CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, STS-133 NASA Test Director Stephen Payne sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room-4 in the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers took their posts at about 2:30 p.m. EST for space shuttle Discovery's STS-133 mission to the International Space Station. The countdown clock began ticking backward from the T-43 hour mark at 3 p.m. Scheduled to lift off Feb. 24 at 4:50 p.m. EST, Discovery and its six-member crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, STS-133 launch team members rehearse procedures for the liftoff of space shuttle Discovery's final mission in Firing Room 4. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Seen on display overhead are the five orbiter tribute wall hangings. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, STS-133 Assistant Launch Director Pete Nickolenko sits at his console in Firing Room 4 along with other launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA Test Director Charlie Blackwell-Thompson sits at her console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- At NASA's Kennedy Space Center in Florida, STS-133 launch team members rehearse procedures for the liftoff of space shuttle Discovery's final mission in Firing Room 4. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA Orbiter Project Engineer Todd Campbell sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, United Space Alliance Safety Engineer Dwayne Thompson, left, and NASA Safety Engineer Dallas McCarter rehearse procedures for the liftoff of space shuttle Discovery's final mission with other STS-133 launch team members in Firing Room 4. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, United Space Alliance Guidance and Navigation Engineer Jennifer Guida sits at her console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, Assistant Launch Orbiter Test Conductor Mark Taffet sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA Test Director Robert Holl sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, Launch Orbiter Test Conductor John Kracsun sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of space shuttle Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, Bart Pannullo, the vehicle processing engineer for space shuttle Discovery, sits at his console in Firing Room 4 along with other STS-133 launch team members to rehearse procedures for the liftoff of Discovery's final mission. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

STS133-S-063 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, the launch team monitors the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-064 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, STS-133 Assistant Shuttle Launch Director and Lead NASA Test Director Charlie Blackwell-Thompson monitors the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

NASA management watch the launch of space shuttle Discovery (STS-133) from the firing room at Kennedy Space Center, Thursday, Feb. 24, 2011, in Cape Canaveral, Fla. Discovery, on its 39th and final flight, is carrying the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden and other NASA management watch the launch of space shuttle Discovery (STS-133) from the firing room at Kennedy Space Center, Thursday, Feb. 24, 2011, in Cape Canaveral, Fla. Discovery, on its 39th and final flight, is carrying the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden and other NASA management watch the launch of space shuttle Discovery (STS-133) from the firing room at Kennedy Space Center, Thursday, Feb. 24, 2011, in Cape Canaveral, Fla. Discovery, on its 39th and final flight, is carrying the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden and other NASA management watch the launch of space shuttle Discovery (STS-133) from the firing room at Kennedy Space Center, Thursday, Feb. 24, 2011, in Cape Canaveral, Fla. Discovery, on its 39th and final flight, is carrying the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

NASA Administrator Charles Bolden and other NASA management watch the launch of space shuttle Discovery (STS-133) from the firing room at Kennedy Space Center, Thursday, Feb. 24, 2011, in Cape Canaveral, Fla. Discovery, on its 39th and final flight, is carrying the Italian-built Permanent Multipurpose Module (PMM), Express Logistics Carrier 4 (ELC4) and Robonaut 2, the first humanoid robot in space to the International Space Station. Photo Credit: (NASA/Bill Ingalls)

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach monitors the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, the Mission Management Team monitors the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA Administrator Charlie Bolden congratulates the launch team after the successful liftoff of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Associate Administrator for Space Operations Bill Gerstenmaier and NASA Administrator Charlie Bolden monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach watches space shuttle Discovery blaze a trail of smoke and steam as it heads toward orbit on the STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, the launch team monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In the Launch Control Center at NASA's Kennedy Space Center in Florida, Mechanisms/Orbiter Handling Engineer Rob Lantz, left, and United Space Alliance Remote Manipulator System Engineer Paul Hofmeister, rehearse procedures for the liftoff of space shuttle Discovery's final mission with other STS-133 launch team members in Firing Room 4. The team at Kennedy also participated in launch simulations with personnel at NASA's Johnson Space Center in Houston. Discovery's next launch opportunity to the International Space Station on the STS-133 mission is planned for no earlier than Feb. 24. For more information on STS-133, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach and his team monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

