After a brief delay to fix what NASA called a "minor leak" in crew member Steve Bowen's spacesuit, Discovery astronauts March 2 began their second spacewalk of the mission.
The spacewalk began shortly before 11 a.m. EST. According to a tweet from NASA, the leak in Bowen's space suit was caused by a problem with an O-ring inserted in a lithium hydroxide canister. A replacement O-ring was put in place, and the spacewalk began. Earlier in the morning, the shuttle crew was awakened by a call from Mission Control Houston that featured the song, "The Speed of Sound" by Coldplay, which was played for Pilot Eric Boe.
Mission Specialist Nicole Stott is choreographing the spacewalk as the intravehicular officer while Mission Specialist Mike Barratt and station Commander Scott Kelly operate the Canadarm2 from the robotic workstation in the station's cupola. The spacewalkers are scheduled to perform several tasks during their excursion, including venting ammonia from the failed pump module they moved to a storage location the spacewalk Feb. 28.
They also are removing a lightweight adapter plate previously used to attach experiments to the exterior of the Columbus laboratory and remove insulation from the Tranquility node and the newly installed Express Logistics Carrier 4. The spacewalkers also will install a light on one of the crew equipment and translation aid carts; install a light and a pan and tilt assembly on Dextre, the space station's Special Purpose Dexterous Manipulator; and troubleshoot a loose radiator grapple fixture stowage beam, which would be used if a radiator ever needed to be replaced.
The spacewalk is expected to last 6 hours and 30 minutes. Meanwhile, crew members inside the complex will continue transferring more cargo from Discovery and loading trash into the Japanese Kounotouri2 H-II Transfer Vehicle for eventual disposal. In addition, the International Space Station has a new room, filled with equipment, supplies and a new device that could be a precursor of spacewalking robots.
The PMM (Permanent Multipurpose Module), Leonardo, was installed on the Earth-facing port of the station's Unity node Tuesday. The PMM adds 2,472 cubic feet of pressurized storage space to the station, and it brings to the station, in addition to a humanoid robot called Robonaut 2, a payload of about 28,000 pounds. It includes an express rack capable of housing a variety of scientific experiments, five resupply stowage racks, six resupply stowage platforms and two integrated stowage platforms.
Bowen replaced Tim Kopra as mission specialist 2 following a bicycle injury Jan. 15 that prohibited Kopra from supporting the launch window. Bowen last flew on Atlantis in May 2010 as part of the STS-132 crew. Flying on the STS-133 mission will make Bowen the first astronaut ever to fly on consecutive missions.
The shuttle has flown 38 flights, completed 5,247 orbits and spent 322 days in orbit. The shuttle is the orbiter fleet leader, having flown more flights than any other orbiter in the fleet, including four in 1985 alone. Discovery also flew all three "return to flight" missions after the Challenger and Columbia disasters.
Discovery was also the shuttle that launched the Hubble Space Telescope and the Ulysses probe designed to study the Sun. In addition, Discovery carried Project Mercury astronaut John Glenn, who was 77 at the time, back into space during STS-95 in October 1998, making him the oldest person to venture into space.