provided the flight aboard its modified Boeing 727. Hawking suffers from amyotrophic lateral sclerosis (also known as Lou Gehrig's disease). At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Well-wishers greet noted physicist Stephen Hawking (in the wheelchair) at the Kennedy Space Center Shuttle Landing Facility after a zero gravity flight. Next to him at left are Peter Diamandis, founder of the Zero Gravity Corp. that provided the flight aboard its modified Boeing 727, and Nicola O'Brien, a nurse practitioner who is Hawking's aide. Hawking suffers from amyotrophic lateral sclerosis (also known as Lou Gehrig's disease). At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. -- Well-wishers greet noted physicist Stephen Hawking (in the wheelchair) at the Kennedy Space Center Shuttle Landing Facility after a zero gravity flight. Next to him at left are Peter Diamandis, founder of the Zero Gravity Corp. that provided the flight aboard its modified Boeing 727, and Nicola O'Brien, a nurse practitioner who is Hawking's aide. Hawking suffers from amyotrophic lateral sclerosis (also known as Lou Gehrig's disease). At the celebration of his 65th birthday on January 8 this year, Hawking announced his plans for a zero-gravity flight to prepare for a sub-orbital space flight in 2009 on Virgin Galactic's space service. Photo credit: NASA/Kim Shiflett

KENNEDY SPACE CENTER, FLA. - The Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla., is airborne from Kennedy Space Center’s shuttle landing facility. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. The group of passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - The Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla., takes off from Kennedy Space Center’s shuttle landing facility. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. The group of passengers, called "Flyers," were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

KENNEDY SPACE CENTER, FLA. - Passengers known as “Flyers” disembark at Kennedy Space Center’s shuttle landing facility from a Boeing 727-200 aircraft used for weightless flights by Zero Gravity Corporation, known as ZERO-G, of Fort Lauderdale, Fla. NASA and ZERO-G demonstrated Nov. 5 the expanded access to and use of the space shuttle's runway and landing facility at Kennedy Space Center for non-NASA activities. The “Flyers” were predominantly teachers who performed simple microgravity experiments they can share with their students back in the classroom.

AS17-162-24053 (7-19 Dec. 1972) --- Scientist-astronaut Harrison H. "Jack" Schmitt, lunar module pilot, took this photograph of his two fellow crew men under zero-gravity conditions aboard the Apollo 17 spacecraft during the final lunar landing mission in NASA's Apollo program. That is astronaut Eugene A. Cernan, commander, who is seemingly "right side up." Astronaut Ronald E. Evans, command module pilot, appears to be "upside down." While astronauts Cernan and Schmitt descended in the Lunar Module (LM) "Challenger" to explore the Taurus-Littrow region of the moon, astronaut Evans remained with the Command and Service Modules (CSM) "America" in lunar orbit.

S84-37536 (18 July 1984) --- Astronaut Robert L. Crippen, left, 41-G crew commander watches as one of his fellow crewmembers gets an introduction to weightlessness aboard a KC-135, "zero-gravity" aircraft. Paul D. Scully-Power is the crew member literally floating here in the brief period of micro-gravity. Scully-Power, an oceanographer with the U.S. Navy, and Marc Garneau (partially visible in chair behind the floating Scully-Power)are payload specialists for 41-G. Garneau represents the National Research Council (Canada).

S84-37522 (18 July 1984) --- Astronaut Jon A. McBride, center, floats briefly aboard a NASA KC-135 aircraft during a flight designed as part of the training program for 41-G's seven crewmembers. McBride is pilot for that October 1984 flight. Marc Garneau, one of two payload specialists for the mission, is seated at right. Garneau represents the National Research Council of Canada.

iss071e046284 (May 1, 2024) -- One of the International Space Station's free-flying robots, Astrobee, was pictured by NASA astronaut and Expedition 71 Flight Engineer Tracy C. Dyson during a Zero Robotics tech demonstration. Zero Robotics allows students on Earth to write software to control the robots and observe their performance inside the orbiting laboratory.

iss071e046270 (May 1, 2024) -- NASA astronaut and Expedition 71 Flight Engineer Tracy C. Dyson performs a Zero Robotics tech demonstration with Astrobee. Zero Robotics allows students on Earth to write software to control one of three free-flying Astrobee robots aboard the International Space Station. As part of an ongoing educational activity, students can then observe the performance of the robot without directly interacting with it.

