By Arun Kumar
Washington : Indian American astronaut Sunita Williams prepared to stay extra two days in space as experts on earth pondered how best to repair space shuttle Atlantis that would take her back home.
Williams is now expected to return June 21 instead of June 19 as US space agency NASA has added two days and a fourth space walk to the mission to repair a small tear in a thermal protection blanket near the shuttle's tail.
Ten astronauts on board the International Space Station (ISS) that has been Sunita's home for the last six months had some fresh moments of anxiety Tuesday due to a false fire alarm on the station as sensors on the shuttle registered what NASA believed were false impacts on the wing heat shield.
Several ways were being studied to fix the blanket, which peeled back during launch to expose a small triangle of underlying layers that could be damaged by heat when Atlantis returns to earth, said John Shannon, deputy shuttle programme manager.
NASA may have a space walking astronaut go stitch the blanket back together with stainless steel string, if that proves to be the strongest repair. "Once we put it down, we would like it to stay down," he told media at the Johnson Space Centre.
A routine final heat shield inspection will be conducted near the end of the mission and would reveal a problem if there is one, Shannon said. NASA has not decided whether to attempt the repair to the heat shield on Atlantis' tail section on the third space walk Friday or the unplanned fourth outing on Sunday.
"We don't want to re-enter until we've done this," said John Shannon, who chairs the NASA mission management team. "I don't want to take a risk of damaging flight hardware, when we have something that looks easy to do. So it was a pretty easy decision to make."
Shortly after Friday's launch, the Atlantis crew noticed a 6-by-4-inch gap in the fabric heat shielding that stretches over the top of a manoeuvring rocket on the tail.
The repair attempt will enlist two astronauts positioned on the end of the shuttle's robot arm. The mechanical limb will place them close enough to the tail damage to push the fabric back in place and possibly pin or sew it, Shannon said.
Meanwhile, a new pair of electricity-generating solar panels were unfurled on the space station Tuesday. Shuttle astronauts Jim Reilly and Danny Olivas had installed the panels forming part of a large metal truss Monday during the mission's first space walk.
The 240-feet-long wings had been folded for more than six years due to delays in space station construction while NASA recovered from the 2003 Columbia disaster in which Indian-born Kalpana Chawla and six other astronauts perished.
On Wednesday, astronauts Patrick Forrester and Steven Swanson will make a second space walk to set up a rotary joint that will allow the new solar panels to track the sun and possibly help retract an old solar panel that is now in the way of the new panels.