Shuttle astronauts would be just as safe going to the Hubble Space Telescope as they would be on a mission to the International Space Station, according to two leaked documents reportedly written by NASA engineers.
The surfacing of the documents has reignited the debate over NASA’s controversial cancellation of a 2006 mission to service and upgrade Hubble, mainly on the grounds of astronaut safety.
“Those documents certainly undercut the public position of the agency,” said Garth Illingworth, an astronomer at the University of California who advises NASA on space science, in a New York Times report. Members of the US government’s House Science Committee have received copies of the documents and are expected to discuss them at a meeting on Thursday.
The Columbia Accident Investigation Board (CAIB) recommended that future shuttle missions have the capability to inspect and repair any problems while in orbit. When NASA Administrator Sean O’Keefe cancelled the Hubble mission – the only one planned that was not headed for the space station – he cited the directive and said such a mission would require a one-of-a-kind contingency plan.
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“NASA has chosen to use the space station as a platform to accomplish [on-orbit inspection and repair], thus effectively ruling out missions which do not go to the space station,” CAIB board member Sheila Widnall told New Scientist.
Fully autonomous
However, both the CAIB report and the leaked documents suggest using the space station in this way may not in fact resolve the safety issue. For example, shuttles bound for the space station could develop problems before they reach their destination or fail to dock or undock properly.
“The ultimate objective should be a fully autonomous capability for all missions,” reads a CAIB recommendation from June 2003.
One of the reports, leaked to the New York Times, says astronauts on a Hubble servicing mission could use another shuttle as a rescue vehicle if needed. This would be possible if the Hubble mission were scheduled just before another shuttle mission, as the second mission could be redirected.
The same report questions whether the ISS is truly a “safe haven”, as the station’s ability to house extra crew members hinges on a Russian life-support system that “has not been shown to be very reliable”.
The reports further argue that the shuttle also has more flexibility to turn around in the Hubble orbit so that its leading edges are better shielded from micrometeorite hits.
NASA’s decision to cancel the servicing mission, made on 16 January, sparked so much protest that agency agreed two weeks later to an outside review of the judgment. This review, by CAIB chairman Harold Gehman, has yet to be completed, but in any case NASA has asserted it has final say over the mission.
