The space shuttle Atlantis was poised for launch yesterday on one of the final missions to outfit the International Space Station so it can remain flying long after the shuttles are retired.
Liftoff of Atlantis and its six-man crew on the last shuttle mission of the year is scheduled for 2:28 p.m. EST (7:28 p.m. British time) from the Kennedy Space Centre in Florida. Forecasters predict a 70 % chance that the weather will be suitable for launch.
NASA plans to end the 30-year-old space shuttle program next year, bowing to long-standing concerns about safety and the expense associated with maintaining and flying Atlantis and its two sister ships, Discovery and Endeavour.
The shuttle program costs NASA about $5 billion (£3 billion) a year, and has claimed the lives of 14 astronauts. The first crew of seven perished during a launch accident in 1986 and the second died during a landing attempt in 2003 due to a heat shield breach.
The US space agency has been working to replace the shuttles with a partly reusable, capsule-style spacecraft called Orion to fly crews to the moon and other destinations in the solar system in addition to the space station, which orbits 225 miles (360 km) above Earth.
The station, a $100 billion project of 16 countries that has been under construction for more than a decade, is due to be completed in 2010. After Atlantis’ mission, five flights remain to finishing building and outfitting the station.
Atlantis is loaded with about 30 000 pounds (13 610 kg) of equipment too big to be transported by the Russian, European and Japanese cargo ships that will keep the station stocked with food, fuel and other supplies after the shuttles are retired.
“It’s been the workhorse of just getting the big parts up,” Atlantis commander Charles Hobaugh said of the shuttle in a prelaunch interview. “The station itself right now is an incredible vehicle. We just need to provide its sustainment.”
Atlantis will bring home station flight engineer Nicole Stott, the last station crew member to fly on the shuttle.
During its planned 11-day mission, the Atlantis crew is scheduled to conduct three spacewalks to install antennas, replace an oxygen tank on the US airlock and other tasks.
NASA built four pallets to hold spare pumps, gyroscopes, tanks of oxygen, nitrogen and ammonia, as well as other gear.
Two will fly on Atlantis and will be mounted outside the station during the shuttle’s weeklong visit. The final two pallets will fly on the last two shuttle flights next year.
“We’re going to warehouse parts that only the shuttle can deliver in large volume,” said Mike Sarafin, NASA’s lead flight director.
While the equipment is not needed today, NASA wants to have the critical spare parts available so the station can remain viable through at least 2015, and possibly to 2020 or beyond.
Extending the station is among the recommendations of a presidential panel that reviewed the US human space program this summer. The Obama administration is considering changes to the agency’s $18 billion budget, about half of which is spent on human space exploration initiatives.
In addition to Hobaugh, who is making his third spaceflight, the crew includes pilot Barry Wilmore, flight engineer Randy Bresnik, lead spacewalker Michael Foreman and astronauts Leland Melvin and Robert Satcher. Wilmore, Bresnik and Satcher are making their first spaceflights.