GAO

United States General Accounting Office

Report to the Chairman, Subcommittee 

on Defense, Committee on 

Appropriations, House of 

Representatives

February 2001 DEFENSE 

ACQUISITIONS

Space-Based Infrared 

System-low at Risk of 

Missing Initial 

Deployment Date

GAO-01-6

Page 1 GAO-01-6 SBIRS-low

Contents

Letter 3

Appendixes Appendix I: Space-Based Infrared System-low Program History 24

Appendix II: Technology Readiness Levels and Their Definitions 29

Appendix III: Comments From the Department of Defense 30

Appendix IV: GAO Contact and Staff Acknowledgments 33

Figures Figure 1: SBIRS-low Schedule for First Launch in Fiscal Year 2006 8

Figure 2: Evolutionary Development of SBIRS-low Software 13

Figure 3: Technology Readiness Levels of Critical SBIRS-low 

Subsystems at the Start of Program Definition and Risk 

Reduction 16

Figure 4: Original SBIRS-low Schedule for First Launch in Fiscal

Year 2006 25

Figure 5: Revised SBIRS-low Schedule for First Launch in Fiscal 

Year 2004 27

Abbreviations

DOD Department of Defense

SBIRS Space-Based Infrared System
Page 2 GAO-01-6 SBIRS-low
Page 3 GAO-01-6 SBIRS-low

United States General Accounting Office

Washington, D.C. 20548 Letr

February 28, 2001

The Honorable Jerry Lewis

Chairman, Subcommittee on Defense

Committee on Appropriations

House of Representatives

Dear Mr. Chairman:

The Department of Defense (DOD) considers missile defense to counter 

attacks from ballistic missiles, both long-range strategic and shorter-range 

theater missiles, to be critical to our national security. The Air Force is 

developing a new satellite system, called Space-Based Infrared System-low 

(SBIRS)-low, to expand DOD’s current infrared satellite capabilities for 

supporting ballistic missile defense. The ability to detect missile launches, 

track missiles throughout their flights, and counter these threats is 

essential to ballistic missile defense. The primary mission of SBIRS-low is 

to detect launches and track missile flights. SBIRS-low accomplishes this 

by using infrared sensors to detect the heat missiles radiate. DOD plans to 

begin launching SBIRS-low satellites in fiscal year 2006 and estimates the 

life-cycle cost1

 through fiscal year 2022 to be $11.8 billion. 

Because this system is planned to support the proposed National Missile 

Defense System as well as theater missile defense programs, you asked us 

to evaluate DOD’s plans and progress to acquire SBIRS-low. Specifically, we 

(1) evaluated the cost, schedule, and performance risks of the current 

acquisition schedule; (2) evaluated technical risks of the program; and

(3) determined whether DOD has assessed alternative approaches to 

SBIRS-low. For each of these tasks, we discussed the program with DOD 

and contractor officials and reviewed studies and reports regarding cost, 

schedule, performance, and technical risks as well as possible alternatives 

to the program. (See our scope and methodology section.)

Results in Brief The Air Force’s current SBIRS-low acquisition schedule is at high risk of 

not delivering the system on time or at cost or with expected performance. 

While the Air Force’s previous schedules for SBIRS-low provided for the 

results of a flight test of crucial satellite functions and capabilities to be 

1

 DOD defines life-cycle cost as all costs relating to research, development, production, 

deployment, operations, and support for a system.
Page 4 GAO-01-6 SBIRS-low

available to support the decision to enter satellite production, the current 

schedule does not provide such test results until over 5 years after 

production has started. If design changes are identified as a result of the 

test, these changes will have to be incorporated into satellites already 

under production, and parts that have already been purchased based on the 

initial design may become obsolete and replaced with new parts, increasing 

program costs and causing schedule delays. In addition, DOD traditionally 

schedules completion of all software 1 year before the first satellite of a 

new system is to be launched. However, due to an underestimation of the 

level and difficulty of this effort, completion of SBIRS-low software will not 

occur until over 3 years after the first satellites are to be launched, 

increasing the risk that the software may not be available when needed or 

perform as required.

SBIRS-low has high technical risks because some critical satellite 

technologies have been judged to be immature for the current stage of the 

program. Specifically, the SBIRS-low program office rated the maturity of 

five of six critical technologies at levels that constitute high risk that the 

technologies will not be available when needed.

DOD acquisition policy and procedures require that assessments be made 

of the cost and mission effectiveness of space systems to alternative 

terrestrial systems. Such an assessment seems prudent in light of the high 

risks associated with the SBIRS-low program. However, the Air Force has 

not analyzed or identified terrestrial alternatives to the SBIRS-low system 

because, according to Air Force Space Command officials, terrestrial 

alternatives do not exist. Nevertheless, studies on various aspects of the 

National Missile Defense system by the Ballistic Missile Defense 

Organization and other organizations have pointed out that alternatives to 

SBIRS-low may exist, such as sea- or land-based radar. 

In order to reduce the cost, schedule, performance, and technical risks in 

the SBIRS-low program, we are recommending that the Secretary of 

Defense take actions to (1) restructure the SBIRS-low acquisition schedule 

and (2) analyze and develop, as appropriate, alternatives to satisfy critical 

ballistic missile defense requirements in case SBIRS-low cannot be 

deployed when needed.