S85-42473 (16 Oct. 1985) --- Sharon Christa McAuliffe, a teacher-citizen observer on STS-51L, smiles before participating in some zero-G rehearsals for her upcoming flight. She is seated near the controls of the KC-135 aircraft, flying for the Johnson Space Center from Ellington Air Field. Referred to as the ?zero-gravity? aircraft, the KC-135 provides brief moments of weightlessness for shuttle crew members in training. Photo credit: NASA

ISS009-E-10551 (4 June 2004) --- Astronaut Edward M. (Mike) Fincke, Expedition 9 NASA ISS science officer and flight engineer, moves the Zero-G Storage Rack (ZSR) in the Destiny laboratory of the International Space Station (ISS) in order to retrieve the spare Remote Power Controller Module (RPCM), scheduled to replace the failed RPCM on the S0 (S-Zero) Truss. Fincke is positioned above the ZSR, which has been pulled from the Express Rack.

NIKI WERKHEISER - 3D PRINTING ZERO-G PROJECT MANAGER, DISCUSSES 3D PRINTING TECHNOLOGY WITH DR. ELLEN OCHOA.1401414 THE ISS NOW HAS A 3D PRINTER, WHICH THE TECHNOLOGY WAS TESTED AT THE MARSHALL SPACE FLIGHT CENTER

ISS038-E-031382 (14 Jan. 2014) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, works at the Zero-Gravity Stowage Rack (ZSR) in the Kibo laboratory of the International Space Station.

S91-38355 (28 May 1991) --- Seen floating about the vacant spaces of the Johnson Space Center's KC-135 "zero-gravity" aircraft are the six crewmembers for the STS 44 mission. Left to right are Terence T. Henricks, James S. Voss, F. Story Musgrave (partially obscured), Frederick D. Gregory, Thomas J. Hennen and Mario Runco Jr. Gregory is mission commander. Hennen is payload specialist for this flight, dedicated to the Department of Defense. The flight served as a refresher and a preview of the experience of weightlessness, as the special aircraft flew a series of parabolas which provided short sessions of zero-gravity.

S91-38355 (28 May 1991) --- Seen floating about the vacant spaces of the Johnson Space Center's KC-135 "zero-gravity" aircraft are the six crewmembers for the STS 44 mission. Left to right are Terence T. Henricks, James S. Voss, F. Story Musgrave (partially obscured), Frederick D. Gregory, Thomas J. Hennen and Mario Runco Jr. Gregory is mission commander. Hennen is payload specialist for this flight, dedicated to the Department of Defense. The flight served as a refresher and a preview of the experience of weightlessness, as the special aircraft flew a series of parabolas which provided short sessions of zero-gravity.

ISS008-E-05865 (12 November 2003) --- Cosmonaut Alexander Y. Kaleri, Expedition 8 flight engineer, moves a Zero-G Storage Rack (ZSR) in the Destiny laboratory on the International Space Station (ISS). Kaleri, who represents Rosaviakosmos, commanded the Soyuz flight that took the crew to the station last month.

ISS008-E-05854 (12 November 2003) --- Cosmonaut Alexander Y. Kaleri, Expedition 8 flight engineer, moves a Zero-G Storage Rack (ZSR) in the Destiny laboratory on the International Space Station (ISS). Kaleri, who represents Rosaviakosmos, commanded the Soyuz flight that took the crew to the station last month.

ISS008-E-05856 (12 November 2003) --- Cosmonaut Alexander Y. Kaleri, Expedition 8 flight engineer, moves a Zero-G Storage Rack (ZSR) in the Destiny laboratory on the International Space Station (ISS). Kaleri, who represents Rosaviakosmos, commanded the Soyuz flight that took the crew to the station last month.

Dr. E. Stuhlinger, Dr. W. von Braun, and Dr. J. Piccard, along with others, take a swim in the Neutral Buoyancy Simulator (NBS) at the Marshall Space Flight Center. The NBS was instrumental in providing a zero-gravity environment where astronauts could practice tasks assigned for up coming space flights.

