Findings & Concerns

Meeting of June 9, 2000
Sounding Rocket Working Group
National Aeronautics and Space Administration

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
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
State University

Dr. Erik Wilkinson
University of Colorado