Sunday, September 16, 2007

Beyond Einstein redux

You may recall a rather detailed discussion last November of NASA's Beyond Einstein program back here. In a nutshell, NASA was looking at a number of very interesting space missions related to astrophysics and cosmology. But because of the foolish emphasis being placed on manned missions to the moon and (eventually) Mars and the multi-billion-$ cost of such missions, it remained to be determined whether enough money would be left over for even a few of the science missions.

Among the proposed science missions, there were two that were well along in the planning stage – LISA (to detect and study gravitational waves), and Constellation-X (a powerful X-ray observatory to be used for studying black holes and hot gas in galaxy clusters).

In addition, there were three other projects less far along in planning: a dark energy probe, an inflation probe, and a black hole finder.

In order to prioritize and choose among these missions, the Powers That Be decided to ask the National Research Council to evaluate the various missions and report back. In April Steinn SigurĂ°sson at Dynamics of Cats provided an interim report on the occasion of a meeting of the committee given the assessment task.

On September 5 an answer came back from the NRC:

'Beyond Einstein' Research Should Begin with Mission to Study Dark Energy
NASA and the U.S. Department of Energy should pursue the Joint Dark Energy Mission (JDEM) as the first mission in the "Beyond Einstein" program, according to a new report from the National Research Council. Beyond Einstein is NASA's research roadmap for five proposed mission areas to study the most compelling questions at the intersection of physics and astronomy. The committee that wrote the report added that another proposed mission to detect gravitational waves using the Laser Interferometer Space Antenna (LISA) should eventually become the flagship mission of Beyond Einstein, given that it is likely to provide an entirely new way to observe the universe. However, LISA needs more testing before a launch can be planned, whereas the Joint Dark Energy Mission is ready now for a competitive selection of mission concept proposals.

So it appears that LISA and JDEM are at least still getting serious consideration for eventual mission funding. But don't forget that this is merely a recommendation to NASA and the Department of Energy (the agencies that must actually fund the projects). The projects could easily be blocked or delayed by the agencies themselves, the Executive Office of the President (especially by budget officials), or Congress.

Note that JDEM, the dark energy mission, is actually three competing proposals, among which it will still be necessary to settle on one:
So far, three specific mission plans have been studied in this area: the Supernova Acceleration Probe (SNAP), the Dark Energy Space Telescope (DESTINY), and the Advanced Dark Energy Physics Telescope (ADEPT), but the eventual JDEM could be any one of the three or be based on a different option altogether. The committee found that the underlying technology for a dark energy mission is, for the most part, in the prototype phase, and will require less development than most of the other missions. The potential gains for JDEM also outweigh its scientific risks, such as the possibility that the mission may not provide substantial insight beyond that provided by telescopes on the ground. The report recommends that NASA and DOE proceed immediately with a competition for mission proposals that will investigate the nature of dark energy with high precision.

LISA is also recommended for continued development. It's status is somewhat different in that the project is being funded jointly between NASA and the European Space Agency (ESA). And further, future plans depend on what is learned about the technology (an ambitions space-based interferometer) from a preliminary project called LISA Pathfinder, which is to be launched in 2009.

The NRC recommendation leaves the three remaining projects in limbo:
[T]he three elements of Beyond Einstein that are not being recommended for immediate implementation are still important endeavors that should receive continued support. The committee found that because the Constellation-X mission is a general-purpose x-ray observatory capable of broad contributions to astrophysics, it should be funded and assessed in a broader context than the Beyond Einstein program. The Black Hole Finder Probe and Inflation Probe missions will also make important scientific contributions; however, because of scope and technical readiness issues, they fell behind JDEM and LISA. The committee recommended that Constellation-X, Black Hole Finder Probe, and Inflation Probe receive continued support to prepare them for the next decadal survey of astronomy and astrophysics.

Additional news reports have focused mainly on the dark energy mission, for example here, here, here.

Steinn, of course, has some enlightening commentary here, here, and especially here.

The next shoe to drop is a reply from NASA, which could come at any time. It should be noted that there are possible ways and means to squeeze in some of the scientific missions which did not get recommended at this time, but that will require continued lobbying and can only be speculated on now. And everything goes up for grabs again, after January 20, 2009. One step at a time.

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