I.
High Altitude Sounding Rocket
The Sounding
Rocket Working Group (SRWG) strongly supports the concept and
implementation of
a High Altitude Sounding Rocket (HASR) and urges the Wallops Flight
Facility to
continue all efforts to make this project a reality.
We believe the HASR should be the highest
priority new technology development for the program.
When implemented,
the HASR will profoundly advance future rocket-based investigations
across all
scientific disciplines, including X-ray and UV astronomy, planetary
science,
space physics, and micro-gravity. Furthermore,
this new vehicle presents a unique and
inexpensive
engineering test bed for high velocity landing and aerobraking systems,
such as
currently being considered for probes that will impact on other planets
and
return samples to the earth.
The preliminary
performance requirements for an HASR are that it achieve an altitude of
3000
km, provide ~2400 seconds of observing time above 100 km, and include
the
option to be recoverable. In addition,
the preliminary HASR configurations presented thus far have 38”
(~1meter)
diameter experiment sections, significantly larger than current payload
diameters (17” and 22”). As typical
astronomy/planetary/solar BBIX payloads currently achieve approximately
240
seconds of actual observing time above the atmosphere, the HASR would
provide
an order of magnitude more observing time. Since
the larger diameter rocket payload would
provide an additional 3
to 6 times more geometric collecting area, the combination of these
factors
would provide 10 to 60 times more sensitivity for telescope instruments
than is
typically afforded with the current rocket technology.
In addition to
payloads that seek primarily to increase observing time above the
atmosphere, a
high altitude sounding rocket would also be very advantageous to Space
Physics
investigations of Geospace. For example,
such a high altitude rocket would penetrate the prime auroral and cusp
acceleration regions (> 2500 km) where they would gather high
resolution
particle and fields measurements at a very slow velocity compared to
orbiting
satellites. The payload would be able to
stay within the region of interest on time scales that would permit
longer
period phenomena, e.g., pulsations, to be resolved, which is not
possible with
in-situ probes on low earth orbiting satellites, such as FAST, that
traverse
such regions in a few minutes. In
addition to auroral studies, such missions would also provide new
investigations of the inner radiation belts and other space physics
phenomena. The larger diameter payload
would permit more extensive sub-payloads to be developed for
multi-point
sampling of a variety of regions of geophysical interest.
In the realm of
engineering, the new vehicle promises to be highly beneficial for the
testing
of new scientific instrumentation, such as that proposed for orbiting
satellites at low perigee, as well as the testing of smart landers and
aerobraking systems. The ability to test
planetary re-entry engineering devices opens a new area for research
within
NASA’s sounding rocket program.
The SRWG notes
that the HASR promises to be highly cost effective.
For example, a typical BBIX astronomy
sounding rocket mission costs approximately $1.5M and provides
approximately 6
minutes of observing time. In contrast,
the HASR system is projected to cost $5M but would provide 40 minutes
of
observations. Thus, in addition to the
new experiments that are afforded by such a longer duration, high
altitude
platform, the combined increase in observing time with the relatively
low cost
vehicle would decrease the cost of observations per minute by a factor
of two.
Finally, the SRWG
emphasizes that throughout the history of scientific exploration, major
breakthroughs have traditionally occurred whenever instrument
performance
metrics have significantly increased. The
development of the HASR represents just such an
opportunity for NASA
and the scientific community. The SRWG
believes that the HASR is the next logical step for NASA’s Sounding
Rocket
Program to take, not only for the immediate advances that it will
achieve in
scientific research, but also for the development of the next
generation of
instruments for future satellite missions.
II.
New Mesosphere Rocket
The scientific
community has
long recognized the importance of exploring the earth’s upper
atmosphere
between 50 and 120 km. Sounding rockets
present the only means to gather in situ sampling of the many
phenomena
and critical processes in this region including momentum coupling,
chemistry,
and vertical transport.
<>The
current
inventory of NASA sounding rockets are not optimum for exploring the 50
to 120
km region. The single stage Orion
vehicle barely reaches 90 km and the more complex two-stage Nike-Orion
typically take payloads above this region. Although
it is straightforward to include ballast on
such higher
performing vehicles, these larger diameter payloads tend to be somewhat
bulky
and ultimately, for certain experiments, may interfere in a detrimental
way
with the atmospheric medium that is being measured.
Further, even though such rockets utilize
surplus vehicles, their utilization is still too expensive for repeated
(5-10)
launches in a given experiment. The
result is that missions based on simple (i.e., very small) payloads and
repeated launches are impractical given the current inventory of NASA
sounding
rockets.
In the past, the low
cost Super-Arcas vehicle was available for sampling
this region but we understand that this supply of motors at Wallops has
been
exhausted. Efforts were made over the
last 10 years to utilize the Loki and Viper motors with 2 inch
“dart-like”
payloads to study the lower part of this region. This
effort has been largely unsuccessful due
to the difficulty of working with the small diameter Dart payload and
the
vagaries of the Viper motor performance.
