NASA announced today that it will send a crew of astronauts to repair the aging Hubble Space Telescope, reversing a previous agency decision that such a shuttle mission was too dangerous for the expected scientific payoff. But the $350 million servicing mission will make it even harder for NASA to fund future astronomy missions.
Speaking this morning at Goddard Space Flight Center in Greenbelt, Maryland, before an appreciative audience of scientists and engineers, NASA chief Mike Griffin said he was happy to abandon a "troubling, troubled, and unpopular decision" by his predecessor, Sean O'Keefe. "It's fantastic," says Mario Livio, an astronomer at the Space Telescope Science Institute in Baltimore, which operates Hubble for NASA. "Clearly, we are ecstatic." The mission, scheduled for May 2008, is expected to extend the telescope's operating life well into the next decade.
Repaired four times since its launch in 1990, Hubble was scheduled for a final servicing flight in 2004 when the returning Columbia space shuttle disintegrated over Texas on 1 February 2003. The following year, then-NASA chief Sean O'Keefe canceled the mission because of safety concerns. Hubble circles Earth in a different orbit from the space station. If the astronauts were to face an emergency during a Hubble visit, the crew would not be able to reach the space station and wait for rescue by another orbiter. O'Keefe argued that the possible loss of lives was not worth the additional scientific results from Hubble.
But a chorus of scientists and politicians raised a ruckus, setting off a 3-year debate over its fate. Seeking a compromise, O'Keefe proposed a robotic repair mission. But a National Academy of Sciences' panel rejected that idea as technically too difficult, costly, and time-consuming, urging NASA to reschedule a shuttle repair mission and to charge nonscience programs for part of the cost.
Taking over from O'Keefe in April 2005, Griffin pledged to abide by those recommendations if subsequent shuttle flights demonstrated that the fleet could be operated safely. "What's different now is that we have three flights under our belt," says Goddard Director Ed Weiler.
Griffin's decision means that NASA will spend most of its astronomy budget on three major missions--the Hubble servicing flight, construction of the James Webb Space Telescope, and the Stratospheric Observatory for Infrared Astronomy (SOFIA). Technical troubles, schedule delays, and cost overruns plague the latter two. But Weiler says that the Webb is back on track after a rough couple of years, while SOFIA--which Griffin initially canceled only to revive in July--is slated to begin operations in 2009.
Those large projects leave little room for smaller or future missions. For example, NASA halted work earlier this year on the extrasolar planet-seeking Space Interferometry Mission (SIM) in order to cover SOFIA's cost overruns. Those pressures worry some astronomers, who fear that the three missions will limit new efforts.
Weiler is more sanguine. "Is the astronomy program with just [Webb], Hubble, and SOFIA a good astronomy program? You betcha," says Weiler. While he acknowledges that there is a gap in smaller missions for the next few years, he notes that the cost of building the Webb will peak in 2008 and then decline over the next 5 years. "The big issue now is what to do with that wedge."