Washington: The International Space Station grew further on 12 June when two astronauts from the US shuttle Atlantis ventured out for the first space walk to connect a new 15.9 tonne truss that will increase the power capability of the International Space Station (ISS).
The two mission specialists John Danny Olivas and Jim Reilly, emerged from an airlock on the station at 4:02 pm (2002 GMT) in the first of three planned space walks, according to the US space agency NASA’s television broadcast.
Their job was to make power, data and cooling connections on a new 16-tonne truss segment containing solar panels. The enormous truss was attached before the space walk with the help of the station’s giant robotic arm in a delicate maneuver.
The truss’s solar arrays -- which have a span of 73 meters (240 feet) -- will dramatically increase the International Space Station’s (ISS) power generation, with a potential of up to 14 kilowatts of power. The power capacity will help serve new science modules from the European and Japanese space agencies planned for the future.
With mission control in Houston providing direction down to the smallest detail, the two astronauts have to remove bolts and release locks that kept the structure in place during the shuttle launch.
The spacewalk was scheduled to wrap up about 0230 GMT. The solar arrays, folded up like an accordion, are to be unfurled on Tuesday.
John Shannon, one of the mission’s directors, said in a briefing later on Monday that NASA would extend the planned 11-day mission by two days and send crew members out on a fourth spacewalk in addition to the three scheduled ones.
The space walk was slightly delayed due to problems with “gyros” that control the orientation of the station, which flight controllers managed to repair, NASA said.
The shuttle -- on its first mission of the year -- docked with the ISS Sunday, after performing a dramatic backward somersault in space.
NASA officials were also weighing whether the astronauts might be asked to repair damage to a thermal blanket that tore during liftoff.
The shuttle suffered a four-inch (10 centimeter) tear to the thermal blanket and small pieces of foam broke off from its external fuel tanks after it blasted off from the Kennedy Space Center in Florida Friday.
Digital photographs of Atlantis’s underbelly were to be transmitted to Texas and examined to make certain that its heat-protective exterior is in good shape for its return to Earth.
Lift-off damage is a concern after the February 2003 shuttle disaster. The Columbia craft disintegrated as it returned to Earth due to breaks in its heat shield caused by foam insulation peeling off its fuel tank and striking a wing during the launch.
All seven astronauts aboard perished and the shuttle program was put on hold for nearly two and a half years while the space agency sought to overcome the problem, modifying the external fuel tank and setting procedures to check the heat shield while in orbit.
NASA has played down concerns over the damage to Atlantis. Shannon earlier said the damage is in a spot not exposed to the highest heat as the shuttle breaks through Earth’s atmosphere.
Atlantis’s 11-day mission STS-117 is the first since hail damage to the spacecraft in a freak storm forced NASA to scrap a March lift-off.
The ISS is a key stepping stone for preparing manned missions to Mars. NASA plans at least 13 more shuttle missions to finish the 100-billion-dollar station by 2010, when the agency retires its three-shuttle fleet.