DOD generally agrees with the report’s findings and recommendations.
Page 5 GAO-01-6 SBIRS-low

Background Based on its experiences with the launching of short-range theater missiles 

by Iraq during the 1991 Persian Gulf War, DOD concluded that expanded 

theater missile warning capabilities were needed and it began planning for 

an improved infrared satellite sensor capability that would support both 

long-range strategic and short-range theater ballistic missile warning and 

defense operations. In 1994, DOD studied consolidating various infrared 

space requirements, such as for ballistic missile warning and defense, 

technical intelligence, and battlespace characterization,2

 and it selected 

SBIRS to replace and enhance the capabilities provided by the Defense 

Support Program. The Defense Support Program is a strategic surveillance 

and early warning satellite system with an infrared capability to detect 

long-range ballistic missile launches that has been operational for about

30 years. DOD has previously attempted to replace the Defense Support 

Program with the Advanced Warning System in the early 1980s; the Boost 

Surveillance and Tracking System in the late 1980s; the Follow-on Early 

Warning System in the early 1990s; and the Alert, Locate, and Report 

Missiles System in the mid-1990s. These attempts failed due to immature 

technology, high cost, and affordability issues. SBIRS is to use more 

sophisticated infrared technologies than the Defense Support Program to 

enhance the detection of strategic and theater ballistic missile launches 

and the performance of the missile-tracking function.

2

 Technical intelligence relates to assessments of activities such as foreign launch 

technology developments and arms control compliance, and battlespace characterization 

refers to activities such as battle damage assessment.
Page 6 GAO-01-6 SBIRS-low

The SBIRS development effort consists of two programs—SBIRS-high and 

SBIRS-low. SBIRS-high is to consist of four satellites operating in 

geosynchronous earth orbit3

 and sensors on two host satellites operating in 

a highly elliptical orbit.4

 SBIRS-high will replace Defense Support Program 

satellites and is primarily to provide enhanced strategic and theater 

ballistic missile warning capabilities. The SBIRS-high program includes the 

consolidation of the three existing Defense Support Program ground 

facilities—two overseas and one in the United States—at a single U.S. 

ground station to reduce operations and maintenance costs. The program 

is in the engineering and manufacturing development phase,5

 with a 

scheduled launch of the first SBIRS-high satellite in fiscal year 2005.6

The SBIRS-low program is currently in the program definition and risk 

reduction acquisition phase7

 and is expected to consist of about 24 

satellites in low earth orbit, but it could consist of more or less satellites, 

depending on the results of contractor cost and performance studies. The 

primary purpose of SBIRS-low is to support both national and theater 

missile defense by tracking ballistic missiles and discriminating between 

the warheads and other objects, such as decoys, that separate from the 

missile bodies throughout the middle portion of their flights. Its 

deployment schedule is tied to fiscal year 2010, the date when these 

capabilities are needed by the National Missile Defense System. According 

to DOD, the first SBIRS-low satellites need to be launched in fiscal 

year 2006 if full deployment is to be accomplished by fiscal year 2010. 

3

 A satellite in a geosynchronous orbit has a circular period of revolution that is equal to the 

period of the earth’s rotation about its axis, or 24 hours.

4

 A satellite in a highly elliptical orbit spends most of its time over a designated area of the 

earth, known as apogee dwell.

5

 This phase, focused on finalizing the system design and ensuring it is ready for production, 

consists of the steps necessary to translate the most promising design approach into a 

stable, producible, supportable, and cost-effective design; validate the manufacturing or 

production processes; and demonstrate system capabilities through testing.

6

 We also evaluated DOD’s plans and progress to acquire SBIRS-high and we plan to issue a 

separate report on this evaluation. 

7

 This phase consists of steps necessary to verify preliminary design and engineering, build 

prototypes, accomplish necessary planning, and fully analyze trade-off proposals. The 

objective is to validate the choice of alternatives and to provide the basis for determining 

whether to proceed into the next phase (engineering and manufacturing development) of 

the acquisition process.
Page 7 GAO-01-6 SBIRS-low

Due to the importance Congress has placed on the deployment of a 

National Missile Defense System, Congress has maintained a high level of 

interest in the SBIRS-low program and has included in legislative 

provisions dates by which the first satellites are to be launched and initial 

operational capability is to occur.8

 The National Defense Authorization Act 

for Fiscal Year 2000 is the latest expression of such interest. It defines, in 

section 231, the SBIRS-low baseline schedule as a program schedule that 

includes a first launch of a SBIRS-low satellite to be made during fiscal

year 2006. This provision also requires that before the Secretary of the Air 

Force makes any changes to the SBIRS-low baseline schedule he must 

obtain the approval of the Director of the Ballistic Missile Defense 

Organization.9

SBIRS-low Program 

Employs a High-Risk 

Acquisition Strategy

The Air Force’s current SBIRS-low acquisition schedule is at high risk of 

not delivering the system on time or at cost or with expected performance. 

Specifically, satellite development and production are scheduled to occur 

concurrently and the results of a 1-year flight test that is to test and finalize 

the design of the satellites will not be available until more than 5 years after 

the program enters production. The software required for SBIRS-low to 

perform all its missions is to be developed concurrent with the deployment 

of the satellites and is not to be completed until more than 3 years after the 

first SBIRS-low satellites are to be launched.

On-Orbit Test Results Will 

Not Be Available to Support 

Production Decision

Under the Air Force’s previous schedules for SBIRS-low, the results of an 

on-orbit flight demonstration of crucial satellite functions and capabilities 

were to be available and used to support the decision to enter satellite 

production; however, the current schedule does not provide such test 

results in time to support the production decision. In February 1999, the Air 

Force established the current acquisition schedule (see fig.1) for the 

SBIRS-low program, which includes a program definition and risk 

reduction phase, a concurrent development and production phase, and 

8

 National Defense Authorization Act for Fiscal Year 1996, P. L. 104-106, section 216.

9

 Section 231 also specifies that such approval be obtained before the Secretary of the Air 

Force (1) establishes any system level technical requirement or makes any change to any 

such requirement or (2) makes any change to the budget baseline identified in the fiscal year 

2000 future years defense program.
Page 8 GAO-01-6 SBIRS-low

a 1-year on-orbit test with the first six SBIRS-low satellites produced (to be 

launched with two launches—three satellites per launch). 

