Findings & Concerns

Meeting of January 13, 2003
Sounding Rocket Working Group
National Aeronautics and Space Administration



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