From the December 2004 issue

Hubble’s lot

Two experts sound off on the fight to save Hubble.
By | Published: December 27, 2004
Hubble Space Telescope
The Hubble Space Telescope is ailing, and NASA’s decision to cancel the last servicing mission remains contentious.
Whether the Hubble Space Telescope will be serviced by humans or a robot, or de-orbited is unknown but highly debated. Below, astronomer Alex Filippenko of the University of California, Berkeley, and science writer Robert Zimmerman exchange letters on this topic. Their discussion brings to light several important issues, including past decisions made concerning the telescope. In fact, the battle to save Hubble may have been lost almost a decade ago.

In “The looming death of Hubble” (November 2004), author Robert Zimmerman suggests professional astronomers immediately decided to abandon the Hubble Space Telescope (HST) and that only the public cared. He writes:

And then, even as HST was reshaping our perceptions, everyone decided to abandon it — the astronomers who depend on it for research, the politicians who revel in the reflected light of its glorious imagery, and the bureaucrats charged by the public to keep it running. Hubble was to be allowed to die and drop into the ocean. NASA would build a replacement telescope working in the infrared, and optical astronomy would return to using big ground-based telescopes alone.

The public, however, has not been so willing to bow to the decisions of the power-broker elite. Their taxes paid for Hubble; they feel it is important to have a space-based optical telescope. And they have forcefully told the decision-makers to rethink the idea of abandoning Hubble.

I would like to know the source of Mr. Zimmerman’s information. I and many other astronomers are much in favor of keeping the Hubble Space Telescope. Indeed, together with Bob Kirshner of Harvard University and Steve Beckwith, the director of Space Telescope Science Institute in Baltimore, I spoke to members of the U.S. House of Representatives on this topic in September.
— Alex Filippenko, University of California, Berkeley

I think Dr. Filippenko misinterpreted what I wrote. When I said the astronomical community was willing to abandon Hubble, I was not referring to the present situation. Today, support for keeping Hubble operating is furious and strong among almost all scientists. Many astronomers everywhere are waging an aggressive campaign to save what we all consider the greatest astronomical instrument ever placed in orbit.

Instead, I was referring to the decisions made by astronomers from the mid-1990s through the early 2000s, when discussions about designing Hubble’s replacement were underway. Although the early debates considered it essential to build an even bigger optical/ultraviolet space telescope to replace Hubble, by the late-1990s, the astronomical community had concluded it preferred replacing Hubble with just an infrared space-based capability.

In fact, the conclusions of the 1996 Dressler report (officially called “HST and Beyond”) were especially crucial. Although it recommended extending Hubble’s life, it also recommended “a much more economical style of operation beyond 2005 … with no servicing or instrument replacements after 2005, a final boost into a higher, long-lived orbit, and a possibly reduced instrument complement and limited modes of operation.” It also recommended that Hubble’s replacement work not in the optical wavelengths but in the near- to mid-infrared.

By 1998, the die was cast. The astronomical community had decided that Hubble’s replacement would be an infrared telescope. Although scientists hoped to keep Hubble operating through 2010, in my research, I can find no evidence of any effort by astronomers to either maintain it or build a replacement optical or ultraviolet space telescope beyond that year.

The 2001 “Astronomy and Astrophysics in the New Millennium” report, written by some of the most important astronomers in the world and sometimes called “The Decadal Survey,” was especially blunt: “The committee has not recommended any new moderate or major missions for space-based UV [ultraviolet] or optical astronomy for this decade.” Instead, the Decadal Survey once again recommended the completion of one final servicing mission to Hubble, followed by “reduced operating costs.”

Meanwhile, the Next Generation Space Telescope, which we now call the James Webb Space Telescope (JWST), would devote itself to the infrared wavelengths, while large ground-based telescopes using adaptive optics would handle the optical wavelengths. Ultraviolet research, which according to the survey “is impossible to observe … from the ground,” was provided no replacement after Hubble. The report conceded that once Hubble was de-orbited, such research would be impossible, “for this decade at least.”

In the dozen years I have been writing about astronomy, I have been continually baffled and confused by this situation, and I have repeatedly asked various experts about it. When I interviewed Steven Beckwith in May, he explained that the astronomical community had made a calculated, strategic decision to get the infrared telescope built first, then deal with getting a replacement for Hubble. “You have to prioritize … HST was up there, it was going to be supported for at least another decade … What [the Decadal Survey] wanted to do was to push JWST, [making it] the key number one priority,” he said.

The June testimony of John Bachall of the Institute for Advanced Study in Princeton before the National Academy of Sciences was also telling. Although he was remarkably circumspect, he also left no doubt there had been and continues to be a strong faction within the astronomical community that opposes spending any money on an optical space telescope, preferring instead to let the ground-based telescopes do the work.

In fact, it wasn’t until shortly before the Columbia space-shuttle accident that a committee of scientists, headed by John Bahcall, finally declared they wanted to keep Hubble operating past 2010. This Bahcall committee not only agreed the scheduled servicing mission to Hubble was necessary, it called for NASA to seriously consider flying an additional servicing mission — in order to keep Hubble operating until late in the 2010s. “The committee prefers a shuttle mission for this purpose because the same mission will also improve the performance of HST before it is brought down to Earth.”

Unfortunately, that committee report was too little too late.

There is an old saying: Be careful what you wish for or you might get it. By not pushing for an optical/ultraviolet space telescope to replace Hubble in 2010, and by accepting no servicing and limited operations for Hubble after 2005, astronomers left themselves vulnerable to having Hubble’s last servicing mission canceled. Consider how it must have looked to NASA Administrator Sean O’Keefe and other agency bureaucrats: If astronomers didn’t think it was necessary to service Hubble after 2005, why should it matter if servicing ended now? And why should astronomers care anyway, because they didn’t seem interested in building an optical telescope to replace Hubble?

As a result, the astronomical community, the people for whom the loss of Hubble matters the most, gave O’Keefe the very ammunition he needed to end Hubble sooner than necessary.

Now that reality has struck, and everyone knows what is about to be lost, the effort to save Hubble is strong and vibrant. To that I say, “Thank God!” I and the general public can only hope that lobbying by you and many other important scientists will provide NASA the impetus to keep Hubble operating until a replacement optical/ultraviolet telescope can be designed, built, and launched.
— Robert Zimmerman