Figure 1: SBIRS-low Schedule for First Launch in Fiscal Year 2006

Source: Air Force.

Program Definition

and Risk Reduction

Engineering and

Manufacturing

Development

Production

Initial launches

1-year on-orbit test

Remaining launches

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Fiscal Year

1 2

3 4 5 6 7 8 9 10
Page 9 GAO-01-6 SBIRS-low

The decision to enter the engineering and manufacturing development 

phase and production phases10 is to be made in the third quarter of fiscal 

year 2002. The 1-year on-orbit test, which is intended to test and finalize the 

design of the satellites, will not be completed until January 2008, more than 

5 years after development and production is to start. In contrast, under 

previous schedules (see app. I), the Air Force had stressed the importance 

of on-orbit tests, stating they were critical to support the decision to enter 

production. According to the Air Force, its decision to enter the 

engineering and manufacturing development and production phases will 

now be based on information obtained from the ground demonstrations 

performed under the program definition and risk reduction contracts and 

from other completed on-orbit demonstration programs such as the 

Midcourse Space Experiment and the Miniature Sensor Technology 

Integration Program.11 These program results, however, may be of limited 

utility to SBIRS-low. For example, according to Air Force officials, they 

plan to use information on midcourse discrimination collected by the 

Midcourse Space Experiment in their decision concerning SBIRS-low 

development and production. However, according to DOD’s Director of 

Operational Test and Evaluation, the Midcourse Space Experiment did not 

collect discrimination data on objects representative of those that 

SBIRS-low must be able to discriminate. 

10 This phase consists of the steps necessary to produce and deploy a system for operational 

use and ensure the system meets user’s needs. 

11 The Midcourse Space Experiment was the first demonstration in space of the technology 

(long-wave infrared) needed to identify and track ballistic missiles during the midcourse 

portion (between booster burnout and missile reentry) of their flight paths. The experiment 

collected data to characterize and identify missiles against space backgrounds. The 

Miniature Sensor Technology Initiative used several small satellites to demonstrate shortand mid-wave infrared technology, which is needed to identify missile launches and to track 

missiles while boosters are still burning.
Page 10 GAO-01-6 SBIRS-low

According to the Air Force, launches are not to be resumed until after the

1-year on-orbit test period has been completed, test results have been 

reviewed, and modifications, if required, have been made to the remaining 

satellites. However, the production of satellites will not stop during the

1-year on-orbit test. As a result, by the time the test is to be completed in 

fiscal year 2008, 9 satellites will have been produced (including the first 6 

used for flight-testing), an additional 21 satellites will be in various stages 

of production, and at least $1.9 billion of the $2.4 billion (then-year) cost for 

these 30 satellites will have been expended or committed.12 Because the 

on-orbit test results for crucial functions and capabilities is not to be 

available until more than 5 years after the start of production, there is a risk 

that design changes will be required for satellites in production. For 

example, if parts that have already been purchased for the SBIRS-low 

operational satellites became obsolete because their acquisition was based 

on the initial system design, new parts may be required, program costs will 

increase, and the schedule will slip. Also, additional changes may be 

necessary to the satellite configuration that could affect not just long lead 

items, but also modifications may be required to satellite components 

already produced.

In a July 1999 memorandum to the Under Secretary of Defense for 

Acquisition and Technology, DOD’s Director of Operational Test and 

Evaluation expressed concern that the new (current) schedule eliminated 

critical on-orbit experiments that were to be conducted under the flight 

demonstration. The Director stated that while the restructured program 

schedule includes ground demonstrations that were previously lacking 

from the SBIRS-low program, considering the many technical challenges 

and high risk in the program, DOD must seek every opportunity to obtain 

early on-orbit experience. According to the Director, many of the functions 

and capabilities that must be demonstrated (and would have been 

demonstrated under the flight demonstration) before SBIRS-low exits the 

program definition and risk reduction phase and enters the engineering and 

manufacturing development phase are impossible to demonstrate with only 

ground tests. For example, the Director stated that DOD has no flight 

experience where two or more satellites in low earth orbit have 

communicated with each other. He stated that this was challenging 

12 While the system is to consist of a constellation of about 24 satellites, the program 

provides for the production of an additional 34 satellites to maintain this constellation size 

through fiscal year 2022. Therefore, the 30 satellites discussed here include the 24 for the 

initial constellation and 6 replenishment satellites. 
Page 11 GAO-01-6 SBIRS-low

because of the dynamically changing positions of orbiting satellites relative 

to each other and the high data rates needed to transmit data between 

satellites thousands of kilometers13 apart. Another example cited by the 

Director where DOD has no flight experience is with coordinating the 

operation of acquisition and tracking infrared sensors, both of which are to 

be mounted on each SBIRS-low satellite. Specifically, when the acquisition 

sensor detects the heat from a missile’s booster motor, it must determine 

and relay highly accurate information on the missile’s position to the 

tracking sensor. The tracking sensor must then point to the proper location 

in space, find the missile, and begin tracking the missile. All of these 

activities must occur within short time frames (seconds) to support missile 

defense.

