Space Communications: Performance of NASA's White Sands Ground Terminal

Published by the Government Accountability Office on 1990-05-29.

Below is a raw (and likely hideous) rendition of the original report. (PDF)

      ‘P                                                                  -.
F?,            United   States   General   Accounting        Office
               Report to the Chairman, Committee on
GAO            ‘Science,Space, and Technology, House
                of Representatives

               Performances of
               NASA’s White Smds
               Ground Terminal
                   United States
GAO                General Accounting  Office
                   Washington, D.C. 20548

                   Information    Management      and
                   Technology    Division


                   May 29,199O

                   The Honorable Robert A. Roe
                   Chairman, Committee on Science,
                     Space, and Technology
                   House of Representatives

                   Dear Mr. Chairman:

                   This report responds to your request for information about the perfor-
                   mance and reliability of the National Aeronautics and Space Administra-
                   tion’s (NASA) White Sands ground terminal in White Sands, New Mexico.
                   The White Sands terminal is the main ground component of NASA’s
                   Tracking and Data Relay Satellite System (TDRSS), which also includes
                   three space-based satellites and the network control center at the God-
                   dard Space Flight Center in Greenbelt, Maryland.

                   Various satellites and the space shuttle use TDRSSto relay tracking and
                   scientific data to users. This relay through the White Sands terminal is
                   essential to the safety of NASA astronauts and the receipt of scientific
                   data from space experiments. In our April 1989 report’ to you on NASA’s
                   communications support for earth orbiting spacecraft, we noted
                   problems with the reliability of the automated equipment and software
                   at the White Sands terminal. As agreed by your office, our current
                   objective was to determine how ~ti evaluates and assesses the per-
                   formance and reliability of this terminal. Details on our objective, scope,
                   and methodology are in appendix I.

                   NASA does not evaluate the reliability of the White Sands terminal.
Results in Brief   Instead, it assesses performance in terms of how the terminal met the
                   user’s data transmission needs, which it calls user support proficiency.
                   Given this criterion, NASA has exceeded its goal of 95 percent user sup-
                   port proficiency since 1986 and is, on average, delivering telecommuni-
                   cations services to users about 99 percent of the time when scheduled to
                   do so. Moreover, TDRSSusers expressed general satisfaction about the
                   services they received.

                   NASA’S user support proficiency      measure does not address the terminal’s
                   reliability   or availability, which are standard engineering measures of

                    ‘SpaceOperations:NASA’sCkxnnunicatiom Supportfor Earth Orbiting Spacecraft(GAO/
                    lhT?‘EC_89_41, Apr. 7,1989)

                    Page 1

TDRSS Usage Is Increasing   Although TDRSScapacity exceeds present use, NASA anticipates demand
                            for services will significantly increase in the 1990s. Since TDRSSbegan
                            initial operations in 1983, NASA has provided services to various space-
                            craft including the space shuttle, the Solar Mesosphere Explorer, the
                            Earth Radiation Budget Satellite, Solar Maximum Mission, and LAND-
                            SAT 4 and 5. In addition, a new generation of spacecraft are now using
                            TDRSS, including the Hubble Space Telescope and the Cosmic Background
                            Explorer. NASA statistics indicate that since 1983, actual use of TDRSS'
                            high data rate telecommunications services reached a high of about 13
                            percent of capacity in mid-1989 and is projected to increase to about 42
                            percent of capacity in 1993.

                            According to NASA officials, the maximum operating capacity for high
                            data rate services is estimated at 70 to 75 percent of total time available.
                            Operating continuously above this level would result in a rapid decline
                            in service. Under normal circumstances, about 25 to 30 percent is
                            required for handling peak work loads, as well as for factors such as
                            establishing communications visibility-the    time needed to line up a
                            user satellite with a TDRSSsatellite so communications can be relayed to
                            the ground terminal.

Terminal Problems Are       The White Sands terminal is contractor owned and operated at a cost of
Being Addressed             about $25 million annually, according to a NASA budget manager. The
                            terminal has two principal functions: (1) to safely operate and maintain
                            the three TDRSSrelay satellites, and (2) to provide uninterrupted commu-
                            nication between earth orbiting spacecraft and their users. The terminal
                            was designed to support spacecraft users from 1983 through 1993.
                            Between 1983 and 1985, NASA recognized various problems with TDRSS,
                            including the terminal, and began a comprehensive study to identify
                            problems needing resolution.

