ORIGINS SUBCOMMITTEE (OS) MEETING
Pasadena, California
February 25, 2002
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.
Origins Missions
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.
HST-WF3
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
SIRTF
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.
KEPLER
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.
FAME
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 outstanding
problems. 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.
Sincerely,
Alan
Dressler, Chair, for the Origins Subcommittee