Space Shuttle: Declining Budget and Tight Schedule Could Jeopardize Space
Station Support (Letter Report, 07/28/95, GAO/NSIAD-95-171).
Pursuant to a congressional request, GAO examined the extent to which
the space shuttle program can support the space station's assembly
requirements, focusing on the: (1) impacts of the declining shuttle
budget; and (2) demanding schedule to support the space station.
GAO found that: (1) the National Aeronautics and Space Administration's
(NASA) plans for increasing the shuttle's lift capability are complex
and involve about 30 individual actions such as hardware redesigns,
improved flight design techniques, and new operational procedures; (2)
some of the hardware redesign programs have experienced early
development problems, and the potential exists for additional problems;
(3) NASA schedule for meeting the space station's launch requirements
appears questionable in the declining budget environment; (4) NASA must
successfully complete numerous shuttle-related development programs on a
tight schedule to support the first space station launch; (5) the
remaining launch schedule is compressed and will be difficult to achieve
without additional funding or more efficient processing methods; (6)
delays in the launch schedule could substantially increase the station's
cost; (7) NASA plans to forgo some of the shuttle's recertification
activities and full integration testing of the propulsion system until
the first launch of station components; (8) NASA plans to assess the
implications of the design changes through a combination of tanking and
component tests and systems analyses; and (9) NASA must ensure that the
implications of integrating numerous individual design changes are fully
understood and safety is not compromised.
--------------------------- Indexing Terms -----------------------------
REPORTNUM: NSIAD-95-171
TITLE: Space Shuttle: Declining Budget and Tight Schedule Could
Jeopardize Space Station Support
DATE: 07/28/95
SUBJECT: Space exploration
Systems analysis
Aerospace research
Cost analysis
Mission budgeting
Future budget projections
Aerospace engineering
Transportation safety
Systems design
IDENTIFIER: NASA Space Station Program
NASA Space Shuttle Program
NASA International Space Station Alpha Program
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Cover
================================================================ COVER
Report to the Chairman, Subcommittee on Oversight of Government
Management and the District of Columbia, Committee on Governmental
Affairs, U.S. Senate
July 1995
SPACE SHUTTLE - DECLINING BUDGET
AND TIGHT SCHEDULE COULD
JEOPARDIZE SPACE STATION SUPPORT
GAO/NSIAD-95-171
Space Shuttle
Abbreviations
=============================================================== ABBREV
NASA - National Aeronautics and Space Administration
GAO - General Accounting Office
Letter
=============================================================== LETTER
B-260359
July 28, 1995
The Honorable William S. Cohen
Chairman, Subcommittee on Oversight
of Government Management and the
District of Columbia,
Committee on Governmental Affairs
United States Senate
Dear Mr. Chairman:
The National Aeronautics and Space Administration (NASA) plans to use
the space shuttle on 21 flights over a 5-year period to assemble the
International Space Station. To meet this requirement, the shuttle
will have to undergo substantial redesign to gain additional lift
capability. As requested, we examined the extent to which the
shuttle program can support the space station's assembly
requirements. In doing so, we focused on the impacts of a declining
shuttle budget and a demanding schedule to support the space station.
BACKGROUND
------------------------------------------------------------ Letter :1
The shuttle is the only U.S. launch vehicle capable of carrying
humans into space. As a result, it will be critical to the space
station's assembly and operation. From December 1997 to June 2002,
NASA plans to use the shuttle primarily to transport station
components into orbit for assembly. During this period, 27 of the
shuttle's 34 primary payloads are to be station-related.\1
At times, only two of the four shuttles will be available for station
assembly. One shuttle--Columbia--cannot provide adequate lift, and,
one of the remaining three shuttles will be undergoing scheduled
maintenance during some portions of the assembly schedule. Also,
most station components will have to be launched in a particular
sequence to provide power and structural support for other hardware.
