The Astronomy Decadal Survey

Every 10 years, a committee of astronomers gets together to solicit input from astronomers across the United States. This committee then sets forth a set of recommendations for the priorities in funding astronomy programs for the next ten years. By and large, the USA astronomy community buys into this effort, and accepts as a group the committee's recommendations as the recommendations of the consensus of the whole astronomy community.

Today (2010 Aug 13), the report for the 2010 decadal survey was released. Places to find information about it:

If you scroll down on the first page linked above, you can find the full text of the survey online for free. (I have just glanced at it, and it appears to be scanned images, at perhaps not sufficient resolution.)

So far, I've only looked at the presentation. There's not a lot surprising in here. It lists the primary driving science goals, which are things that are already the current "holy grails" of astronomy. It includes detection of gravitational waves (which is strictly a physics issue, but which can hopefully then be harnessed for astronomy), understanding the first generation of stars that caused the reionization of the Universe, understanding the Big Bang and also the present epoch of cosmic acceleration, and finding Earthlike planets outside our Solar System (but still within our Galaxy).

The funding recommendations are specific, at least for large projects. On the space side, the top priority is WFIRST, a wide-field infrared survey telescope, which would be used both for signatures of probing cosmic acceleration and for finding exoplanets (as well has being a "general use" infrared telescope that would complement the JWST-- the JWST already being under construction.)

The second priority is one I applaud: reinvigorating a previously existing NASA program of "explorer class" missions. These are small and mid-size space missions which don't have the cost of something like HST, JWST, Spitzer, Chandra, or WFIRST. Some of these missions have been extremely productive, and I'm glad to see the report listing these. I haven't read the full text for the justification of it, but I suspect the the flexibility for responding to new opportunities that come with new discoveries, together with the Explorer track record, are key.

After that are LISA, a space mission that will detect gravitational waves and really make gravitational wave astronomy possible, and then a powerful international X-ray telescope.

On the ground based side, the budget scenario is more depressing. While the presentation linked above seems to believe there is a decent chance that NASA will be able to fund the top priorities, the ground based large intiatives are more sketchy. There is this ominous statement: "In event NSF budget is as predicted by agency, there can be no new starts without closure of major facilities following senior review."

What are the new starts? Two things are listed. The first is LSST, which has been the bandwagon of astronomy for several years already. It's going to be an impressive project, an 8m telescope in Chile that will survey the entire night sky in four different colors once every four days. This is going to produce an utterly mind-bogglingly huge amount of public data-- and indeed, some of the technical challenges of LSST involve effectively dealing with all of that data. This is going to be an impressive data set that will be able to do a whole lot.

It won't however, be able to do everything. I have heard some astronomers say "the LSST will do everything". Sometimes they're theorists, but often they ought to know better. Yes, the LSST is going to be an amazing dataset that will "just do" some of what people do in special targeted projects right now. But there's a whole lot that it's not going to do by itself. I already know that there are astronomers out there (like, say, me) who are worried that bread-and-butter facilities used by lots of astronomers, especially astronomers who aren't at a Caltech or a Harvard (i.e. an institution with their own private telescopes), will be sacrificed on the altar of the LSST. (The key players in which you can be sure are going to come predominantly from institutions that also have their own private mid-size telescopes.) I really hope this doesn't have to happen. There is something called the "MREFC" -- Major Research Equipment and Facilities Construction -- an NSF budget thingy, the politics and economics of which I am clueless about. Ideally, LSST (and the other major projects) are going to be at least partially funded out of this, so that they don't have to eat up the entire NSF astronomy budget (leaving people who aren't key players on those huge projects completely in the cold).

The second major project mentioned is participating in one of the efforts to build a thirty-meter class "segmented mirror" telescope. This is a telescope like the Keck telescope, only with three times the diameter. Whereas the LSST will be surveying the entire night sky every four days, this giant telescope will be used for targeted observations of the most difficult targets requiring the best light-gathering power possible.

I've left out quite a number of projects in this brief driveby. Take a look at the presentation... and if you have a whole lot of time to blow, you can always read the entire report.

As astronomers always say with great optimism when one of these things come out, "it's going to be an exciting decade for astronomy." I have to admit, though, that with ongoing financial crises that don't seem to be recovering as fast as we'd hoped, coupled with the sure knowledge that in coming decades there's going to be ever more economic, political, and humanitarian turmoil as a result of anthropogenic climate change, that I won't be surprised if over the the public starts to lose patience with pure science in the face of increasingly urgent crises (that are upon us because we spent so much time ignoring science).

Update: for a more thorough summary, see what Julianne has written at Cosmic Variance here, here, and here.

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