STS133-S-067 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA's Discovery Flow Director Stephanie Stilson, left, STS-133 Assistant Shuttle Launch Director and lead NASA Test Director Charlie Blackwell-Thompson and Shuttle Launch Director Mike Leinbach watch space shuttle Discovery head toward Earth orbit on the STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach gives the "go" to launch space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Stennis Center Director Patrick Scheuermann, left, Kennedy's Center Director Bob Cabana, Johnson Space Center Director Mike Coats and Marshall Center Director Robert Lightfoot (extreme right), monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- In Firing Room-4 in the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers took their posts at about 2:30 p.m. EST for space shuttle Discovery's STS-133 mission to the International Space Station. The countdown clock began ticking backward from the T-43 hour mark at 3 p.m. Scheduled to lift off Feb. 24 at 4:50 p.m. EST, Discovery and its six-member crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- In Firing Room-4 in the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers took their posts at about 2:30 p.m. EST for space shuttle Discovery's STS-133 mission to the International Space Station. The countdown clock began ticking backward from the T-43 hour mark at 3 p.m. Scheduled to lift off Feb. 24 at 4:50 p.m. EST, Discovery and its six-member crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Frank Michaux

CAPE CANAVERAL, Fla. -- In Firing Room-4 in the Launch Control Center at NASA's Kennedy Space Center in Florida, launch controllers took their posts at about 2:30 p.m. EST for space shuttle Discovery's STS-133 mission to the International Space Station. The countdown clock began ticking backward from the T-43 hour mark at 3 p.m. Scheduled to lift off Feb. 24 at 4:50 p.m. EST, Discovery and its six-member crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Frank Michaux

STS133-S-061 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA Administrator Charlie Bolden (foreground) and Associate Administrator for Space Operations Bill Gerstenmaier monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-068 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA Administrator Charlie Bolden congratulates the launch team after the successful liftoff of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-066 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach watches space shuttle Discovery head toward Earth orbit on the STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-065 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach gives the "go" to launch space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-059 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach monitors the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-062 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Stennis Center Director Patrick Scheuermann, left, Kennedy's Center Director Bob Cabana, Johnson Space Center Director Mike Coats and Marshall Center Director Robert Lightfoot (extreme right), monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

STS133-S-060 (24 Feb. 2011) --- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, Shuttle Launch Director Mike Leinbach (standing at right) and his team monitor the countdown to launch of space shuttle Discovery on its STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. Photo credit: NASA or National Aeronautics and Space Administration

CAPE CANAVERAL, Fla. -- In Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida, NASA's Discovery Flow Director Stephanie Stilson, left, STS-133 Assistant Shuttle Launch Director and lead NASA Test Director Charlie Blackwell-Thompson and Shuttle Launch Director Mike Leinbach watch space shuttle Discovery blaze a trail of smoke and steam as it heads toward orbit on the STS-133 mission to the International Space Station. Discovery and its six-member crew are on a mission to deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the orbiting outpost. Discovery is making its 39th mission and is scheduled to be retired following STS-133. This is the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Kim Shiflett