We have reported on numerous occasions about the risks associated with 

program concurrency and of initiating production without adequate 

testing. In a 1990 testimony, we cited the Navy’s F/A-18 aircraft, the Air 

Force’s B-1B Bomber, and the Navy’s AEGIS Destroyer as examples where 

a rush to production without adequate testing resulted in increased costs, 

lower than expected performance, or both. In 1994 and 1995, we reported 

that programs are often permitted to begin production with little or no 

scrutiny and that the consequences have included procurement of 

substantial inventories of unsatisfactory weapons requiring costly 

modifications to achieve satisfactory performance, and in some cases, 

deployment of substandard systems to combat forces. In 2000, we reported 

that programs were allowed to begin production before the contractors and 

the government had conducted enough testing to know whether the 

systems’ design would meet requirements.14

13 One thousand kilometers equals 620 miles.

14 Weapon Systems: Concurrency in the Acquisition Process (GAO/T-NSIAD-90-43, May 17, 

1990); Weapons Acquisition: Low-Rate Initial Production Used to Buy Weapon Systems 

Prematurely (GAO/NSIAD-95-18, Nov. 21, 1994); Tactical Aircraft: Concurrency in 

Development and Production of F-22 Aircraft Should Be Reduced (GAO/NSIAD-95-59, 

Apr. 19,1995); Defense Acquisitions: Need to Revise Acquisition Strategy to Reduce Risk for 

Joint Air-to-Surface Standoff Missile (GAO/NSIAD-00-75, Apr. 26, 2000); and Missile Defense: 

Schedule for Navy Theater Wide Program Should Be Revised to Reduce Risk 

(GAO/NSIAD-00-121, May 31, 2000).
Page 12 GAO-01-6 SBIRS-low

Evolutionary Software 

Development Plan Increases 

Program Risk

In December 1999, the SBIRS-low program office concluded that 

development of software to perform all SBIRS-low missions, as originally 

scheduled, could not be completed 1 year before the scheduled first launch 

of SBIRS-low satellites in fiscal year 2006. According to the Air Force, this 

conclusion was based on lessons learned from other programs under which 

software development efforts were underestimated. As a result, to maintain 

the fiscal year 2006 first launch, the program office plans to use an 

evolutionary software development approach under which software is to 

be developed in increments. The software needed to support all SBIRS-low 

missions will not be completed (ready for use for satellite operations) until 

March 2010, over 3 years after the first satellites are launched. 

According to Air Force officials, DOD traditionally completes software 

required to support satellite systems 1 year before the scheduled first 

launch of a new satellite system. DOD established this practice to reduce 

risk by ensuring that all system problems have been identified and 

resolved, and that the personnel operating the systems have been 

adequately trained. This was the original plan for the SBIRS-low program. 

Under the evolutionary approach, software will be developed to support 

satellite launches, early on-orbit testing, ballistic missile defense, and 

integration with SBIRS-high, followed by the software needed to support 

ancillary missions, such as technical intelligence and battlespace 

characterization. Figure 2 shows the schedule for the incremental 

development and completion of the software relative to the launch and 

testing schedule for the SBIRS-low satellites. 
Page 13 GAO-01-6 SBIRS-low

Figure 2: Evolutionary Development of SBIRS-low Software

Source: Air Force.

As figure 2 shows, by the time the on-orbit test period for the first six 

SBIRS-low satellites is to begin in fiscal year 2007, the first two increments 

of software are to be completed. According to program office officials, 

these two increments of software will provide all of the capabilities the 

ground control system and the satellites need to support and perform the 

on-orbit test. The third increment, the ground control and space related 

software required to operate the full satellite constellation in support of 

ballistic missile defense, is not to be completed until fiscal year 2008. The 

fourth software increment, which is to be completed in mid-fiscal 

year 2009, is to integrate SBIRS-low with SBIRS-high. The fifth increment, 

which is to be completed in mid-fiscal year 2010, is to add the software 

required for SBIRS-low to perform ancillary missions such as technical 

Initial launches

1-year on-orbit test

Remaining launches

Software development increments:

1. Initial operations capability

required for launches

2005 2010 2006 2007 2008 2009

Fiscal Year

1 2

2. Added capability to support

satellite tests

3. Full ballistic missile defense

capability for entire

constellation

4. Full integration of SBIRSlow with SBIRS-high

5. Ancillary missions

345 67 8 9 10
Page 14 GAO-01-6 SBIRS-low

intelligence, battlespace characterization, and space surveillance. Thus, the 

software required to support all of SBIRS-low missions is not to be 

completed until over 3 years after the first satellites are launched. While 

this evolutionary approach reduces schedule pressure for completing the 

ground control and space software before the first launch in fiscal year 

2006, it increases the risk that software may not be available when needed 

or perform as required. Under the traditional approach, all software would 

have been completed in fiscal year 2005, 1 year before the launch of the 

first satellites. 

SBIRS-low Program 

Includes Immature 

Critical Technologies

The SBIRS-low program has high technical risks because some critical 

satellite technologies have been judged to be immature for the current 

stage of the program. Specifically, the SBIRS-low program office rated the 

maturity of five of six critical technologies at levels that constitute high risk 

the technologies will not be available when needed.

In developing a complex system, an assessment of the maturity levels of 

critical technologies can provide information on the risks those maturity 

levels pose if the technologies are to be included in the development. For 

example, in a previous report,15 we discuss a tool, referred to as Technology 

Readiness Levels, the National Aeronautics and Space Administration and 

Air Force Research Laboratory use to determine the readiness of 

technologies to be incorporated into a weapon system.16 The readiness 

levels are measured along a scale of one to nine, starting with paper studies 

of the basic concept and ending with a technology that has proven itself in 

actual usage on the intended product. The Air Force Research Laboratory 

considers a readiness level of six to be an acceptable risk for a program 

15 Best Practices: Better Management of Technology Development Can Improve Weapon 

System Outcomes (GAO/NSIAD-99-162, July 30, 1999). We concluded that the incorporation 

of advanced technologies before they are mature has been a major source of cost increases, 

schedule delays, and performance problems on weapon systems and recommended that the 

Secretary of Defense adopt a disciplined and knowledge-based approach of assessing 

technology maturity, such as Technology Readiness Levels, DOD-wide, and establish the 

point at which a match is achieved between key technologies and weapon system 

requirements as the proper point for committing to the development and production of a 

weapon system. In response, DOD agreed that Technology Readiness Levels can be used to 

help guide technology maturation and transition decisions.

