Just a reminder that space shuttle Discovery is scheduled for launch on Saturday. It will be the second test flight for the space shuttle after Columbia’s destruction during re-entry.
During the first test flight, the same problem that eventually led to the Columbia disaster surfaced again. The foam piece didn’t hit the orbiter though and it returned safely to Earth. But the events called for more research and more improvements to the external fuel tank.
During this mission, there will be an experimental space walk with an extension to the orbiter’s robotic arm to see if they can use the new device should they need to repair the shuttle during future missions. If things go wrong during the launch, the astronauts will be able to go aboard the ISS if the orbiter is not safe to return to Earth.
The space shuttle will retire in 2010, but the ISS is not finished yet. So if things go according to plans, NASA wants to make about 15 flights to the ISS to finish it and they’re also considering a last service flight to the Hubble space telescope. When visiting Hubble, it’s impossible to use the ISS as a final solution in case the orbiter is damaged. The idea is to use the robotic arm extension they’re testing during STS-121 and try to repair the shuttle’s heat shield.
At the time of writing, there’s about 60% chance they’ll need to scrub the launch due to the weather.