CAPE CANAVERAL, Fla. -- This orbiter tribute of space shuttle Discovery, or OV-103, hangs in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. In 2011, the tribute was updated to reflect the crew member change on Discovery's final mission -- STS-133. Steve Bowen replaced Tim Kopra as a mission specialist on STS-133, after Kopra was injured in a bicycle accident that prevented him from flying into space. Discovery’s accomplishments include the first female shuttle pilot, Eileen Collins, on STS-63, John Glenn’s legendary return to space on STS-95, and the celebration of the 100th shuttle mission with STS-92. In addition, Discovery supported a number of Department of Defense programs, satellite deploy and repair missions and 13 International Space Station construction and operation flights. The tribute features Discovery demonstrating the rendezvous pitch maneuver on approach to the International Space Station during STS-114. Having accumulated the most space shuttle flights, Discovery’s 39 mission patches are shown circling the spacecraft. The background image was taken from the Hubble Space Telescope, which launched aboard Discovery on STS-31 and serviced by Discovery on STS-82 and STS-103. The American Flag and Bald Eagle represent Discovery’s two Return-to-Flight missions -- STS-26 and STS-114 -- and symbolize Discovery’s role in returning American astronauts to space. Five orbiter tributes are on display in the firing room, representing Atlantis, Challenger, Columbia, Endeavour and Discovery. Graphic design credit: NASA/Amy Lombardo. NASA publication number: SP-2010-08-164-KSC

CAPE CANAVERAL, Fla. -- This is a version of space shuttle Discovery's orbiter tribute, or OV-103, which hangs in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. In 2011, the tribute was updated to reflect the crew member change on Discovery's final mission -- STS-133. Steve Bowen replaced Tim Kopra as a mission specialist on STS-133, after Kopra was injured in a bicycle accident that prevented him from flying into space. Discovery’s accomplishments include the first female shuttle pilot, Eileen Collins, on STS-63, John Glenn’s legendary return to space on STS-95, and the celebration of the 100th shuttle mission with STS-92. In addition, Discovery supported a number of Department of Defense programs, satellite deploy and repair missions and 13 International Space Station construction and operation flights. The tribute features Discovery demonstrating the rendezvous pitch maneuver on approach to the International Space Station during STS-114. Having accumulated the most space shuttle flights, Discovery’s 39 mission patches are shown circling the spacecraft. The background image was taken from the Hubble Space Telescope, which launched aboard Discovery on STS-31 and serviced by Discovery on STS-82 and STS-103. The American Flag and Bald Eagle represent Discovery’s two Return-to-Flight missions -- STS-26 and STS-114 -- and symbolize Discovery’s role in returning American astronauts to space. Five orbiter tributes are on display in the firing room, representing Atlantis, Challenger, Columbia, Endeavour and Discovery. Graphic design credit: NASA/Amy Lombardo. NASA publication number: SP-2010-08-164-KSC

CAPE CANAVERAL, Fla. -- This is a printable version of space shuttle Discovery's orbiter tribute, or OV-103, which hangs in Firing Room 4 of the Launch Control Center at NASA's Kennedy Space Center in Florida. In 2011, the tribute was updated to reflect the crew member change on Discovery's final mission -- STS-133. Steve Bowen replaced Tim Kopra as a mission specialist on STS-133, after Kopra was injured in a bicycle accident that prevented him from flying into space. Discovery’s accomplishments include the first female shuttle pilot, Eileen Collins, on STS-63, John Glenn’s legendary return to space on STS-95, and the celebration of the 100th shuttle mission with STS-92. In addition, Discovery supported a number of Department of Defense programs, satellite deploy and repair missions and 13 International Space Station construction and operation flights. The tribute features Discovery demonstrating the rendezvous pitch maneuver on approach to the International Space Station during STS-114. Having accumulated the most space shuttle flights, Discovery’s 39 mission patches are shown circling the spacecraft. The background image was taken from the Hubble Space Telescope, which launched aboard Discovery on STS-31 and serviced by Discovery on STS-82 and STS-103. The American Flag and Bald Eagle represent Discovery’s two Return-to-Flight missions -- STS-26 and STS-114 -- and symbolize Discovery’s role in returning American astronauts to space. Five orbiter tributes are on display in the firing room, representing Atlantis, Challenger, Columbia, Endeavour and Discovery. Graphic design credit: NASA/Amy Lombardo. NASA publication number: SP-2010-08-164-KSC