STS005-04-124 (14 Nov. 1982) --- Three members of the four-man STS-5 crew demonstrate the zero-gravity environment aboard the Earth-orbiting space shuttle Columbia. Astronaut Vance D. Brand, mission commander, holds a fairly typical Earth-bound pose, but crewmates, astronauts Robert F. Overmyer (center), pilot, and Dr. William B. Lenoir, mission specialist, perform body movements that could only be accomplished in zero-gravity. Dr. Joseph P. Allen IV, the flight’s other mission specialist, exposed this frame with a 35mm handheld camera. The four astronauts were in the middeck area of their reusable spacecraft when this photograph was made. Photo credit: NASA

Researchers at NASA's Kennedy Space Center in Florida are developing a Zero Launch Mass 3-D printer at the center's Swamp Works. The printer can be used for construction projects on the Moon and Mars. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers. This will prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The Kennedy team is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

A Zero Launch Mass 3-D printer is being developed by researchers in Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers. This will prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The Kennedy team is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

A Zero Launch Mass 3-D printer is being tested at the Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers. This will prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The Kennedy team is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

Researchers demonstrate a Zero Launch Mass 3-D printer in Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers. This will prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The Kennedy team is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

S84-40538 (24 Aug 1984) --- Two 41-G payload specialists and a backup for one of them appear to be at home in zero gravity in this scene photographed aboard a KC-135 "Zero gravity" aircraft flying one of its weightlessness opportunity parabolas. Paul D. Scully-Power, a civilian oceanographer with the U.S. Navey, is flanked by Marc Garneau (left) and Robert Thirsk, both representing the National Research Council of Canada. Thirsk is back up payload specialist for Garneau.

Paul Scully-Power, 41-G payload specialist, links arms with two others as they experience weightlessness in the KC-135 training aircraft. The trio appears to be flying toward the front of the aircraft while others take photos.

View of astronaut candidates and payload specialists during a training flight on the KC-135. The trainees are experiencing weightlessness in the hold of the aircraft.

ISS030-E-156310 (23 Jan. 2012) --- European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, works with the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) experiment in the Kibo laboratory of the International Space Station.

ISS034-E-028342 (11 Jan. 2013) --- NASA astronauts Kevin Ford (left), Expedition 34 commander; and Tom Marshburn, flight engineer, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

ISS040-E-018417 (24 June 2014) --- Russian cosmonaut Oleg Artemyev (left) and NASA astronaut Reid Wiseman, both Expedition 40 flight engineers, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

ISS040-E-018486 (24 June 2014) --- Russian cosmonaut Oleg Artemyev (left) and NASA astronaut Reid Wiseman, both Expedition 40 flight engineers, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

S81-30420 (12-14 April 1981) --- Astronaut Robert L. Crippen, pilot for STS-1 takes advantage of zero-gravity to do some rare acrobatics on the middeck of the space shuttle Columbia in Earth orbit. This 35mm frame was exposed by astronaut John W. Young, flight crew commander. Photo credit: NASA

An astronaut wearing a pressurized space suit performed a work task while suspended in a “zero-gravity” simulator known as the Neutral Buoyancy Simulator (NBS) at Marshall Space Flight Center. This particular task was one of many performed by astronauts while checking out the mockup for the Apollo Telescope Mount.

ISS040-E-018390 (24 June 2014) --- Russian cosmonaut Oleg Artemyev (left) and NASA astronaut Reid Wiseman, both Expedition 40 flight engineers, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

ISS040-E-018572 (24 June 2014) --- Russian cosmonaut Oleg Artemyev (left) and NASA astronaut Reid Wiseman, both Expedition 40 flight engineers, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

ISS040-E-018466 (24 June 2014) --- Russian cosmonaut Oleg Artemyev (left) and NASA astronaut Reid Wiseman, both Expedition 40 flight engineers, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

iss061e145487 (Jan. 28, 2020) --- NASA astronaut and Expedition 61 Flight Engineer Jessica Koch works on the Cold Atom Lab (CAL) swapping and cleaning hardware inside the quantum research device. The CAL enables research into the quantum effects of gases chilled to nearly absolute zero, which is colder than the average temperature of the universe.

ISS017-E-018977 (9 Oct. 2008) --- NASA astronaut Greg Chamitoff, Expedition 17 flight engineer, works in the Kibo laboratory to move a zero-g stowage rack (ZSR) during a relocation task. The ZSR was previously in the Destiny laboratory of the International Space Station.

ISS040-E-018383 (24 June 2014) --- Russian cosmonaut Oleg Artemyev (left) and NASA astronaut Reid Wiseman, both Expedition 40 flight engineers, conduct a session of the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) program in the Kibo laboratory of the International Space Station.

