National Academy of Sciences to assist space agency in study of future alternatives
NASA has defended its decision to cancel the Hubble Space Telescope servicing mission by the Space Shuttle, and hinted that a robotic mission to extend the spacecraft's useful life is possible. Administrator Sean O'Keefe says the commitment to implementing the Columbia Accident Investigation Board (CAIB) recommendations, and not budget cuts forced by President George Bush's space exploration initiative, drove his decision to cancel the final servicing mission (SM-4).
O'Keefe says NASA is "encouraged" by preliminary assessments of alternative options for deploying instruments that would have flown on SM-4. A review of responses to a request for information on proposed life-extension mission concepts will be completed by mid-April. Alternatives being considered include a robotic mission to capture and deorbit the Hubble or boost it into a long-term storage orbit; and various levels of robotic servicing mission ranging from attaching a long-term power source to replacing systems like gyros and instruments.
O'Keefe says delaying the Shuttle return to flight to March 2005 at the earliest "dramatically" reduced the prospects that all the CAIB recommendations would be complied with in time to mount a servicing missions before the Hubble ceases to be operational. The observatory is expected to remain operational to 2007-8 based on battery life, but gyroscope life, which governs scientific operations, is more difficult to predict, NASA says. The agency is looking at adjusting the way it operates the Hubble to extend battery and gyro life, says O'Keefe.
In the face of Congressional questioning, O'Keefe has agreed to have the National Academy of Sciences assist NASA in a study of alternatives for Hubble - including an examination of the risk and value of a Shuttle servicing mission. While arguing that NASA should launch "the fewest possible" Shuttle missions, former CAIB chairman Hal Gehman has told Congress "only a deep and rich study of the entire gain/risk equation" can determine whether extending the Hubble's life is worth the risks involved.
SM-4 was the sole remaining Shuttle flight not directed to the International Space Station, which will be used as a "safe haven" in the event of orbiter damage.
GRAHAM WARWICK / WASHINGTON DC
Source: Flight International