16 The Air Force Research Laboratory is a science and technology organization that matures 

advanced technologies to the point that they can be included in weapon system programs 

and be expected to perform as required. The Laboratory uses the Technology Readiness 

Levels to assess the maturity of the technologies before they are handed off to programs.
Page 15 GAO-01-6 SBIRS-low

entering the Program Definition and Risk Reduction phase—the 

Laboratory considers lower readiness levels at this stage to translate to 

high program cost, schedule, and performance risks. Reaching a readiness 

level of six denotes a significant transition point for technology 

development in which the technology moves from component testing in a 

laboratory environment to demonstrating a model or prototype in a 

relevant environment.

At our request, the SBIRS-low program office rated the maturity, as of the 

start of the Program Definition and Risk Reduction phase, of six 

technologies critical to the success of the SBIRS-low program. The 

program office rated five of the six technologies at levels that, according to 

criteria used by the Air Force Research Laboratory, constitute high risk in 

the ability of the program to meet its objectives. A detailed description of 

the Technology Readiness Levels is provided in appendix II.

As shown in figure 3, SBIRS-low entered the Program Definition and Risk 

Reduction phase with a number of critical subsystem technologies with 

maturities below a readiness level of six.
Page 16 GAO-01-6 SBIRS-low

Figure 3: Technology Readiness Levels of Critical SBIRS-low Subsystems at the Start of Program Definition and Risk Reduction

Specifically, the program office rated the maturity of the (1) scanning 

infrared sensor, which is to acquire ballistic missiles in the early stages of 

flight, at a readiness level of four; (2) tracking infrared sensor, which is to 

track missiles, warheads, and other objects such as debris and decoys 

during the middle and later stages of flight, at a readiness level of four; 

(3) fore optics cryocooler and (4) tracking infrared sensor cryocooler, 

which are needed to cool the tracking sensor optics and other sensor 

components to enable the sensor to detect missile objects in space, at 

readiness levels of four; (5) satellite communications crosslinks, which 

enable satellites to communicate with each other, at a readiness level of 

five; and (6) on-board computer processors, critical for performing 

Scanning infrared sensor

Tracking infrared sensor

Fore optics cryocooler

Tracking infrared sensor cryocooler

1 6 2 3 4 5

Technology Readiness Levels

7

Satellite communications crosslinks

On-board computer processor

Goal
Page 17 GAO-01-6 SBIRS-low

complex and autonomous satellite operations for providing missile 

warning and location information within short time frames, at a level of six. 

So critical are each of these subsystem technologies is that if one is not 

available when needed, SBIRS-low would be unable to perform its mission. 

And, in sum, five of six critical technologies are at a low maturity level, 

causing high program risk.

Alternative 

Approaches to 

SBIRS-low Have Not 

Been Assessed

Current DOD acquisition policy and procedures require that assessments 

be made of the cost and mission effectiveness of space systems to 

alternative terrestrial—land, sea, and air—systems.17 Despite this 

requirement, DOD has not adequately analyzed or identified cost-effective 

alternatives to SBIRS-low that could satisfy critical missile defense 

requirements such as a Navy ship-based radar capability. Compliance with 

this requirement would seem especially important, given the high risks 

identified with the SBIRS-low program.

Terrestrial alternatives to SBIRS-low are not being considered. While 

competing SBIRS-low contractors are performing cost and trade studies on 

the various options that could satisfy program requirements, none of these 

studies is to consider the cost-effectiveness of terrestrial alternatives. The 

most recent study assessing alternatives to SBIRS-low was performed in 

1994;18 however, according to an Air Force Space Command official, the 

study’s scope was focused only on options that would use space-based 

infrared sensors; terrestrial options were not included. According to Air 

Force Space Command officials, terrestrial alternatives to SBIRS-low do 

not exist.

17 Department of Defense Directive 5000.1, Defense Acquisition, March 15, 1996; Department 

of Defense Regulation 5000.2-R, Mandatory Procedures for Major Defense Acquisition 

Programs (MDAPs); and Major Automated Information System (MAIS) Acquisition 

Programs, May 11, 1999. In addition, in commenting on a recent report in which we 

evaluated the extent to which plans for expanding military space systems conform to 

national and defense space policies (Defense Acquisitions: Improvements Needed in 

Military Space Systems’ Planning and Education (GAO/NSIAD−00-81, May 18, 2000)), DOD 

stated that program assessments should highlight the relative advantages and disadvantages 

of a full range of alternatives, both space- and terrestrial-based alternatives.

18 This study was referred to as the Office of the Secretary of Defense Space-Based Warning 

Summer Study. The Summer Study was initiated to consolidate infrared space requirements 

and resulted in SBIRS being selected to replace the Defense Support Program. 
Page 18 GAO-01-6 SBIRS-low

Studies on various aspects of the National Missile Defense System by the 

Ballistic Missile Defense Organization and other organizations have 

pointed out that alternatives to SBIRS-low may exist. For example, the 

Ballistic Missile Defense Organization’s June 1999 study, which assessed 

whether and how the Navy Theater Wide program, a DOD program to 

develop a ship-based theater missile defense capability, could be upgraded 

to provide a limited national missile defense capability,19 cited the potential 

utility of sea-based radars to a national missile defense capability. 

Specifically, the report states that properly deployed ship-based radars can 

provide a forward-based radar warning and tracking function against many 

of the potential ballistic missile threats to the United States, and that 

because the radars would be difficult to target due to the mobility and 

unknown locations of ships, the radars would add robustness against 

enemy attacks, particularly before SBIRS-low is available.

In a 1999 RAND issue paper that dealt with an assessment of the planning 

for the National Missile Defense System, the authors suggest that 

ground-based radars could potentially be used to provide midcourse 

tracking and cueing for interceptors.20 Specifically, they conclude that the 

planned initial capability of the National Missile Defense System is 

inadequate and suggest that an interim solution be considered to enhance 

the system’s capabilities against more sophisticated, larger, and more 

geographically dispersed ballistic missile threats prior to the next planned 

enhancement to the missile defense system. They suggest that one aspect 

of the interim solution could include deploying additional ground-based 

radars to perform ballistic missile tracking and discrimination functions, or 

alternately, speeding the deployment of SBIRS-low. 