                            Having identified problems in system design, tracking, operations, and
                            testing, NASA sponsored a 5-year terminal enhancement project, costing
                            about $34 million, scheduled to be completed in July 1990. The project
                            seeks to improve the reliability, maintainability, and availability of the
                            terminal through the end of its operational life in 1993. For example,
                            NASA upgraded, added, and replaced various equipment components of
                            its testing, automated data processing, radio frequency, command, and
                            monitoring systems to reduce failure rates and to improve reliability and

                            Page 3                               GAO/IMTECsoSG Ground Terminal Perfo-ce

User satisfaction is another indicator of terminal performance. Users
submit their original requests for telecommunications services to the
network control center at Goddard at least 3 weeks before the services
are needed. The control center aggregates these requests and during the
ensuing 3 weeks negotiates a final telecommunications schedule with all
spacecraft users based on priority ranking, planned hardware and
software upgrades, and maintenance schedules. Although the control
center sets and maintains user schedules, the contractor who operates
the terminal is responsible for keeping the equipment functioning to
support the user schedules.

Users we interviewed were generally satisfied with the telecommunica-
tions services they had received. For example, a representative from the
shuttle program, a high priority user, said he was satisfied with the ser-
vices provided, and added that shuttle data transmissions can only be
preempted by an emergency on board another spacecraft. Should this
occur, scientific experiments can generally still be performed because
the data from these experiments are recorded on tape. Should transmis-
sions be interrupted, spacecraft tape recorders can be rewound and the
data retransmitted at a later time. The shuttle representative was confi-
dent that the terminal will be able to provide adequate service to meet
the shuttle’s needs until 1993, when the terminal is scheduled to be

LANDSAT users were also generally satisfied with the services received.
LANDSAT sells earth images to the private sector, with about 20 percent
of the images ordered in advance. LANDSAT users pointed out, how-
ever, that LANDSAT spacecraft lacked on-board tape recorders. As
such, interruptions in telecommunications resulted in lost images. For
example, during the first 5 months of 1989, LANDSAT spacecraft lost
502 minutes of data, representing about 20 percent of the total TDRSS
da&a losses for the period. LANDSAT representatives told us they could
not readily determine the financial impact of this loss.

Some users had concerns about the administrative process of using
TDRSS.Several mentioned having to negotiate changes in their initial
schedule request with NASA due to conflicts with other users or other
NASA activities. Despite the additional work and frustrations, users said
they generally received adequate transmission time to accomplish their
mission objectives. Even when NASA changed a schedule just before
transmission time, or when transmissions were interrupted, they said
mission impact was usually minimal.

Page 6                             GAO/EWlXG99-66Ground Terminal Performance

                      Contractor officials said they cannot measure the mean time between
                      equipment failures, or system reliability, because the terminal’s elec-
                      tronic system lacks the comprehensive diagnostic capability necessary
                      to precisely capture real-time data on all equipment failures. As a result,
                      in some cases maintenance personnel become aware of an equipment
                      failure only if it is being used to transmit data at the time of failure. In
                      other words, a component failure in a spare chain of equipment or any
                      unused equipment could go unnoticed until put to use.

                      In 1988 NASAawarded a contract for the design and development of a
                      new terminal at White Sands by 1993. The terminal manager told us
                      that in contrast to the old one, NASA will own the new terminal and
                      therefore, has developed specifications emphasizing its reliability, avail-
                      ability, and maintainability. These specifications address reliability
                      requirements and call for (1) developing a fault isolation system to iden-
                      tify equipment subcomponent failures, and (2) measuring mean time
                      between failures to determine the terminal’s reliability.

System Availability   System availability, another performance indicator focusing on equip-
                      ment, measures the mean time between component failure and mean
                      time to repair. Availability is computed by dividing the time the system
                      was actually available for use by time it should have been available had
                      it functioned according to specifications.

                      Although N&4 officials said they routinely gathered information on the
                      availability of some terminal equipment, they could not supply detailed
                      data on when it was unavailable. The contractor staff said that they
                      were enhancing the maintenance program during the remaining contract
                      period by developing a management information system to supply this
                      data. Because NASA could not provide comprehensive data on equipment
                      availability or summary information on total system downtime, we
                      could not assess the terminal’s overall availability.

                      As in the case of reliability, NASA’S contract specifications for the new
                      terminal require that (1) the system be available 99.9 percent of the
                      time, and (2) actual availability be measured against this performance

                      The current performance of the White Sands terminal-using      NASA’S
Conclusion            measurement of support proficiency-is     high. However, because the ter-
                      minal is only processing a small percentage of the estimated future

                      Page 7                               GAO/JMTEG96-56Ground Terminal Performance
Page 9   GAO/lMTEG96-66 Ground Terminal Performance
Appendix II

Major Contributors to This Report

                       Stephen A. Schwartz, Assistant Director
Information            Ronald W. Beers, Assistant Director
Management and         Leonard J. Latham, Technical Adviser
Technology Division,   Janice D. Troupe, Evaluator

Washington, D.C.

