Weighing in on the argument over whether to attempt a robotic or manned mission to repair the Hubble Space Telescope, the US Government Accountability Office (GAO) has cast doubt on NASA's estimate of a $1.7-2.4 billion pricetag on a Space Shuttle servicing mission to the orbiting observatory. This compares with the estimated $2 billion cost of a robotic repair mission.

The Congressional watchdog also questions NASA's estimate that returning the Shuttle to flight will cost more than $2 billion.

The GAO says there is insufficient documentary support for both estimates.

The US National Academy of Sciences last month urged NASA to mount another Shuttle servicing mission to the Hubble because it could be launched sooner, with a greater chance of success, than an unproven robotic mission.

The Academy added that it would also entail no more risk than a Shuttle flight to the International Space Station.

The GAO asked NASA to estimate the cost of mounting a Shuttle mission to Hubble in March 2007. The National Academy of Sciences concluded a manned servicing mission could be launched as early as July 2006, after seven Shuttle flights to the ISS, but a robotic mission could not be launched before February 2010. Gyroscope failure is expected to end the space telescope's operational life in late 2007.


Source: Flight International