In March 1993, the President directed NASA to redesign the space
station. The new configuration--renamed the International Space
Station--combines the efforts of Europe, Japan, Canada, Russia, and
the United States. It also increased the station's planned orbital
inclination to make it more accessible from Russian launch sites,
creating the need for additional shuttle lift capacity. Easterly
shuttle launches from Kennedy Space Center take advantage of the
earth's normal west to east rotation. Launches to higher
inclinations such as those needed for the space station lose some of
this advantage, with a resulting loss in lift capability.
In November 1993, the space station program manager requested that
the space shuttle program implement modifications to provide the
increased lift needed to support space station assembly. The shuttle
program office responded by committing the program to increasing lift
capability by at least 13,000 pounds on every station flight.
--------------------
\1 NASA plans to use the shuttle for 21 space station assembly
flights and 6 additional station-related missions.
RESULTS IN BRIEF
------------------------------------------------------------ Letter :2
NASA's plans for increasing the shuttle's lift capability are complex
and challenging, involving about 30 individual actions, including
hardware redesigns, improved navigational or flight design
techniques, and new operational procedures. Some of the hardware
redesign programs have experienced early development problems, and
the potential exists for additional problems according to one
independent review team.
NASA's schedule for meeting the space station's launch requirements
appears questionable--particularly in a declining budget environment.
To support the first space station launch, NASA must successfully
complete numerous shuttle-related development programs on a tight
schedule. The remaining launch schedule is compressed and will be
difficult to achieve without additional funding or more efficient
processing methods. Delays in the launch schedule could
substantially increase the station's cost.
The shuttle's modification and launch enhancement program includes
plans to defer some recertification activities and forgo full
integration testing of the propulsion system. As a result, shuttle
modifications will be fully integrated and flown for the first time
on the first launch of station components. NASA plans to assess the
implications of the design changes through a combination of tanking
and component tests and systems analyses. Given the magnitude and
complexity of the shuttle enhancement program, we believe it is
prudent to take additional measures to ensure that (1) the
implications of integrating numerous individual design changes are
fully understood and (2) safety is not compromised.
NASA'S PROGRAM TO PROVIDE ADDED
LIFT IS COMPLEX AND CHALLENGING
------------------------------------------------------------ Letter :3
The lift enhancement plan--first approved in March 1994--has been
amended a number of times to introduce new ideas for achieving the
required lift at the least cost. The original plan identified 13,000
pounds of added lift at a cost of about $535 million. In May 1995,
NASA estimated that about 16,100 pounds of lift gain would be
achieved at a cost of about $444 million. Both estimates included
some recurring costs for enhancement hardware, as well as costs to
integrate the enhancements, and reserves to cover the possible need
for additional changes.
The current plan includes about 30 individual actions that involve
hardware redesign, improved navigational or flight design techniques,
and new operational procedures.\2 Figure 1 depicts the percentage of
added lift NASA estimates will come from these areas, based on the
May 4, 1995, approved baseline.
Figure 1: Actions to Increase
Shuttle Lift Capability
(See figure in printed
edition.)
Hardware design changes account for more than one-half of the added
lift. The primary redesign program is the development of a new
external fuel tank--the super lightweight tank--which involves
incorporating a new aluminum alloy into the tank design. This alloy
will reduce the tank's weight and change its material properties. In
addition, the tank will have to accommodate a new set of design
loads\3 created by the mix of hardware and flight design changes.
Other development programs necessary to support the space station
include various orbiter\4 modifications and improved main engines.\5
The super lightweight tank program has experienced some early
development problems that could affect its performance. Shortly
after beginning development of this tank, technical concerns about
the properties of the new material were raised. An independent
review of the program was performed, and based on its results, NASA
adopted a more rigorous test plan for the tank and modified the
tank's production strategy. More recently, the uniqueness of the new
metal caused delays in manufacturing a test article. NASA believes
these early concerns have been resolved, but it recognizes that
uncertainty with the development and manufacturing of the new
material could ultimately reduce the amount of lift gain projected
for the new tank.
