Space Shuttle Endeavour Crew Performs First Spacewalk

The first of four spacewalks on Endeavour's final mission to the International Space Station is under way.

Endeavour crew members Drew Feustel and Greg Chamitoff are well under way in the first of four planned spacewalks on the shuttle's last mission into space. NASA reported they have completed the installation of the ammonia jumper cable that will connect the cooling loops of the station's port-3 and 4 segments.

The space agency reported this task was necessary for activities scheduled for the second spacewalk in which Feustel and Mike Fincke will top off the ammonia in the station's port-6 photovoltaic thermal control system cooling loop, which has a slow ammonia leak. They started by installing the cable, then they vented nitrogen from the loops between the port-1 and port-5 segments and from the jumper that connects the ammonia reservoir that will be used for the refill on the second spacewalk. Next, they will move on to the Destiny laboratory for their final major task for May 20, where they will be installing antennas for the External Wireless Communication (EWC) system. That task is expected to take about two and a half hours.

Feustel will work on routing the cables to which it will connect while Chamitoff sets up the antenna. Chamitoff will first remove two handrails on Destiny and replace them with EWC handrails, which have the antennas integrated. Each handrail is held in place by two bolts. Once the antenna handrails are installed, Chamitoff will connect two power cables, and Feustel will connect three more and store two additional cables for future use. Feustel will wrap up the first spacewalk of the mission by preparing tools and equipment that will be used in the second and third spacewalks.

The crew members for space shuttle Endeavour's STS-134 mission are Commander Mark Kelly, Pilot Gregory H. Johnson and Mission Specialists Fincke, Chamitoff, Feustel and European Space Agency astronaut Roberto Vittori. During the 16-day mission, Endeavour and its crew will deliver the Alpha Magnetic Spectrometer (AMS) and spare parts including two S-band communications antennas, a high-pressure gas tank and additional spare parts for Dextre, a two-armed robot, to the International Space Station (ISS).

The shuttle crew announced the successful attachment of the $2 billion, 15,251-pound AMS atop the Starboard 3 segment of the truss of the ISS. The truss is to be the home of the instrument for the life of the station, through at least 2020. The instrument is expected to see 25,000 cosmic particles a second and can downlink six megabits of data per second. The AMS project involves 600 scientists and technicians, 56 institutions and 16 countries. Following initial checkouts, the team members in mission control were quickly able to see a vast amount of data from the detectors already.

Massachusetts Institute of Technology Professor Samuel Ting, AMS principal investigator, congratulated crew members by radio from the station flight control room in the Mission Control Center. He thanked them for the safe delivery to the station and said their work has "taken us one step closer to realizing the scientific potential of AMS."

Experts on the ground continue to perform analysis based on images taken from the station of Endeavour's thermal protection system during the backflip maneuver while the shuttle approached the station, according to information released NASA. The teams are making plans to be able to do a focused inspection of Endeavour's heat shield on Saturday, and a final decision on whether the inspection is required or not is expected this weekend.