A report commissioned by the U.S. Congress says NASA should send a space shuttle mission, not a robotic one, to repair the Hubble Space Telescope. The panel of experts also says the U.S. space agency should consider launching the manned mission as early as possible after the space shuttle is deemed safe to fly again.
A panel of scientists and engineers appointed by the U.S. National Academy of Sciences says NASA should fly one final space shuttle servicing mission to the Hubble Space Telescope to repair and upgrade the observatory and prepare for its eventual de-orbiting.
Panel chairman, Louis Lanzerotti, a consultant with Lucent Technologies says the committee assessed that it's important to service Hubble as soon as possible.
"Given the intrinsic value of a service to Hubble mission and the high likelihood of success for a shuttle-servicing mission the committee concludes that such a mission is worth the risk," said Mr. Lanzerotti.
The Hubble telescope was launched in 1990 and provides images of the deepest realms of outer space. Engineers designed the telescope to be serviced regularly by astronauts.
A mission to repair and upgrade the Hubble was scheduled for 2006. NASA administrator Sean O'Keefe canceled it after the loss of Shuttle Columbia and its seven crewmembers in February 2003 saying it was too risky. Instead, NASA is planning to fly an unmanned robotic mission to service the Hubble.
The report released Wednesday says there are several limitations to any robotic servicing mission. According to panel member Joseph Rothenberg, president of Universal Space Network, it is unclear whether NASA could develop an unmanned mission in time to save the Hubble.
"Our report concludes that the Hubble is important and it's important to try and save it," he added. "The Hubble is also degrading, both the gyroscopes and the batteries, and the time of that degradation has a variance on it that could be as early as three years until it could stop doing science to a little over five years. The development time required for the robotic mission is far longer than the project currently has in their budget and would not meet the time to service it."
NASA says it is aware that the 39-month time frame to develop a robotic mission is short, but believes it to be feasible. Additionally, NASA argues that by designing a robotic service mission for the Hubble it will gain more experience in this type of unmanned flight. This experience is crucial as the space agency moves ahead with plans for the Hubble's successor, the James Webb Space Telescope, which is scheduled for launch in 2011.
NASA also remains concerned that a shuttle mission to the Hubble puts the spacecraft and crew at more risk than a mission to the International Space Station. This is partly because astronauts would not have the safe haven of the space station if a potentially dangerous technical problem arose after liftoff. But panel member Roger Tetrault, who also served on the Columbia Accident Investigation Board, says the safety risks of a shuttle-servicing mission compared to those associated with a mission to the space station are very small.
"Given the significant benefits that there appeared to be with regard to human knowledge based on fixing and servicing the Hubble it appeared to us to be worth that incremental risk, which was not large," said Mr. Tetrault. "If one assumes that the risk of a shuttle to go to the International Space Station is worth the risk we also believe that it's worth the risk to go to Hubble."
The National Academy of Sciences panel concludes that the value of a serviced Hubble telescope, which would continue to provide valuable scientific data through 2011, combined with the high likelihood of success for a shuttle servicing mission outweighs the low level of risk inherent with any shuttle mission.