The main engine improvements are expected to make the engines heavier
than the current engines. However, the new engines are expected to
be more efficient, thus needing less propellent. They are also
expected to permit occasional use at higher than normal thrust
levels. Early test results indicated that the engines would not
achieve all of the efficiency originally expected. NASA made
additional modifications, and it now expects to achieve most of the
originally predicted performance. However, as of May 1995, shuttle
program officials still considered the engine development status to
represent a threat to the lift gain expected from the enhancement
program.
An independent shuttle management review team also expressed concerns
with these two programs. In its report,\6 the team (1) concluded
that the new tank had the potential for problems during development
and manufacturing and (2) questioned using the improved engines for
increased thrust capability.
In addition to hardware redesign, NASA plans to incorporate flight
design and operation enhancements. These enhancements include the
use of more advanced navigational tools as well as software changes
to create a more efficient trajectory. The effect of achieving
greater efficiency during ascent is that less propellent would be
needed.
The most significant operational change involves the deletion of some
of the contingency fuel, water, oxygen, and other consumables. NASA
protects each mission by ensuring that there are sufficient
quantities of consumables to continue the mission in the event of
unexpected problems such as difficulties in docking and retrieving
payloads. In the past, it has been NASA's policy to cover nearly
every possible contingency. The new policy reduces the amount of
consumables by about 4,000 pounds per flight.
According to NASA, the revised approach will still ensure that
individual unexpected problems can be handled without jeopardizing
the mission. However, the reduction in consumables increases the
risk of mission failure if a combination of unexpected events occurs.
Under the new policy, for example, it might not be possible to
perform a second rendezvous with the station, if necessary, and, as a
worst case, it could be necessary to jettison a payload before
landing.
NASA believes the increase in risk is minimal and cites the new
policy as a means to reduce weight, increase lift, and save money.
In addition, it notes that the maximum reduction in consumables will
only be necessary on the heaviest of station flights. According to
the program director, this change helped make it possible to
terminate two of the more expensive enhancements--development of a
lightweight booster and extended motor nozzle--at a savings of about
$35 million.
To support the first shuttle space station launch, all of the
enhancement programs must be integrated and recertified into the
shuttle system within a demanding schedule. NASA has developed a
systems integration plan identifying the major events and schedules
associated with the shuttle enhancement program, as currently
approved. The plan describes over
200 individual events related to the development and integration of
shuttle lift-increasing modifications. The events began in early
calendar year 1994, and they will end with the first space station
flight, which is scheduled for December 1997.
The single most critical event is the delivery of the super
lightweight tank, and, according to the chief engineer of the shuttle
integration office, it is on a very success-oriented schedule that
has already experienced some delays. While the tank's critical
design review has already been held, the final set of design loads
are still being updated. Thus, many design and environment
definition activities will occur in parallel. If any of the assumed
design loads substantially change, additional certification cycles
may have to be conducted. However, there is no schedule or budget
margin that allows for major adjustments because the first tank is to
be delivered only 2 to 3 months before the first launch.
--------------------
\2 NASA defines hardware design as subsystem configuration. It
defines flight design as the way the vehicle is flown, and flight
operations as the usage of consumables such as propellent and water.
\3 Design loads are forces or pressures imposed on the shuttle during
various parts of its mission such as launch, ascent, and landing.
\4 The shuttle system includes an aircraft portion--the orbiter--and
propulsion components.
\5 The main engine improvements are not included in the list of
baselined enhancements since they were initiated to improve safety
margins. However, their availability for space station flights is
required in the overall strategy.
\6 NASA, Report of the Space Shuttle Management Independent Review
Team, February 1995.
SHUTTLE'S ABILITY TO SUPPORT
STATION'S ASSEMBLY SCHEDULE IS
QUESTIONABLE
------------------------------------------------------------ Letter :4
Based on its launch history and projected budget, the shuttle may not
be able to meet the demanding launch requirements of the space
station's assembly schedule. To meet the station's "assembly
complete" milestone, shuttle officials have designed a very
compressed launch schedule.