ISS038-E-031384 (14 Jan. 2014) --- Japan Aerospace Exploration Agency astronaut Koichi Wakata, Expedition 38 flight engineer, holds a brass ring at the Zero-Gravity Stowage Rack (ZSR) in the Kibo laboratory of the International Space Station.

Astronaut Norman E. Thagard, mission specialist for the "silver" team, rests on the middeck while the "gold" team is on duty in the science module. Don L. Lind, left, "gold" team member, meanwhile participates in autogenic feedback training (AFT), designed to help flight crewmembers overcome the effects of zero-gravity adaptation.

ISS030-E-156313 (23 Jan. 2012) --- European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, works with the Synchronized Position Hold, Engage, Reorient, Experimental Satellites Zero Robotics (SPHERES ZR) experiment in the Kibo laboratory of the International Space Station.

This chart describes the Skylab student experiment In-Vitro Immunology, proposed by Todd A. Meister of Jackson Heights, New York. He suggested an in-vitro observation of the effects of zero-gravity on a presipitin-type antigen-antibody reaction, as compared with the same reaction carried out in an Earth-based laboratory. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

This chart describes the Skylab student experiment Libration Clouds, proposed by Alison Hopfield of Princeton, New Jersey. This experiment utilized Skylab's astronomical telescopes to observe the two zero-force regions (Lagrangian points) within the Earth-Moon System in which small space particles were expected to accumulate. In March 1972, NASA and the National Science Teachers Association selected 25 experiment proposals for flight on Skylab. Science advisors from the Marshall Space Flight Center aided and assisted the students in developing the proposals for flight on Skylab.

This August 1971 interior photograph of Skylab's Multiple Docking Adapter (MDA) flight article, undergoing outfitting at the Martin-Marietta Corporation's Space Center facility in Denver, Colorado, shows the forward cone area and docking tunnel (center) that attached to the Apollo Command Module. Designed and manufactured by the Marshall Space Flight Center, the MDA housed the control units for the Apollo Telescope Mount, Earth Resources Experiment Package, and Zero-Gravity Materials Processing Facility and provided a docking port for the Apollo Command Module.

This interior photograph of Skylab's multiple docking adapter (MDA) flight article, then undergoing outfitting at the Martin Marietta Corporation's Space Center facility in Denver, Colorado, shows the forward cone area and docking turnel (center) that attached to the Apollo Command Module. Designed and manufactured by the Marshall Space Flight Center, the MDA housed the control units for the Apollo Telescope Mount (ATM), Earth Resources Experiment Package (EREP), and Zero-Gravity Materials Processing Facility and provided a docking port for the Apollo Command Module.

S87-44950 --- Group 12, 1987 Astronaut Class, candidates (ASCANs) N. Jan Davis (left) and Mae C. Jemison freefloat during the seconds of microgravity created aboard the KC-135 NASA 930 aircraft's parabolic flight. Davis and Jemison, two of the recently-named ASCANs, were taking a familiarization flight aboard the KC-135 "zero gravity" aircraft. Photo credit: NASA

The Reduced-Gravity Program provides the unique weightless or zero-g environment of space flight for testing and training of human and hardware reactions. The reduced-gravity environment is obtained with a specially modified KC-135A turbojet transport which flies parabolic arcs to produce weightless periods of 20 to 25 seconds. KC-135A cargo bay test area is approximately 60 feet long, 10 feet wide, and 7 feet high. The image shows KC-135A in flight.

Workmen at the Martin Marietta Corporation's Space Center in Denver, Colorado, position Skylab's Multiple Docking Adapter (MDA) flight article in the horizontal transportation fixture. Designed and manufactured by the Marshall Space Flight Center and outfitted by Martin Marietta, the MDA housed the control units for the Apollo Telescope Mount (ATM), Earth Resources Experiment Package (EREP), and Zero-Gravity Materials Processing Facility and provided a docking port for the Apollo Command Module.

Dr. von Braun inside the KC-135 in flight. The KC-135 provide NASA's Reduced-Gravity Program the unique weightlessness or zero-g environment of space flight for testing and training of human and hardware reactions. The recent version, KC-135A, is a specially modified turbojet transport which flies parabolic arcs to produce weightlessness periods of 20 to 25 seconds and its cargo bay test area is approximately 60 feet long, 10 feet wide, and 7 feet high.

