Humans will revisit the Moon by 2019 and then touch down on Mars a decade later, according to a new NASA road map issued by President Bush. However, two days after the president’s 14 January announcement, NASA Administrator Sean O’Keefe, citing safety and budget concerns, canceled the space shuttle’s $600 million final service mission (SM-4) to the Hubble Space Telescope. Without a service mission, the HST is expected to last only until about 2007, chopping two years off its anticipated lifetime. The SM-4 cancellation “was a complete shock and devastating for everyone,” says Steve Beckwith, director of the Space Telescope Science Institute (STScI) in Baltimore, Maryland, which operates the HST.
Last year, NASA appointed a six-member blue-ribbon panel to review whether the HST’s lifetime should be extended beyond 2009 (see Physics Today, Physics Today 0031-9228 56 9 2003 29 https://doi.org/10.1063/1.1620825 September 2003, page 29 ). The panel’s recommendation was a resounding yes, although members also recognized that NASA might not go ahead with SM-4. “All the astronomers I talked to assumed SM-4 would occur…. I certainly assumed that it would,” says the panel’s chair, John Bahcall of the Institute for Advanced Study in Princeton, New Jersey. “I think it is regrettable that no research scientist was involved in the decision to terminate the life of the most famous research telescope of the past 100 years.”
Ed Weiler, NASA’s associate administrator for space science, says that over the past six months the scientific community was warned many times that SM-4 may not fly. “The bottom line is that some in the science community chose to ignore the warnings given to them from scientists within NASA,” he says.
The announcement that the HST only has three or four more years of life has upset people both inside and outside the science community. Beckwith says he has received more than a thousand e-mails from people decrying the decision and even offering money. “The outpouring of support has been phenomenal,” he says, “and really very touching for all of us in the [HST] project. I think it’s rare that a science facility has generated so much public good will outside of its own user base.” Senator Barbara Mikulski (D-MD) and the council of the American Astronomical Society each issued statements calling for a reconsideration of the SM-4 decision.
Second chance?
If the space shuttle were damaged during SM-4, the only space-based recourse available to astronauts would be the Interational Space Station. However, the ISS and HST orbits are hundreds of miles apart, making that a risky fallback. A second option, having another space shuttle on the launch pad ready to conduct a rescue mission, is too expensive. “The risk to the astronauts [to conduct SM-4] is too high,” explained O’Keefe at a press conference. “As astronomers, we are not experts on safety, but we do know that Hubble plays an absolutely vital role in our field,” says Sidney Wolff, former director of the National Optical Astronomy Observatory.
In a surprise announcement on 26 January, O’Keefe stated that he had asked Admiral Harold W. Gehman Jr, who chaired the Columbia Accident Investigation Board, to review the decision to cancel SM-4 and report back to him in an “expeditious manner.” A positive recommendation for SM-4 from Gehman does not necessarily mean that the mission will be approved. “I will still be the one who makes the call,” says O’Keefe.
Hundreds of suggestions on how to keep the HST operational for another 10 years have poured into NASA from companies and the public. Two of the most popular—moving the HST into an orbit closer to the ISS or using robots to conduct a servicing mission—are impractical, says Weiler. Moreover, under President Bush’s vision, completing the ISS by 2010 takes priority over the HST.
Remaining headaches
Instruments scheduled to go on the HST may find a home on other space missions. Astronomers may submit proposals to use SM-4 instruments such as the Cosmic Origins Spectrograph or the Wide Field Planetary Camera 3, says Weiler.
One of NASA’s biggest remaining HST headaches is the telescope’s decaying orbit. Sometime in 2013, most of the HST will burn up in the atmosphere, and there’s a small chance that some pieces may hit the ground and cause damage. NASA is setting aside $300 million to be used over the next five years for finding ways to do a controlled de-orbit into the Pacific Ocean.
Until then, engineers at NASA’s Goddard Space Flight Center, in Greenbelt, Maryland, are working on stretching the lifetime of the HST’s batteries and gyroscopes, the telescope’s weak links, says Weiler. Only four of the six gyroscopes are working, and the HST requires at least three gyroscopes to keep steady. Weiler says he hopes that by 2005, NASA will have found a way to operate the telescope with only two gyroscopes—which could keep the HST going until 2008. With advice from the scientific community, the STScI is evaluating how to promote proposals that maximize the HST’s current capabilities before the gyroscopes start failing. Says Beckwith, “We have at least two more good years and we are dedicated to making those the best two years of Hubble science.”
The Hubble Space Telescope (above) will be dead in space four or more years before its successor, the James Webb Space Telescope, is launched.
The Hubble Space Telescope (above) will be dead in space four or more years before its successor, the James Webb Space Telescope, is launched.