                       Ronald J. Guthrie, Regional Management Representative
Denver Regional        Anthony R. PadiIla, Evaluator-in-Charge
Office                 Elizabeth Donnelly, Evaluator

(610496)               Page 11                           GAO/JldTEC96.66 Ground Terminal Perfo-m
Appendix I

Objective, Scope,and Methodology

               In June 1989, the House Committee on Science, Space, and Technology
               asked for information on how NASA evaluates and assesses the perfor-
               mance and reliability of its White Sands ground terminal. To evaluate
               the terminal’s performance, we reviewed three indicators of a system’s
               performance: NASA’S user support proficiency, which measures how well
               the terminal is meeting user schedules for telecommunications services;
               user satisfaction; and equipment reliability and availability. We
               obtained monthly statistics on user support proficiency from NASA and
               CONTEL, Inc., the contractor. We then compared these performance
               data to the 95-percent support proficiency requirement established in
               NASA’S performance evaluation plan with CONTEL. We also interviewed
               NASA officials at the Goddard Space Flight Center in Greenbelt, Mary-
               land, and the White Sands Ground Terminal in White Sands, New Mex-
               ico, to determine how they collect, analyze, and report data on user
               support proficiency. We did not independently test the accuracy of this

               We also interviewed the principal users of TDRSSon their degree of satis-
               faction with the terminal’s performance. These included project staff
               from the program offices of Space Shuttle, Solar Mesosphere Explorer,
               Earth Radiation Budget Satellite, Solar Maximum Mission, and LAND-
               SAT 4 and 5.

               We also determined the extent to which NASA and CONTEL use standard
               engineering measurements of equipment reliability and availability to
               evaluate the performance of the ground terminal system. We reviewed
               contract documents to verify whether NASA had required the contractor
               to perform such measurements and if NASA had also established reliabil-
               ity and availability performance criteria. We also interviewed NASA and
               contractor officials at the terminal to find out if the system was
               designed with the diagnostic capability necessary to precisely capture
               reliability and availability data and, if so, what data were collected.

               We obtained comments on this report from officials at NASA headquar-
               ters, the Goddard Space Flight Center, and White Sands terminal. Their
               comments have been incorporated into the report where appropriate.
               We performed our work from June 1989 to March 1990 in accordance
               with generally accepted government auditing standards.

               Page 10                            GAO/lMTEGW-50 Ground Terminal Performance
work load, it is not being stressed. In the absence of comprehensive reli-
ability and availability data which is important for assessing system
performance under increasing work loads, NASA officials cannot accu-
rately predict how well or how long the terminal will perform in the

Responsible officials from NASA provided comments on this report. These
comments are included where appropriate. As arranged with your
office, unless you publicly announce the contents of this report earlier,
we plan no further distribution until 30 days from the date of this letter.
We will then provide copies to appropriate congressional committees,
the Administrator of NASA, and other interested parties upon request.

This work was performed under the direction of Samuel W. Bowlin,
Director for Defense and Security Information Systems, who can be
reached at (202) 275-4649. Other major contributors are listed in appen-
dix II.

Sincerely yours,

Ralph V. Carlone
Assistant Comptroller General

Page g                              GAO/lMTEG90-66 Ground Terminal Performance

                         Two users wondered whether TDRSScould meet higher future demand
                         for services. Similar concerns were expressed in a December 1989 NASA
                         report2 that said

                         the practical problems of scheduling and conducting an operation with TDRSS are
                         substantial, even considering the recent redesigns within the network control
                         center. In other words, the current design and implementation for scheduling and
                         operationally utilizing TDRSS is fragile. There is considerable uneasiness that the
                         TDRSS, when confronted by increasing high priority loading, is likely to become
                         grossly inefficient and that low priority users will therefore be left without support.

                         Besides user support proficiency and satisfaction, determining a sys-
System Reliability and   tern’s reliability and availability are important. These measures are
Availability Are         standard engineering crncepts for assessing a terminal’s current per-
Uncertain                formance and predicting its future performance. However, NASA and
                         contractor officials at White Sands do not measure system reliability,
                         nor do they maintain sufficient data to determine the total time the sys-
                         tem equipment was unavailable for use. As a result, NASA cannot predict
                         how reliably the terminal will perform in the future.

