Hubble re-fit mission to go ahead

Physics Today: A space shuttle mission to repair the Hubble Space Telescope was given the go ahead on Friday, in a desperate attempt to keep NASA’s flagship space-based instrument up and running. An official announcement by NASA administrator Michael Griffin is expected later today. The space shuttle will visit HST in 2008, replacing the six gyroscopes that position the telescope, adding new instruments, and extending its working life to beyond 2013. The Columbia space shuttle accident caused the last service mission to be canceled as the risks of reaching the HST, which is in a higher orbit and inclination to the International Space Station--the emergency ‘lifeboat’ for space shuttle flights in case the shuttle has to be abandoned -- outweighed the benefits said Sean O’ Keefe, the previous NASA administrator at the time. New safety equipment has limited the risk involved say NASA officials, and the servicing mission has popular support among the astronaut corp, the public, and the scientific community.The HST is the most successful NASA instrument ever placed in orbit. The HST replacement, the James Webb Space Telescope, is falling behind schedule, and now not expected to fly until 2014. Extending the lifetime of the HST would allow observations at ultraviolet and near infrared wavelengths to continue, instead of ending in 2008, when the HST’s last gyroscope is expected to fail.NASA had investigated using a unmanned robot to service the HST and fit a de-orbit module to the telescope, to help with a controlled re-entry when the telescope’s orbit decayed around 2013. New orbit calculations suggest that the telescope could survive the scheduled increase in solar activity over the next fifteen years, if the shuttle boosted its orbit slightly. The extra orbit time will allow NASA to consider new ways to dispose of the HST, or retrieve it.