Considering Hubble’s fate: a followup
by Jeff Foust
|The panel proposed developing a new orbiting telescope to replace Hubble by the end of the decade if no future Hubble servicing missions are planned.|
One key question the panel grappled with is whether an additional servicing mission, SM5, is worthwhile from a scientific standpoint. A number of astronomers submitted comments to the panel calling for such a mission, proposing a number of specific surveys that Hubble could perform during its extended mission. On the other hand, however, some astronomers expressed concerns that funding used for SM5 and extended Hubble operations, which could be several hundred million dollars, could drain money away from other astronomy spacecraft programs.
The panel didn’t make a judgement on the value of performing SM5, but did suggest a way to determine its merit. The panel said that NASA should issue an announcement of opportunity (AO) for scientific work to be performed using Hubble after SM5, using either existing or new instrumentation. The winning proposal would then be evaluated against other science missions in the Discovery, Explorer, and similar programs to determine its overall merit. This method, the panel concluded, would ensure good science, either using Hubble or other spacecraft, would be funded.
Another way to carry out SM5 would be when the time comes to plan deorbiting the telescope. NASA is currently considering two ways to do this: have an automated propulsion module attach to the telescope, or have a shuttle servicing mission carry out the task. The latter is preferable from the standpoint of the panel, since the same mission could also be used to perform final upgrades to the telescope to permit it to continue operating for several more years.
|“When Hubble finally reenters the atmosphere, it will be kind of a sad day for a lot of us Hubble-huggers,” said Grunsfeld.|
One interesting section included in the report dealt not with Hubble but with its successor, the James Webb Space Telescope (JWST). Based on past history, the panel expressed considerably skepticism about NASA’s plans to launch JWST in 2011. The panel noted that for NASA’s four “Great Observatories”—Hubble, Compton, Chandra, and SIRTF—the average time between issuing the AO for instruments to the launch of the spacecraft is nearly16 years. With the AO for the JWST instruments published in late 2001, the panel noted that if JWST meets this average, the spacecraft will not launch in 2017. Indeed, the spacecraft’s launch has already slipped a few years from late this decade until 2011. This poses a concern for astronomers who desire to have an overlapping period where both Hubble and JWST are simultaneously operating.
John Grunsfeld, a NASA astronaut and self-proclaimed “Hubble-hugger”, told attendees of the annual International Mars Society Conference in Eugene, Oregon, last week that he thinks that, one way or another, Hubble will be kept operational until 2010 to 2012. “When Hubble finally reenters the atmosphere,” he said, “it will be kind of a sad day for a lot of us Hubble-huggers, but you can’t deny that it has performed a tremendous amount of science.”