During certain periods of the station's assembly, clusters of shuttle
flights are scheduled to be launched within very short time frames.
The schedule calls for five launches within a 6-month period in
fiscal year 2000 and seven flights during a 9-month period in fiscal
year 2002. On two other occasions, three launches are scheduled in a
3-month period. This schedule equates to about 1 launch per month,
or a rate of up to
12 flights a year for these periods. In addition, on two occasions,
the schedule calls for launches of two missions with less than 35
days separating them. While NASA has achieved similar launch rates a
few times, it will have fewer processing personnel during the space
station era.
The space station's flight rate frequency cannot be met unless the
orbiter is processed in 20 to 30 days less than standard.\7 To
process the orbiter at this rate, shuttle personnel will have to work
overtime. However, according to operations officials, budget
constraints could make it difficult to fund overtime.
Because the schedule is so compressed at times, there is very little
margin for error. According to shuttle and station officials, there
is little flexibility in the schedule to meet major contingencies,
such as late delivery of station hardware, or technical problems with
the orbiters. Between December 1991 and September 1994, 9 of 22
shuttle flights slipped from the planned launch dates established 6
months before launch. The shuttle program maintained its annual
flight rate, in part, by launching payloads out of sequence.
However, during station assembly, most payloads must be launched in
the established sequence. The Shuttle Program Director told us that
he recognizes the launch schedule is tight and that if a significant
delay occurs with any station flight, subsequent flights are likely
to slip also.
The shuttle program will be attempting to accomplish the demanding
station assembly schedule with fewer resources than were available in
the past. For example, to reduce operating costs, NASA has reduced
the shuttle processing workforce at Kennedy Space Center by 1,400
people, or 20 percent, since 1992. According to a February 1995
internal workforce review, schedule risk already exists in areas such
as engine testing, crew training, and flight software development,
and NASA plans further funding cuts in the future. According to
shuttle processing officials, NASA will reduce the shuttle processing
workforce by another 900 people, or 15 percent, through fiscal year
2000. NASA continues to review all elements of shuttle operations to
improve processes and increase efficiency and believes that these
savings are achievable.
At the time of the fiscal year 1996 budget request, estimated shuttle
operations funding requirements exceeded projected budgets by at
least 10 percent--a cumulative total of $1.3 billion--in fiscal years
1996 through 2000. Shuttle managers were concerned about their
ability to achieve the additional funding cuts needed to meet the
projected budgets. In February 1995, independent review teams
recommended additional ways to reduce shuttle operations costs. NASA
does not have an estimate of savings that may result from
implementing the recommendations. According to the Director of
Shuttle Management and Operations at Kennedy Space Center, the
station's assembly schedule will slip unless (1) NASA provides
additional funds for shuttle operations or (2) more efficiencies are
found.
Officials in the Office of Space Flight told us that they estimated
that there is a medium to high risk that the station's assembly
completion date will slip because of shuttle delays. These officials
estimated that the schedule could slip about 4 to 5 months. Their
estimate was based on the fact that the shuttle achieved one less
flight than planned in 2 of the past 4 years.
A recent internal NASA study acknowledges the possibility of a slip
in the schedule. According to the April 1995 study conducted for the
International Space Station Independent Assessment Office at Johnson
Space Center, the shuttle cannot support the planned schedule unless
additional launch resources are provided or shuttle processing
methods are streamlined. The study identified a possible slip of up
to 4 years in completing station assembly due to shuttle processing
delays and the relatively low reliability of the Russian Zenit launch
vehicle. According to the study, shuttle processing presents the
largest schedule risk. To meet the manifest, NASA would have to
reduce processing time to 50 percent of current levels.
A delay in completing the space station assembly would increase the
station's cost because fixed costs would be continued for a longer
period. No reliable estimate of the increased cost exists since the
estimate would depend on the length of the delay and assumptions
about how long the station would remain operational after assembly is
complete. However, when NASA redesigned the station in 1994,
officials estimated the redesign would reduce costs by $1.6 billion
because it would accelerate the assembly complete date by 15 months,
from September 2003 to June 2002. At a minimum, a portion of these
savings would be lost if the assembly complete date slips.
