From: NASA Advisory Council
Posted: Monday, February 25, 2002
February 25, 2002
Letter to Origins Director Dr. Anne Kinney from Dr. Alan Dressler, Chair of OS
Dear Dr. Kinney;
The Origins Subcommittee met in Pasadena, California on February 25, 2002. We were pleased to be briefed by you and Ed Weiler by telecon on the progress of the Astronomical Search for Origins theme and about the strong and growing level of support for the Origins theme in the FY2003 Federal budget. As you know, this meeting was introductory to a first meeting of the full team which will prepare the 2003 Origins Roadmap as part of NASA's Strategic Planning process. I am pleased to report that we made substantial progress on the Roadmap on February 26-27, and want to commend to you the excellent preparation by Mike Devirian, Chas Beichman, Phil Crane, and the JPL staff, who put the Roadmap meeting together.
Phil Crane reviewed the status of Origins missions, which contained good news and not-so-good news. On the positive side we heard that GP-B is making good progress toward a possible launch this calendar year and that SIM had made significant headway toward meeting its technical milestones. We learned that SOFIA has been keeping close to the revised schedule set last year, that the NGST prime contractor would be selected soon, and that TPF will shortly select two architectures for further development. Phil also told us about the selection of 6 programs, winners of last year's NRA, which will study various aspects of planet finding and characterization – the road to TPF – all of which sounded extremely interesting. On the other hand, we heard about the further postponement of SIRTF to early 2003, the probable re-scoping of Starlight to a ground program, and the cancellation of FAME, which the OS particularly regrets. Based on Phil's report, we would like to request these detailed briefings at our next meeting: (1) a thorough description of the winning NGST proposal; (2) a description of the reformulated Starlight program; (3) a presentation of the two architectures selected for TPF; (4) a report on progress in the Data Cycle part of SOFIA; and (5) a description and status report on GP-B – an SEU mission that the OS would like to learn more about.
Ed Cheng (GSFC) brought us up-to-date on the progress with WF-3, the panchromatic imaging system for the Hubble Space Telescope being readied for SM-4, now scheduled for February 2004. We were greatly encouraged by the way WF-3 has stayed on schedule and within budget. All aspects of the development are going extremely well, with the exception of some concerns with the 1K x 1K HgCdTe IR array. The project is working on issues of read noise and quantum efficiency that could significantly compromise performance of WF-3 in the near-IR, but there is progress on solving these problems with Rockwell, the supplier of the detectors. With significant schedule and budget contingency remaining, Ed was optimistic that the IR arrays will rise to the same high expected level of performance that has been achieved with the Marconi CCD arrays for UV-optical observations. The astronomical community can look forward to a substantial boost in HST capability with the installation of WF-3.
Ed also reported that there had been some discussions regarding possible guaranteed HST observing time for the SOC that continues to provide excellent guidance to the WF-3 project. If you would like advice on this matter, we would be pleased to hear a presentation on this issue at a future meeting
Mike Werner briefed us on the status of SIRTF, which reached the major milestone of completion of the CTA. We understand that a “wiring anomaly” problem will probably disable part of the MIPS, but, as in the case of the long-low filter delamination, we agree that the scientific impact should be acceptable and certainly support the decision not to open the dewar for an attempted repair. The scientific potential of SIRTF remains enormous and, despite the slip in schedule to a projected launch on January 9, 2003 (mainly as a result of a schedule slip in the delivery in flight software), the OS remains very enthusiastic and optimistic about the huge scientific payoff SIRTF will soon deliver.
As you know, we have shared your concern that the Origins program is dominated by large, difficult “strategic” missions such as SIM and NGST, and have hoped that smaller missions would be undertaken that provide both science and technology that is critically needed in the program on a 5-10 year timescale. It was, then, a great pleasure to hear from Bill Borucki about the plan for the Kepler mission, which has been chosen as a Discovery mission for a new start next year. By monitoring 100,000 stars for transits, Kepler will provide unique data on the frequency of planets down to Earth-size, information that will be essential for the planning of TPF. The OS extends its congratulations to Bill and hopes that Kepler will proceed as rapidly as possible to a successful launch four years from now.
The OS heard a summary report from Ken Johnston on the unfortunate cancellation and unrealized scientific potential of the FAME Explorer. It was encouraging to hear that Ken was continuing detector development with remaining funds and that the Navy's support of the project could continue at a sufficient level to solve some of the outstandingproblems. Ken also raised the possibility of NASA participation in Gaia or collaboration with a German mission (DIVA) whose science goals are also similar to FAME. The OS strongly endorses the exploration of these possibilities.
As part of the generally excellent astrophysics goals of FAME that are now lost, we wish to highlight those particularly relevant to the Origins Theme. These include absolute trigonometric parallaxes (fundamental distances) that would unambiguously identify the 10-100 Myr old stellar populations within a few tens of parsecs of the Sun that are prime candidates for searches of solar systems in the process of formation, as well as astrometric searches for 10-80 MJup companions around stars of all ages. In fact, FAME science would have provided a pedestal for many future Origins investigations – the precise measurement of such a fundamental property as luminosity is invaluable for a wide range of stellar evolution programs irrespective of the presence of disks and/or planets. While we realize that some of the FAME science can be incorporated within the SIM mission (and we were glad to hear from Mike Shao that such planning is underway), we expect that in the process of preparing the 2003 Origins Roadmap we will discuss further the question of how to replace the valuable science that has been lost.
The Origins Theme Roadmap
In preparation for the following meeting of the Origins Roadmap Committee, Phil Crane briefed the OS on the process that was about to begin. As we indicated to you in our telecon, the OS is concerned about how future missions such as SAFIR, which was recommended in the McKee-Taylor Decadal Survey, will be fit into the new structure of the Astronomy & Physics Division. Our preliminary thinking is that this far-IR mission and the proposed large-aperture UV-optical follow-on to HST are natural Origins missions, with primary science goals intimately entwined with the work SIRTF and NGST will do on galaxy birth and evolution and the formation of stars and their planetary systems. We completely agree with your position that the highest priority for these concepts is to develop the needed technology for them, but we still are interested and concerned about the issue of whether new missions such as these will be taken under the wing of Origins and/or the SEU initiative that we enthusiastically support, or whether they will be proposed as augmentations under the general A&P Division program, not necessarily linked to a theme. The OS sees strong advantages for having missions incorporated into the theme structure, although we are aware of the risk of not adequately supporting missions that might “fall in the seams.” We hope that over the course of preparing the Origins and SEU Roadmaps this issue can be considered carefully. We believe that the intellectual framework is important for the A&P Division and should continue to play an important role in programmatic decisions.
Finally, a somewhat related matter is the phrase “All roads lead to TPF” that we heard repeated several times during our one-day meeting. We understand that this sentence first appeared in the technology roadmap for Origins, and reflects the important goal of coordinating and directing our technical and scientific efforts to make this inspiring and very challenging goal a reality. Beyond SIM and NGST there is no doubt that TPF becomes the heart of the Origins program. On the other hand, the OS hopes that the astronomical community will not hear the message that Origins is evolving into a “planet-finding-only” theme. Although the OS acknowledges that the balance in Origins could shift after NGST, at the same time we believe that the whole Origins theme – from the first stars through the production of the chemical elements to starbirth to the formation of planets and their biological habitats – will challenge astronomers for decades to come. It is our hope that Origins will remain a program that weaves all these elements together – that is its strength – and not focus too soon on the search for other worlds, even if that is the destiny of our program in the long term. We would be pleased to continue this discussion with you at our next meeting, now scheduled for the first week of June 2002.
Alan Dressler, Chair, for the Origins Subcommittee
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