Conclusions The Air Force is implementing a high-risk acquisition schedule for the 

SBIRS-low program in an attempt to deploy the system starting in fiscal 

year 2006 to support the National Missile Defense System. The highly 

concurrent acquisition schedule has evolved because of design, 

development, and technology challenges, as well as the importance 

Congress has placed on the deployment of a National Missile Defense 

19 Summary of Report to Congress on Utility of Sea-Based Assets to National Missile 

Defense, Ballistic Missile Defense Organization (June 1999).

20 Planning a Ballistic Missile Defense System of Systems: An Adaptive Strategy, RAND, 

National Defense Research Institute (1999).
Page 19 GAO-01-6 SBIRS-low

capability. Although the schedule includes on-orbit tests to finalize satellite 

design and performance, the results will not be available in time to be 

useful for informed decision-making related to satellite design and 

production. 

In addition, the Air Force’s evolutionary software development approach 

creates risk because it delays completion of the software needed to support 

all SBIRS-low missions over 3 years after the first launch of SBIRS-low 

satellites. 

Finally, critical satellite technologies that have been judged to be immature 

for the current phase of the program, place program success in peril. 

Due to these deficiencies, the SBIRS-low program is at high risk of not 

delivering the system on time or at cost or with expected performance. In 

spite of the high risk that SBIRS-low will not be available to support the 

National Missile Defense System when needed, DOD has not identified 

alternatives or interim solutions. 

Recommendations for 

Executive Action

In order to reduce the cost, schedule, performance, and technical risks in 

the SBIRS-low program, we recommend that the Secretary of Defense 

direct the Secretary of the Air Force, with the approval of the Director of 

the Ballistic Missile Defense Organization, to develop a schedule that 

reduces concurrency and risks, and that sets more realistic and achievable 

cost, schedule, and performance goals. In addition, the Secretary of 

Defense should assess the impact of the revised schedule on the National 

Missile Defense program and provide the results of the assessment to 

Congress. 

We also recommend that the Secretary of Defense direct the Director, 

Ballistic Missile Defense Organization, to analyze and develop, as 

appropriate, and in compliance with DOD acquisition policy and 

procedures, alternative approaches to satisfy critical missile defense 

midcourse tracking and discrimination requirements in case SBIRS-low 

cannot be deployed when needed (based on the resulting lower risk 

SBIRS-low schedule, threat analyses, and missile defense program 

schedules).
Page 20 GAO-01-6 SBIRS-low

Agency Comments and 

Our Evaluation

In written comments to a draft of this report, DOD generally agreed with 

our recommendations. DOD also pointed out that it is taking actions that it 

believes will address our recommendations. These actions begin to address 

our concerns, but they are not yet completed or approved, and it is not 

clear yet whether they will fully address the risks identified by our review. 

Therefore, our recommendations are still relevant. 

Our first recommendation deals with restructuring the SBIRS-low 

acquisition schedule to reduce cost, schedule, performance, and technical 

risks; assessing the impact of the restructured schedule on the National 

Missile Defense program; and providing the results of the assessment to 

Congress. DOD stated it has developed a proposed update to the 

SBIRS-low acquisition strategy that it believes addresses our concerns for 

concurrency in the production phase, while still retaining the fiscal 

year 2006 first launch date. For example, DOD’s proposed strategy would 

delay the full operational capability date of the first SBIRS-low 

constellation by 1 year and allow for additional ground demonstration 

program activities and on-orbit testing, thus reducing concurrency between 

production and testing, while maintaining the schedule for implementation 

of the full constellation. DOD stated that the Ballistic Missile Defense 

Organization is assessing the impact of this delay on the National Missile 

Defense program. This proposal has not been approved and will be 

reviewed for final decision by the Under Secretary of Defense for 

Acquisition, Technology, and Logistics in May 2001.

Since DOD’s proposed update to the SBIRS-low acquisition strategy has not 

been approved (due to cost concerns) and will not be considered again for 

approval until May 2001, we did not assess the proposed strategy in any 

detail. On the surface, the additional on-orbit testing does somewhat 

reduce production concurrency. However, even with this additional testing, 

the program still appears to have high concurrency risk, for example, with 

substantial long lead time procurement before testing results are complete. 

Therefore, we believe our recommendation is still appropriate in relation to 

the new proposal or in light of any changes to DOD’s new proposal. 

With regard to our second recommendation, DOD stated that it has 

initiated a study to address viable alternatives to SBIRS-low capabilities 

and will provide the results of the study to the Deputy Secretary of Defense 

on March 1, 2001. While initiation of this study is a good beginning, until it 

is complete, we cannot assess the extent to which alternatives will be 
Page 21 GAO-01-6 SBIRS-low

identified and whether critical missile defense requirements allocated to 

SBIRS-low will be satisfied. 

DOD’s comments are reprinted in appendix III. DOD also provided separate 

technical comments that we have incorporated in this report where 

appropriate.

Scope and 

Methodology

To evaluate risks of the current acquisition schedule, we had discussions 

with officials of the Under Secretary of Defense for Acquisition, 

Technology, and Logistics; the Under Secretary of Defense for the 

Comptroller; the Assistant Secretary of Defense for Command, Control, 

Communications, and Intelligence; the Office of the Director, Operational 

Test and Evaluation; the Office of Program Analysis and Evaluation; and 

the Assistant Secretary of the Air Force for Acquisition, all in Washington, 

D.C. We also held discussions with, and reviewed documents from, officials 

of the SBIRS program office in Los Angeles, California; the U.S. and Air 

Force Space Commands, Colorado Springs, Colorado; the Defense 

Contract Management Agency offices in Van Nuys, California, and Phoenix, 

Arizona; the Air Force Operational Test and Evaluation Center, Buckley Air 

National Guard Base, Aurora, Colorado; TRW, Inc., Redondo Beach, 

California; and Spectrum Astro, Gilbert, Arizona. 