--------------------
\7 According to Kennedy Space Center's guidelines, standard
processing for the orbiter is about
127 calendar days--92 in the orbiter processing facility, 7 in the
vehicle assembly building, and 28 on the pad.
NASA PLANS TO DEFER SOME
ORBITER RECERTIFICATION
ACTIVITIES AND FORGO SYSTEM
TESTING
------------------------------------------------------------ Letter :5
NASA plans to defer some orbiter recertification activities and forgo
testing all of the changes in an integrated fashion. NASA is
confident that the maturity of the current system and existing
databases from earlier testing are sufficient to justify the current
approach.
To reduce costs, NASA plans to alter the depth of a previously
planned materials review. The review was to have been part of a
program to recertify the individual shuttle orbiters after
incorporating the performance enhancements for the space station
program. It would have provided specific and detailed assurance that
every piece of the orbiter structure could safely withstand the
aerodynamic environments during space station missions. The space
station mission environments are expected to be more stressing than
those of previous missions. The purpose of the materials review was
to identify and reevaluate those structural components that were
previously accepted even though they did not fully conform to design
specifications.
NASA currently plans to assess the impact of the new environments on
these components based on the design rather than the actual hardware.
A materials review will be performed on critical structures,
according to NASA. NASA officials also told us that they are
confident the streamlined recertification program will adequately
ensure that the orbiter will perform in all possible station era
environments. They noted that the orbiter now has a lengthy flight
history record, and the experience gained from those flights ensures
that the design changes made to support the space station will be
fully understood.
In addition, NASA does not plan to perform test firings of the
modified propulsion system in an integrated setting. Instead, the
agency plans to verify system performance based on individual
component testing and predictive analyses. A 1989 study performed
for the Stennis Space Center addressed the concept of integrated
system testing. The study cited the unpredictability of the
"interactive characteristics of the propulsion, structural, and
electrical systems" and concluded that propulsion system testing
should be considered even in cases of "existing designs modified to
accommodate one or more major system redesigns." The same study
noted, however, that the technology base for the shuttle propulsion
system is more advanced than for other vehicles, thus mitigating the
engineering risks.
NASA does not believe integrated system test firings are necessary in
this case. Program officials noted that the propulsion system's
design changes do not affect the way in which fluids and propellent
are moved throughout the system. As a result, they believe component
testing, coupled with inferential analysis and modeling of the whole
system, will suffice. In addition, program management officials
stated that the costs were too high to justify integrated test
firings, given the test results and analyses that would be available
without integrated tests.
NASA HAS NOT CHARTERED AN
INDEPENDENT REVIEW OF
ENHANCEMENT INTEGRATION
------------------------------------------------------------ Letter :6
Independent assessments provide objective overviews of complex
development programs and space missions and can create an incentive
for more rigorous internal review of the program. In establishing an
independent group to oversee space station program safety, for
example, NASA noted that "engineering products are improved by
independent technical peer review," and that such reviews do not
"reflect on the competence, motivations, or integrity" of those
responsible for implementing a program. NASA's recently completed
laboratory review also endorsed the concept of independent review in
situations where the need has been identified. The report, issued in
February 1995, cited the value of being in a position to take a more
objective view of issues and details. It also noted that the process
of independent assessment requires managers to "review their efforts
from a perspective that is hard to maintain in the day-to-day
sequence of events."
In the past, NASA has sometimes chartered independent assessments of
complex development programs and missions, including assessments of
some parts of the performance enhancement program such as the main
engine improvement program and the super lightweight tank
development. However, NASA has not requested an independent
assessment of the integrated shuttle performance enhancement program,
even though the integration program is complex--consisting of over
200 scheduled events, involving uncertainties such as
characterization of the aerodynamic environments the enhanced shuttle
will operate in, and containing departures from previous programmatic
strategies.
