1.
Concern Over Program Funding
The chief finding of
the SRWG from its June, 2000
meeting was its alarm over the current fiscal situation surrounding
NASA’s
sounding rocket program. To this end,
the SRWG wrote a separate letter to Dr. Edward J. Weiler, NASA
Associate
Administrator, Space Science. A copy of
this letter is attached.
2.
Flight Safety and Black Brant XII Launches
The SRWG is concerned
that under many circumstances it
appears difficult, if not impossible, to launch a Black Brant 12
mission from
the Poker Flat range without one or more waivers to the current flight
safety
rules. The fact that these waivers are usually granted suggests that
some of
these safety standards may be revisited for their applicability at the
Poker
range. While it is certainly not the intent of the SRWG to compromise
safety
considerations in any way, it is hoped that a revised flight safety
process
might streamline Mission Readiness Reviews for Black Brant 12 missions
in the
future.
3.
Maximizing Observing Time
Maximizing the
observation time of a sounding rocket
instrument, be it a micro-gravity payload, an astronomy payload, or a
space
physics payload, is often crucial to the success of the mission and,
therefore,
the sounding rocket program as a whole. Observation
time is directly proportional to
altitude and
correspondingly to the combined payload mass and vehicle performance. For astronomy, planetary, and solar
observations, as well as most microgravity experiments, such missions
require
recovery and thus improved guidance systems (e.g., DS-19) and recovery
systems
(that must perform higher re-entry speeds) must be utilized to
accommodate the
higher apogee missions.
The Sounding Rocket
Working Group recognizes that the
confluence of circumstance, i.e. the development of higher performance,
lower
mass technology and the continued need for extended observation times,
is a
unique opportunity to provide meaningful guidance to NSROC on the
development
of new hardware. The SRWG urges NSROC to
aggressively pursue plans to launch payloads higher than has been done
traditionally as payload weights are lowered. For
example, many new technologies are under serious
study which improve
technical performance at a substantially lower mass, e.g. the ST5000
star
tracker system.
4. DS-19 Performance
The SRWG is concerned
with the level of quality control
implemented during production of the DS-19 that led to a recent failure
at
White Sands. We appreciate the
presentation on the DS-19 performance and believe that the problem has
been
understood. We support continued use of
the DS-19, provided adequate quality assurance procedures are followed. The DS-19 provides a means to fly higher
(longer) at WSMR, a capability keenly desired by several groups,
especially
with the potential of higher performance in the upcoming motor buy.
5.
New ACS Systems
The SRWG supports
NSROC's three year plan to transition
attitude control system (ACS) operations into a consolidated guidance
and
navigation control (GNC) group. This
plan should lead to lower support and refurbishment costs for all ACS's
while
improving performance. We especially
encourage all efforts leading to expedient development and routine use
of the
ST-5000 startracker to replace the aging Ball startracker.
Successful development of the ST-5000 has
great market potential beyond the sounding rocket program, the
exploitation of
which would be especially beneficial to NSROC (and hence presumably to
the
sounding rocket program) given the current fiscal environment.
6.
Success Criteria
Success
criteria are
used by NASA, according to the Sounding Rocket Program Handbook, "to provide
objective criteria that will be used to determine the success or
failure of the
mission after all operations are completed." Two
levels of success are defined. A
"comprehensive" success results
in all or nearly all of the mission objectives being achieved. A "minimum" success occurs when
performance is degraded to the extent that some or all of the mission
objectives are significantly compromised, although the return of
scientific
results is still likely. The formulation
of these criteria is driven by the Principal Investigator, but
negotiations
with Wallops often result in minor modifications. These
criteria are then "flowed
down" to prescribe the design of the mission.
With the advent of
the NSROC
contract and its emphasis on performance-based fees, success criteria
are now
used not only to measure the degree of success of a mission, but also
are a
determinant of award fees. This new use
of the success criteria has had some negative effects.
For example, it is in the interest of the
NSROC contractor to negotiate success criteria such that both cost and
risk are
minimized. Although the award fee
structure
is based on complexity and therefore has some basis in the assumed
risk, it
seems that there nevertheless is an impetus for the NSROC contractor to
attempt
to negotiate less challenging success criteria. Science
goals may be compromised as a result. As
an illustration, a requirement for
pointing knowledge of one degree has become problematic under NSROC. The gyroscope subsystem successfully used in
the past for such purposes has a stated accuracy of three degrees. The employment of rigid body mechanics in the
post-flight analysis has routinely allowed one-degree attitude
solutions. However, the NSROC contractor
has been
unwilling to accept this scenario and has insisted on either using a
more
accurate but more costly hardware solution or that the success criteria
be
relaxed. Here it is seen that the use of
success criteria as a determinant for award fee can affect the total
science
return adversely.
There are other
indications that
the concept of success criteria may need to be modified.
In some cases, a successful experiment
requires multiple, nearly simultaneous launches to be successful. However, success criteria are attached to
each flight. Success criteria requiring
performance of more than one mission have not been allowed. In this paradigm, an experiment could fail
despite each of the constituent missions meeting their individual
success
criteria. Another weakness in the
current system is that experimenters have sometimes been required to
revise
success criteria regarding based on small changes in the performance
predicted
by refined NSROC estimates. The SRWG
urges that the Sounding Rocket Program office ensures that success
criteria not
be watered down for the purpose of increasing fees for NSROC.
7.
Feedback to PI's on Costs Dialog
The SRWG is confused
about who has responsibility for
the cost of an individual mission (the P.I.? Wallops? NSROC? HQ?),
particularly with respect to detailed
decisions regarding hardware items, overtime, field work, etc. We request that this situation be
clarified. In particular, there is a
fundamental problem with cost feedback. It
is in the PI's interest to request more things
for any given mission,
and it is in NSROC's interest to add them to the mission, and to bill
NASA
accordingly. In the past, the constraint
has always been the Program Office at Wallops. In
the current situation, this oversight appears
particularly difficult
for the markedly understaffed program office. Such
discussions concerning cost feedback could take
place at the RDM,
although the P.I. is not invited to discuss detailed costs and contract
terms
with NSROC.
8.
Bookkeeping of Viper Darts (Lynch &
Pfaff)
The SRWG does not
believe that Viper Darts should be
counted as separate launches (on par with larger rockets) from the
standpoint
of rating the overall performance of the program on a yearly basis. Recognizing that sophisticated
miniaturization of Viper Dart payloads require in many places advanced
engineering, it still does not seem right to count Viper Darts
alongside the
larger rockets. This skews the
statistics and falsely portrays the program launch activity as more
robust than
it actually is. We suggest that all
Viper Darts in a given set be counted as one launch, or that some other
criteria or category be used.
NASA Sounding Rocket
Working
Group
Dr.
Robert F. Pfaff, Jr. (Chair)
NASA/Goddard
Space Flight Center
Dr.
James Clemmons
Aerospace
Corporation
Dr.
Joseph Davila
NASA/Goddard
Space Flight Center
Dr.
Greg Delory
University of California at Berkeley
Dr.
Kristina Lynch
University of New Hampshire
Dr.
Stephan McCandliss
Johns Hopkins University
Dr.
Scott Porter
NASA/Goddard
Space Flight Center
Dr.
David Slater
Southwest
Research Institute
Dr.
James Ulwick
Utah State University
Dr.
Erik Wilkinson
University of Colorado
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