To evaluate technical risks of the program, we had discussions with, and 

reviewed documents from, officials of the program office; the Office of the 

Director, Operational Test and Evaluation; and the Air Force Research 

Laboratory, Albuquerque, New Mexico. We also discussed technical risks 

with TRW and Spectrum Astro.

To determine whether DOD has assessed alternative approaches to 

SBIRS-low, we had discussions with the Ballistic Missile Defense 

Organization, in Washington, D.C.; the program office; and U.S. and Air 

Force Space Commands. We also reviewed two related studies by the 

Ballistic Missile Defense Organization and the RAND Corporation.

We performed our work from May 1999 through December 2000 in 

accordance with generally accepted government auditing standards.
Page 22 GAO-01-6 SBIRS-low

If you or your staff have any questions concerning this report, please call 

me on (404) 679-1900. The GAO contact and staff acknowledgments are 

listed in appendix IV.

Sincerely yours,

Louis J. Rodrigues

Director, Defense Acquisitions Issues
Page 23 GAO-01-6 SBIRS-low
Page 24 GAO-01-6 SBIRS-low

Appendix I

Space-Based Infrared System-low Program Apendxies

History ApendxiI

Original Schedule The Department of Defense’s (DOD) original 1995 schedule for 

Space-Based Infrared System-low (SBIRS)-low called for (1) a launch of a 

two-satellite flight demonstration—both satellites on one launch 

vehicle—in the first quarter of fiscal year 1999; (2) a deployment decision 

in fiscal year 2000 after key technologies and operating concepts were 

validated by the demonstration satellites; and (3) launches of SBIRS-low 

satellites—3 satellites per launch vehicle—beginning in fiscal year 2006.

According to Air Force officials, the satellite flight demonstration was 

critical to validate the integration of key technologies and operational 

concepts that are crucial to national missile defense and other SBIRS 

missions such as technical intelligence and battlespace characterization. 

The primary emphasis was to be on the ability to detect and track ballistic 

missiles and their warheads throughout flight and distinguish between 

missile warheads and decoys. The Air Force planned to test these satellites’ 

ability to perform national missile defense functions against live theater 

and national missile defense targets and to use the demonstration and test 

results to model and simulate the full performance capability of a 

constellation of operational SBIRS-low satellites. 

According to the program officials who established this acquisition 

strategy, performing this function autonomously while in orbit is one of the 

most complex and technologically challenging operational concepts ever 

attempted. They also stressed that the two-flight demonstration satellites 

would have provided an informed basis for deciding whether the program 

was ready to enter the engineering and manufacturing development and 

production phases of the acquisition process. They stated that a National 

Missile Defense System with space-based sensors depended on a 

successful flight demonstration program and that proceeding into the 

engineering and manufacturing development and production phases before 

demonstrating this capability would not provide an opportunity to assess 

lessons learned, thus introducing unacceptable risk into the program.

Figure 4 shows the original acquisition schedule for a fiscal year 2006 first 

launch of SBIRS-low satellites. 
Appendix I

Space-Based Infrared System-low Program 

History

Page 25 GAO-01-6 SBIRS-low

Figure 4: Original SBIRS-low Schedule for First Launch in Fiscal Year 2006

Source: Air Force.

Under this schedule, the first year of the planned 2-year flight 

demonstration would have been completed in the first quarter of fiscal

year 2000, about the same time the program was scheduled to enter the 

pre-engineering and manufacturing development phase. The first year 

results from the demonstration could have influenced requirements 

development and system design during this phase. The second year of the 

demonstration would have been completed in the first quarter of fiscal 

year 2001, about the same time the program was scheduled to enter the 

engineering and manufacturing development and production phases. Thus, 

DOD would have had almost 2-years of information on the demonstration 

satellites’ performance to consider in deciding whether the system should 

Flight Demonstration

− Development

Pre-Engineering and

Manufacturing

Development

Engineering and

Manufacturing

Development and

Production

Launch

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009

Fiscal Year

− Launch

− Demonstration Year 1 Year 2

2010
Appendix I

Space-Based Infrared System-low Program 

History

Page 26 GAO-01-6 SBIRS-low

enter the engineering and manufacturing development and production 

phases.

Accelerated Schedule 

Established in 

December 1996

DOD did not implement the original schedule because Congress required in 

the National Defense Authorization Act for Fiscal Year 1996 that DOD 

establish a program baseline to include a first launch of SBIRS-low 

satellites in fiscal year 2002.1

 The Defense Science Board, at DOD’s request, 

assessed the viability of accelerating the first launch from fiscal year 2006 

to fiscal year 2002 and found it would not be viable; however, it did 

determine that the first launch could be accelerated to fiscal year 2004.2

Subsequently, DOD informed Congress that the first launch of SBIRS-low 

satellites could not begin in fiscal year 2002 because technical, funding, and 

management problems had delayed the scheduled launch of the two 

demonstration satellites from the first quarter to the third quarter of fiscal 

year 1999. According to Air Force officials, this delay prevented basing a 

milestone decision to enter the engineering and manufacturing 

development and production phases of the SBIRS-low acquisition process, 

scheduled for the first quarter of fiscal year 2000, on the results of the 

planned flight demonstration. However, in December 1996, DOD 

committed to accelerating the first launch of SBIRS-low satellites to fiscal 

year 2004. Figure 5 shows the acquisition schedule for the flight 

demonstration and a fiscal year 2004 first launch of SBIRS-low. 