The SRWG strongly
recommends that Wallops develop a low-cost sounding
rocket system for studying the 50 to 120 km region.
Experience with the small 2 inch Viper Dart
systems has shown that a larger (e.g., 4 to 6 inch) system may be
better suited
for science payloads and should reduce developmental costs of
instruments and
sub-systems. In addition to telemetry
and GPS positioning systems, some of the features that we recommend be
included
in the new mesospheric payloads are the following:
The payload must be able to accommodate the
deployment of booms through doors or by shedding skin sections. It is highly desirable to have a very
portable launch system for these rockets with low dispersion so that it
might
be easier to take them to non-standard launch locations.
Above all, the cost of preparing and
launching such a vehicle must be small (e.g., significantly lower than
that of
the Orion vehicle) so that scientific investigations composed of
numerous
flights are practical within one launch campaign.
III.
Apparent NASA/DoD Resource Conflict
The SRWG recognizes
the importance and financial benefit of the new work
that NSROC has brought to the program involving Department of Defense
(DoD)
projects. To the extent that this work
improves the capability of the program and lowers the price tag to NASA
of a
given sounding rocket project, the SRWG congratulates NSROC. Our chief concern, however, is that such
outside projects threaten to detract from the core NASA Code S-funded
science
projects. For example, we have already
heard from NASA-funded experimenters that their mission development was
held up
while various NSROC team members were completing DoD projects. Although this may be true for a limited time
for any given project, the SRWG is concerned that, in general, a
“paying”
external customer such as DoD could have priority compared to a NASA
project
that might be viewed as “in house” and hence capable of waiting.
Further,
as stated in our findings from the last meeting, the SRWG is concerned
that
NSROC may focus on developing technology and support systems that
enhances
their ability to acquire non-NASA new business at the expense of the
NASA
science community needs. We would like
to better understand how NSROC delineates, if at all, between R and D
efforts
for NASA projects and those, for example, for DoD.
Again, we seek to understand whether there
are separate resources for developing technologies for NASA compared to
outside
projects, and how the resources to develop technology for each effort
are
accounted for.
In
summary, the SRWG acknowledges the benefit of NSROC bringing in outside
work. We seek assurances that these
additional projects will not be to the detriment of the NASA sounding
rocket
missions.
IV.
Technology Roadmap
The
SRWG applauds the Technology Roadmap developed by the Sounding Rocket
Program
Office. This constitutes an excellent
formulation for the initiation and tracking of new technology within
the
Sounding Rocket Program. The SRWG fully
endorses this initiative and believes that the SRPO is uniquely suited
to both
create and maintain this roadmap, matching both immediate needs and
future
possibilities with limited program resources. For
our part, the SRWG seeks to provide inputs to
the roadmap,
particularly with respect to those new technologies that will provide
the
greatest scientific impact. We look
forward to working with the SRPO on this new aspect of the program.
Although
the new technology roadmap is off to a good start, it is not clear to
the SRWG
how various items on the roadmap are connected to science priorities
and how
the timeline for the achievement of several new technologies is
established. We therefore, seek
clarification of how the SRPO envisions the roadmap to develop over
time. We also remain uncertain how
resources for
new technology are apportioned from NASA funds, and how NSROC
determines which
new technology to pursue using its R and D funds.
V.
Coarse Gyro Attitude
Determination
The
SRWG is pleased that NSROC is dedicating resources to improving coarse
attitude
knowledge and its verification, as evidenced by recent presentations by
NSROC.
The SRWG
encourages NSROC to continue to poll the user community concerning
required
features of coarse attitude information and its application and to
provide to
investigators attitude data that has been verified to ensure its
accuracy. This is particularly essential
for new users
who might use the attitude data without an independent means to check
them
before inclusion in the scientific analysis.
The SRWG notes
that the documentation for using the coarse attitude data is
essentially
non-existent, and urges NSROC to prepare a brief document that outlines
the
procedures to use the Wallops coarse attitude data as well as the steps
it
takes to verify the data. The user
community, represented by the SRWG, would be very willing to form a
sub-committee or splinter group to work with Wallops to develop such a
User
Guide. We believe that such a guide is
particularly important as NSROC prepares to implement new coarse
attitude
systems for routine measurements on future flights.
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. Walt Harris
University of
Wisconsin
Dr. James LaBelle
Dartmouth College
Dr. Kristina Lynch
University of New
Hampshire
Dr. Stephan McCandliss
Johns Hopkins
University
Dr. Scott Porter
NASA/Goddard Space
Flight Center
Dr. Charles Swenson
Utah State University
Dr. Erik Wilkinson
University of Colorado
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