At Marshall Space Flight Center, Skylab's Multiple Docking Adapter (MDA) flight article undergoes center-of-gravity testing. Developed and fabricated by MSFC, the MDA housed the control units for the Apollo Telescope Mount (ATM), Earth Resources Experiment Package (EREP), and the Zero-Gravity Material Processing Facility and provided a docking port for the Apollo Command Module.

Nathan Gelino, a NASA research engineer at Kennedy Space Center in Florida, is working on a Zero Launch Mass 3-D printer in the center's Swamp Works that can be used for construction projects on the Moon and Mars, and even for troops in remote locations here on Earth. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. Gelino and his team are working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

Research engineers at NASA's Kennedy Space Center in Florida are working on a Zero Launch Mass 3-D printer at the center's Swamp Works. The printer can be used for construction projects on the Moon and Mars, and even for troops in remote locations on Earth. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The group is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

Nathan Gelino, a NASA research engineer at Kennedy Space Center in Florida displays a 3-D printed cylinder used for compression testing. Engineers at the center’s Swamp Works measured how much force it takes to break the structure before moving on to 3-D printing with a simulated lunar regolith, or dirt, and polymers. Next, Gelino and his group are working on a Zero Launch Mass 3-D printer that can be used for construction projects on the Moon and Mars, even for troops in remote locations here on Earth. Zero launch mass refers to the fact that the printer uses these pellets to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. Gelino and his team are working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

Pellets made from simulated lunar regolith, or dirt, and polymers are being used to test a Zero Launch Mass 3-D printer in the Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars, and even for troops in remote locations on Earth. Zero launch mass refers to the fact that the printer uses these pellets to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The group is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

Research engineers at NASA's Kennedy Space Center in Florida are working on a Zero Launch Mass 3-D printer at the center's Swamp Works. The printer can be used for construction projects on the Moon and Mars, and even for troops in remote locations on Earth. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The group is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

A Zero Launch Mass 3-D printer is being tested at the Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars, and even for troops in remote locations on Earth. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The group is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

A Zero Launch Mass 3-D printer is being tested at the Swamp Works at NASA's Kennedy Space Center in Florida. The printer can be used for construction projects on the Moon and Mars, and even for troops in remote locations on Earth. Zero launch mass refers to the fact that the printer uses pellets made from simulated lunar regolith, or dirt, and polymers to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. The group is working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

Nathan Gelino, a NASA research engineer at Kennedy Space Center in Florida displays a 3-D printed cylinder used for compression testing. Engineers at the center’s Swamp Works measured how much force it takes to break the structure before moving on to 3-D printing with a simulated lunar regolith, or dirt, and polymers. Next, Gelino and his group are working on a Zero Launch Mass 3-D printer that can be used for construction projects on the Moon and Mars, even for troops in remote locations here on Earth. Zero launch mass refers to the fact that the printer uses these pellets to prove that space explorers can use resources at their destination instead of taking everything with them, saving them launch mass and money. Gelino and his team are working with Marshall Space Flight Center in Huntsville, Alabama, and the U.S. Army Corps of Engineers to develop a system that can 3-D print barracks in remote locations on Earth, using the resources they have where they are.

S65-30430 (3 June 1965) --- Astronaut Edward H. White II, pilot on the Gemini-Titan 4 spaceflight, is shown during his egress from the spacecraft. His face is covered by a shaded visor to protect him from the unfiltered rays of the sun. White became the first American astronaut to walk in space. He remained outside the spacecraft for 21 minutes during the third revolution of the Gemini-4 mission. He wears a specially designed spacesuit for the extravehicular activity (EVA). In his right hand, he carries a Hand-Held Self-Maneuvering Unit (HHSMU) with which he controlled his movements while in space. He was attached to the spacecraft by a 25-feet umbilical line and a 23-feet tether line, both wrapped together with gold tape to form one cord. He wears an emergency oxygen supply chest pack. Astronaut James A. McDivitt is command pilot for the Gemini-4 mission. Photo credit: NASA EDITOR'S NOTE: Astronaut Edward H. White II died in the Apollo/Saturn 204 fire at Cape Kennedy on Jan. 27, 1967.

