Herschel and Planck will be occupying our attention late next week, but before then, Hubble once again takes centre stage.
Servicing mission 4 (SM4) will launch on Monday from Cape Canaveral (2pm EST) this coming Monday (May 11th). The shuttle Atlantis is performing the mission. There will be another shuttle on standby, acting as a lifeboat because the astronauts have no other means of escape.
The team will be giving Hubble quite an overhaul. They will be replacing a unit the controls Hubble’s communications with the onboard science instruments. Several spacewalks will replace all six gyroscopes and install new batteries. This life-extending repair mission also involves new guidance sensors, thermal insulation and a new de-orbit mechanism for when Hubble is moved at the end of its life. It is hoped that the whole exercise will give Hubble another 5-10 years delivering science.
The astronauts will also try to repair Hubble’s out-of-commission instruments, the Space Telescope Imaging Spectrograph (STIS) and the Advanced Camera for Surveys (ACS). STIS stopped working in 2004 and ACS failed in 2007. Brand new intsruments Wide Field Camera 3 (WFC3) and the Cosmic Origins Spectrograph (COS) will be installed. WFC3, is a visible, infrared and ultraviolet light camera. It should improved the sensitivity of Hubble some 10-30 times.
It is perhaps most interesting to note that if the mission is a total success then Hubble will literally be better than it has ever been! It would have six functioning scientific instruments as well as brand new stabilisation and operational components. Not bad for an observatory that is now older than the undergraduates coming into our astrophysics degree programme.
Fingers crossed for Monday!
Orbiting Frog 
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