STUC REPORT (Sept. 1994)
The Space Telescope Users Committee met on September 8-9, 1994, at STScI.
The STUC met jointly with the Servicing Science Working Group (SSWG)
on the first day to review the project status, budget, and prospects
for long-term operation of the spacecraft. The second day was concerned
largely with interaction of HST users with STScI.
With regards to material presented jointly to the STUC and SSWG, we
summarize as follows:
1. The HST project manager presented a somber status report on flight
spares for the 1997 refurbishment mission, as well as the long-term plans for
developing advanced spare components (fine guidance sensors, batteries,
solid-state data recorders, gyros, and so on) that would be required to
ensure operation of HST over its full 15-year mission.
The recent budget cuts applied to the project have essentially curtailed
all work on second-generation flight spares, leaving the project with
a small inventory of parts on hand to service any component failures that
may occur prior to the 1997 mission. The project also reported that
additional 10% budget reductions have been requested from 1996 on.
The project could not identify additional savings to be obtained
without resorting to a number of options that the STUC considers to
be extremely unattractive. These include waiving the HST Level I
requirements, terminating the Advanced Camera, reducing the data analysis
money by greater than 50%, and so on.
We find that at the very minimum, the HST project is not being allowed to plan
sensibly for long-term support of the 15-year mission due to the projected
shortage of money required to develop and support the hardware required.
We are furthered concerned that if component failures on orbit continue as
they have in the past, operation of the spacecraft more than a few years
into the future may be at serious risk. We further find this situation
remarkable, given 1) the investment made to the program so far, 2) the
success of the repair mission, 3) the demonstrated performance of the
repaired telescope, all leading to 4) the keen interest of the public in
the recent discoveries made by the repaired telescope.
The STUC has the distinct impression that the perception still exists, both
within NASA and without, that the HST budget can be further reduced
without seriously jeopardizing the future scientific returns from HST.
We are surprised by the persistence of this perception, given that none
of the six reviews of the project budget conducted so far this
year (one by the STUC itself) have been able to identify excess moneys
or savings to be obtained that did not have an adverse effect on the
operation of HST.
2. The STUC was briefed on the current plans to expand the role of the
STScI in NASA's educational and public outreach activities and views the
STScI role as an important way to disseminate to Congress, NASA, and the
general public the remarkable scientific results now being obtained in
spite of a dangerously tight budget. The STUC is willing to contribute
to this effort in any way that it can.
3. The STUC commends the Project on restoring the Advanced Camera to the
program and issuing an AO to which all qualified proposers may respond.
However, we are concerned that at the level of funding envisaged, the
resulting instrument may not be a significant advance over WFPC-II; in this
case we feel that the question of proceeding with funding for the AC as
opposed to other pressing HST needs should be carefully examined. We
strongly support efforts to enlist funding support form other individual
nations or groups to enhance the performance of the AC. We note that the
``Frontiers of Space Imaging Study'' clearly identified the Advanced Camera
as a means to enhance and ensure continued scientific returns over
the lifetime of the HST mission, a point of view that we endorse.
4. STIS and NIC remain on schedule and budget for the 1997 mission.
The project clearly understands that withholding money from either
instrument at this late stage will ultimately only result in delayed
deployment of the instruments and larger long-term costs. We understand
that with modest effort, it may be possible to equip STIS with additional
optical and UV filters. This may be an attractive ``insurance'' option
for providing some UV, or even optical imaging capability, should FOC or
WFPC2 fail prior to deployment of the Advanced Camera.
We encourage the project and STIS team to investigate this option.
With regards to material presented solely to the STUC, we
summarize as follows:
1. The STUC was very impressed by both the execution and the high quality
of the scientific data that came out of the HST observing campaign during
the impact of the fragments of comet Shoemaker-Levy 9 with Jupiter in July
1994. We commend the STScI and all of the individuals involved. Of
particular note was the organization beginning with the call for proposals,
through the mini-TAC review and selection, and the subsequent prompt funding
of investigators which ensured adequate planning and preparation.
This latter contributed not only to the high quality of the results but
also to their prompt dissemination to both the public and the astronomical
community. This experience should provide a model for future HST
observing campaigns.
2. The STUC notes a minor breakdown in communications regarding the
completion of on-orbit characterization and calibration of the scientific
instruments following the successful repair mission. In one particular
example, GHRS side 1 data obtained through mid-summer 1994 were processed
in the pipeline using pre-repair mission theoretical sensitivity curves, yet
users of this instrument were not directly notified when the on-orbit
calibration files became available. This information was duly placed in
STEIS (dated July 20, 1994), but it is clear that the members of STUC (and
probably most users) do not browse in STEIS unless notified of the need to
do so, preferably by e-mail. In general, we ask that STScI alert observers
upon receipt of their observations of any outstanding calibration problems.
3. We reviewed the plans for evaluating Cycle 5 proposals, and note that
the number of panels has expanded from 6 to 8. We note that the division
of proposals into various categories, while necessary, is somewhat arbitrary
and should not in any case be used as criteria for dividing telescope time
among the various sub-fields of interest. STScI has expressed its goal
of encouraging the TAC to allocate time in an attempt to define the best
science program overall, regardless of the mix of problems, and we encourage
this approach. We also commend STScI for changing the allocation from
spacecraft time to orbits for Cycle 5, as well as for implementing greatly
simplified proposal forms.
4. We commend STScI for development of the PRESTO and POSS programs
to assist observers with development of their Phase II proposals
and reduction of observations once their observations have been obtained.
We find it attractive to be able to interact with a small group of
individuals for the wide variety of problems that may arise in the
planning and reduction of observations. We especially endorse having a
responsible PhD level person (with associated support staff) as being
THE contact for any given program. At the same time, we strongly support
the creation of a single database structure where the status of any proposal
or problem is tracked by the system itself, rather than the memory or
availability of any single person. It is extremely important to ensure
that programs do not ``fall through the cracks'' at any stage of their
implementation. Portions of this database should be available to the
outside users, with due regard to the security of the individual GO proposal.
A key aspect of the POSS approach is the analysis ``hotseat,'' which
provides a constantly available and monitored point of contact to STScI.
We recommend adoption of a hotseat phone or email contact by the PRESTO
program, and all other STScI programs involving extensive contact
or interaction with HST users. We also urge that all such hotseat or
general points of contact be clearly posted as an ongoing feature in each
STScI Newsletter issue.
5. The STUC is also concerned with having the best scientific advice
available for preparation and analysis of the observations.
In short, understanding what an observer is attempting to accomplish
and forestalling problems will in many cases require interaction
with STScI staff capable of understanding both the technical and
scientific aims of the proposals. We thus encourage involvement of the
STScI research staff in both the PRESTO and POSS programs.
6. We suggest that STScI clarify the definition and utility of dark-time
(that is the portion of the orbit during which the spacecraft is within
the earth's shadow) for programs that require the lowest backgrounds.
This has become especially important now that users must fill entire orbits.
We wish to know under what imaging and spectroscopy conditions dark-time
should be requested, and suggest clear instructions be added to the
Phase II handbooks. Similarly, we recommend that STScI work with T. Ake
from GSFC to implement a low particle background scheduling algorithm for
those programs for which this is an important requirement, along with the
relevant documentation and instructions.
7. We were pleased to see that the STSDAS group continues to upgrade this
software package in a time of decreasing man-power, and were pleased to see
their cautious approach in converting (parts of) STSDAS to a C or C++
environment, avoiding the many pitfalls that other observatories have
encountered in similar transitions. We urge that the STSDAS group be able to
continue their important work, as many HST users depend on this software
package as their sole environment to reduce and analyze HST data.