S65-34635 (3 June 1965) --- Astronaut Edward H. White II, pilot on the Gemini-Titan 4 spaceflight, is shown during his egress from the spacecraft. His face is covered by a shaded visor to protect him from the unfiltered rays of the sun. White became the first American astronaut to walk in space. He remained outside the spacecraft for 21 minutes during the third revolution of the Gemini-4 mission. He wears a specially designed spacesuit for the extravehicular activity (EVA). In his right hand, he carries a Hand-Held Self-Maneuvering Unit (HHSMU) with which he controlled his movements while in space. He was attached to the spacecraft by a 25-feet umbilical line and a 23-feet tether line, both wrapped together with gold tape to form one cord. He wears an emergency oxygen supply chest pack. Astronaut James A. McDivitt is command pilot for the Gemini-4 mission. EDITOR'S NOTE: Astronaut Edward H. White II died in the Apollo/Saturn 204 fire at Cape Kennedy on Jan. 27, 1967.

Zero-g tests of involving Astronaut candidate Daniel C. Brandenstein. Brandenstein is shown flying in midair on the KC-135.

S84-37532 (18 July 1984) --? Robert B. Thirsk, backup payload specialist for 41-G appears to be shaking hands with an unoccupied extravehicular mobility unit (EMU) during a familiarization flight aboard NASA?s KC-135 aircraft. Thirsk, representing Canada?s National Research Council (NRC), serves as backup to Marc Garneau on the seven-member crew for Challenger?s October 1984 flight. This aircraft is used extensively for training and exposing Shuttle crewmembers to weightlessness as well as for evaluation of equipment and experiments scheduled for future flights.

S86-25180 (October 1985) --- Sharon Christa McAuliffe, STS-51L citizen observer/payload specialist, representing the Teacher-in-Space Project, floats forward and upward during a few moments of weightlessness aboard a KC-135 aircraft. The flight is part of her training for the scheduled five-day flight aboard the Challenger in January of next year. Barbara R. Morgan, backup payload specialist for STS-51L, is partially visible in the background. The photo was taken by Keith Meyers of the New York Times. Photo credit: NASA

S65-30427 (3 June 1965) --- Astronaut Edward H. White II, pilot for the Gemini-Titan 4 (GT-4) spaceflight, floats in the zero-gravity of space during the third revolution of the GT-4 spacecraft. White wears a specially designed spacesuit. His face is shaded by a gold-plated visor to protect him from unfiltered rays of the sun. In his right hand he carries a Hand-Held Self-Maneuvering Unit (HHSMU) that gives him control over his movements in space. White also wears an emergency oxygen chest pack; and he carries a camera mounted on the HHSMU for taking pictures of the sky, Earth and the GT-4 spacecraft. He is secured to the spacecraft by a 25-feet umbilical line and a 23-feet tether line. Both lines are wrapped together in gold tape to form one cord. Astronaut James A. McDivitt, command pilot, remained inside the spacecraft during the extravehicular activity (EVA). Photo credit: NASA EDITOR'S NOTE: Astronaut Edward H. White II died in the Apollo/Saturn 204 fire at Cape Kennedy on Jan. 27, 1967.

S72-50270 (September 1972) --- Astronaut Eugene A. Cernan, commander of the Apollo 17 lunar landing mission, participates in lunar surface extravehicular activity simulation training under one-sixth gravity conditions aboard a U. S. Air Force KC-135 aircraft. Here, Cernan simulates removing an experiment package from the aft end of a Lunar Roving Vehicle.

Skylab's Body Mass Measurement chair, the facility of the Body Mass Measurement experiment (M172), is shown here in this 1970 photograph. The M172 experiment determined the body mass of each crew member and observed changes in body masses during flight. Knowledge of exact body mass variations throughout the flight in significantly aided in the correlation of other medical data obtained during the flight. Mass measurements under zero-gravity conditions were achieved by the application of Newton's second law (force equals mass times acceleration). The Marshall Space Flight Center had program management responsibility for the development of Skylab hardware and experiments.

The X-56B remotely piloted aircraft lands following the first of a new flight series. The flight was April 19 at NASA's Armstrong Flight Research Center in Edwards, California, with partner Northrop Grumman.

The X-56B remotely piloted aircraft ground crew prepares the aircraft to begin a new flight series. The flight was April 19 at NASA's Armstrong Flight Research Center in Edwards, California, with partner Northrop Grumman.

The X-56B remotely piloted aircraft lands following the first of a new flight series. The flight was April 19 at NASA's Armstrong Flight Research Center in Edwards, California, with partner Northrop Grumman.