System Reliability       Reliability, a standard engineering indicator of a system’s technical per-
                         formance, measures the actual mean time between component failures
                         and, when compiled over a number of years, can be used to predict the
                         likelihood of system failures under future operating conditions. Thus,
                         data on the failure rates of the terminal equipment could be used to
                         model and predict how reliably it will perform in the 1990s when usage
                         is expected to grow significantly.

                         But according to NASA’S ground terminal manager, the 1976 contract for
                         the design and development of TDRSSdid not require the contractor to
                         develop built-in diagnostic capability to monitor the technical reliability
                         of the terminal’s equipment. Although such diagnostic capability was
                         available at the time of contract award, NASA wanted to buy telecommu-
                         nications services, not equipment. Hence, NASA’S contract and perform-
                         ance criteria focused on the ultimate delivery of telecommunications
                         services to users, not on equipment reliability. NASA saw the operation,
                         maintenance, performance, and reliability of the equipment as the
                         responsibility of its owner, the contractor.

                         21nfornmtionSystemScenariosfor SpaceScienceand Applications, Section2.42 Data RelaySat&
                         lites and GroundStations SystemDiversity and Dependability,December1989

                         Page 6                                    GAO/IMTEGW-66 Ground Terminal Performance

                                     NASA plans to replace the White Sands terminal in 1993. NASA then plans
                                     to completely upgrade the old terminal, making it identical to the new
                                     one, in order to provide additional capacity and backup capability to
                                     support TDFSS demand in the 1990s. Given an overall investment of
                                     about $427 million for building the new terminal and upgrading the old
                                     one, NASA plans no major interim upgrades of the old terminal. However,
                                     NASA officials said they would continue to make minor enhancements
                                     until shortly before the new one becomes operational.

                                     Statistics from 1986 to 1989, confirmed by discussions with TDRSSusers,
Terminal Is Generally                indicate the terminal exceeds NASA'S performance expectations. NASA
Meeting User Needs                   officials told us their primary indicator of overall terminal performance
                                     was user support proficiency-a      measure which compares the actual
                                     amount of communications relay time provided to users with the
                                     amount of time scheduled for them. As shown in the figure below, NASA'S
                                     annual support proficiency statistics from 1986 to 1989 show that the
                                     terminal exceeded NASA'S goal of 95 percent user support proficiency
                                     and was, on average, providing communications services to users about
                                     99 percent of the time when scheduled to do so.

Figure 1: User Support Proficiency
                                     190   Percentage   of proficiency

                                                                         1997                     1998

                                     page4                                      GA0/IMTFS9068Ground      TermhalPetfonnance

             equipment failure rates and repair times, and of the total time the equip-
             ment is available for use so that predictions can be made about future
             performance. NASA cannot use these measures because the terminal lacks
             the necessary diagnostic capability to capture information on the inci-
             dence and duration of equipment failures.

             Use of the White Sands terminal is expected to increase significantly
             during the next several years. In June 1989, demand for high data rate
             telecommunications services-one of several types provided to users-
             was about 13 percent of available TDRSS capacity. However, demand is
             projected to increase to about 42 percent in 1993. Without reliability
             and availability data, NASA officials cannot predict how well the terminal
             will perform or how long it will be available for use in the future.

             NASA  plans to replace the White Sands terminal in 1993. Recognizing that
             increased demand for services in the 1990s will require greater assur-
             ance that the new terminal be reliable and available, NASA’S design and
             development contract for the new terminal requires a diagnostic capabil-
             ity as well as specifications for the standard measurements of reliability
             and availability to determine system performance. NASA also plans to
             upgrade the old terminal after the new one becomes operational. The
             estimated cost of these projects is $427 million.

             In 1983, NASA launched and began operating its first TDRSS satellite. TDRSS
Background   became fully operational in June 1989 with its set of two active satel-
             lites and one spare. The active satellites are located over the Atlantic
             Ocean, off the coast of Brazil; and over the Pacific Ocean, southwest of
             the Hawaiian Islands. The spare is located between the two and can be
             used if a major problem occurs with one of the active satellites. TDRSS
             allows an earth orbiting spacecraft, like the space shuttle, to relay its
             communications through the active TDRSS satellites to the White Sands
             terminal and on to its users.

             The types of communications relayed through TDFSS include (1) data
             from spacecraft on their orbital positions, (2) scientific information col-
             lected by on-board instruments, (3) commands from users to operate the
             spacecraft, and (4) engineering data on the health and safety of user
             spacecraft. Communications through TDRSS are available 24 hours a day,
             7 days a week.

             Page 2                              GAOlIMTEC9O-56 Ground Terminal PerPormance