RECOMMENDATION
------------------------------------------------------------ Letter :7
We recommend that the Administrator of NASA establish an independent
review team to (1) assess NASA's systems integration plan for the
lift-increasing enhancements, (2) identify the associated technical
and programmatic risks, and (3) weigh the costs and benefits of
NASA's tight scheduling of shuttle flights to assemble the space
station.
AGENCY COMMENTS
------------------------------------------------------------ Letter :8
In commenting on a draft of this report, NASA concurred with our
recommendation and stated that it had initiated implementation. The
Aerospace Safety Advisory Panel has agreed to perform the independent
reviews. According to NASA, the panel will use expert outside
consultants to review the benefits and the technical and scheduling
risks considering the current and projected NASA budgets. NASA noted
that although the space station assembly schedule was demanding and
funding was tight, it was currently on schedule and within budget.
NASA's comments are presented in their entirety in appendix I, along
with our evaluation of them.
SCOPE AND METHODOLOGY
------------------------------------------------------------ Letter :9
We conducted our review at NASA Headquarters, Marshall Space Flight
Center, Johnson Space Center, and Kennedy Space Center. We examined
(1) shuttle enhancement documentation, (2) budgetary data, (3)
internal and external analyses regarding the shuttle program, (4)
shuttle manifests, (5) shuttle processing data, and (6) space station
assembly schedules. In addition, we interviewed officials from NASA
Headquarters, the shuttle program, and the space station program
regarding issues related to NASA's plan to support space station
assembly. These interviews included discussions with representatives
of the Astronaut Office at Johnson Space Center.
We performed our work between November 1994 and May 1995 in
accordance with generally accepted government auditing standards.
Unless you publicly announce the contents of this report earlier, we
plan no further distribution of it until 15 days from its issue date.
At that time, we will send copies of it to the Administrator, NASA;
the Director, Office of Management and Budget; and other appropriate
congressional committees. We will also provide copies to others upon
request.
Please contact me on (202) 512-8412 if you or your staff have any
questions concerning this report. Major contributors to this report
were Lee Edwards, John Gilchrist, and Reginia Grider.
Sincerely yours,
David R. Warren
Director, Defense Management
and NASA Issues
(See figure in printed edition.)Appendix I
COMMENTS FROM THE NATIONAL
AERONAUTICS AND SPACE
ADMINISTRATION
============================================================== Letter
(See figure in printed edition.)
(See figure in printed edition.)
The following are our comments on the National Aeronautics and Space
Administration's (NASA) letter dated June 23, 1995.
GAO COMMENTS
----------------------------------------------------------- Letter :10
1. We have incorporated NASA officials informal comments in the text
where appropriate.
2. Although the development programs have not experienced
significant schedule slips to date, the programs have experienced
some early development problems and an independent management review
team concluded in February 1995 that the largest of these
programs--the super lightweight tank--had the potential for further
problems during development and manufacture. As we note on page 5,
NASA deleted two expensive hardware programs by substituting
operational changes that substantially reduced weight but increased
the risk of mission failure.
3. The April 1995 study was intended to identify the shuttle
program's challenge in supporting the station assembly schedule and
provide an indication of the possible magnitude of schedule slips.
Study officials told us that the conversion from workdays to calendar
days or use of available overtime would not substantially change the
study results. The study was based on actual timelines experienced
since the shuttle returned to flight after the Challenger accident.
NASA has not defined the streamlined payload checkout and orbiter
processing approaches that it says will be in place beginning in
1998. The impact of streamlining on the shuttle's launch schedule
cannot be determined at this time.
Subsequent to commenting on the report, officials ran the study model
again, using processing times for only those missions launched in
fiscal years 1992 and subsequent, and omitting the two flights with
the longest processing times. In this scenario, the model predicted
a slip of over 1 year in the station assembly complete milestone,
assuming 100 percent reliability and an inflexible assembly sequence.
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