1

 P. L.104-106, section 216. 

2

 In 1996, we also assessed various SBIRS-low deployment options and identified the cost 

and the risks associated with each option, including the option DOD selected. We 

recommended that DOD provide Congress with complete, consistent, and current 

information regarding all of the deployment options it considered. See National Missile 

Defense: Risk and Funding Implications for the Space-Based Infrared Low Component

(GAO/NSIAD-97-16, Feb. 25, 1997).
Appendix I

Space-Based Infrared System-low Program 

History

Page 27 GAO-01-6 SBIRS-low

Figure 5: Revised SBIRS-low Schedule for First Launch in Fiscal Year 2004

Source: Air Force.

Under this acquisition schedule, the demonstration satellites were to be 

launched in the third quarter of fiscal year 1999, two quarters later than 

scheduled under the original schedule. Consequently, the flight 

demonstration and the pre-engineering and manufacturing development 

phase would have run concurrently and the demonstration results could 

not have influenced the development of requirements and the system 

design as they could have under the original schedule. However, the first 

year of the flight demonstration would still have been completed about 

4 months before the start of the engineering and manufacturing 

development and production phases, which were still scheduled to begin in 

the first quarter of fiscal year 2001 as they were under the original 

Flight Demonstration

− Development

Pre-Engineering and

Manufacturing

Development

Engineering and

Manufacturing

Development and

Production

Launch

1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010

Fiscal Year

− Launch

− Demonstration Year 1 Year 2
Appendix I

Space-Based Infrared System-low Program 

History

Page 28 GAO-01-6 SBIRS-low

schedule. As a result, DOD would have had the information from the first 

year of the demonstration satellites’ performance, which it considered the 

most critical in deciding whether the system should enter these phases, to 

support a fiscal year 2004 deployment.
Page 29 GAO-01-6 SBIRS-low

Appendix II

Technology Readiness Levels and Their 

Definitions ApendxiI

Source: Best Practices: Better Management of Technology Development Can Improve Weapon 

System Outcomes (GAO/NSIAD-99-162, July 30, 1999).

Technology readiness level Description

1. Basic principles observed and 

reported.

Lowest level of technology readiness. Scientific research begins to be translated into applied 

research and development. Examples might include paper studies of a technology’s basic 

properties.

2. Technology concept and/or 

application formulated.

Invention begins. Once basic principles are observed, practical applications can be invented. 

The application is speculative, and there is no proof or detailed analysis to support the 

assumption. Examples are still limited to paper studies.

3. Analytical and experimental critical 

function and/or characteristic proof 

of concept.

Active research and development is initiated. This includes analytical studies and laboratory 

studies to physically validate analytical predictions of separate elements of the technology. 

Examples include components that are not yet integrated or representative. 

4. Component and/or breadboard 

validation in laboratory 

environment.

Basic technological components are integrated to establish that the pieces will work together. 

This is relatively “low fidelity” compared to the eventual system. Examples include integration 

of “ad hoc” hardware in a laboratory. 

5. Component and/or breadboard 

validation in relevant environment.

Fidelity of breadboard technology increases significantly. The basic technological components 

are integrated with reasonably realistic supporting elements so that the technology can be 

tested in a simulated environment. Examples include “high fidelity” laboratory integration of 

components. 

6. System/subsystem model or 

prototype demonstration in a 

relevant environment.

Representative model or prototype system, which is well beyond the breadboard tested for 

technology readiness level 5, is tested in a relevant environment. Represents a major step up 

in a technology’s demonstrated readiness. Examples include testing a prototype in a high 

fidelity laboratory environment or in simulated operational environment.

7. System prototype demonstration in 

an operational environment.

Prototype near or at planned operational system. Represents a major step up from technology 

readiness level 6, requiring the demonstration of an actual system prototype in an operational 

environment, such as in an aircraft, vehicle, or space. Examples include testing the prototype 

in a test bed aircraft.

8. Actual system completed and “flight 

qualified” through test and 

demonstration.

Technology has been proven to work in its final form and under expected conditions. In almost 

all cases, this technology readiness level represents the end of true system development. 

Examples include developmental test and evaluation of the system in its intended weapon 

system to determine if it meets design specifications.

9. Actual system “flight proven” 

through successful mission 

operations. 

Actual application of the technology in its final form and under mission conditions, such as 

those encountered in operational test and evaluation. In almost all cases, this is the end of the 

last “bug fixing” aspects of true system development. Examples include using the system 

under operational mission conditions.
Page 30 GAO-01-6 SBIRS-low

Appendix III

Comments From the Department of Defense ApendxiI

Note: GAO comments 

supplementing those in the 

report text appear at the 

end of this appendix.

See comment 1.

See comments 2 and 3.
Appendix III

Comments From the Department of Defense

Page 31 GAO-01-6 SBIRS-low

Now on p. 19.

Now on p. 19.

Now on p. 19.
Appendix III

Comments From the Department of Defense

Page 32 GAO-01-6 SBIRS-low

The following are our comments on DOD’s letter dated December 14, 2000.

GAO Comments 1. We are cognizant of the fact that the National Missile Defense program 

is driving the need date for SBIRS-low and not the converse. We do not 

intend to suggest that the SBIRS-low acquisition schedule be a driver 

for the National Missile Defense program schedule. Our primary goal in 

making this recommendation is to help ensure SBIRS-low is acquired at 

lower risk and will satisfy critical missile defense requirements. This is 

why we are also making our second recommendation—to develop 

alternative approaches to satisfy critical missile defense midcourse 

tracking and discrimination requirements in case SBIRS-low (under a 

new lower risk schedule) cannot be deployed when needed. 

2. We disagree that we misstate the risks of the SBIRS-low incremental 

software development strategy. We recognize that an evolutionary, or 

incremental, approach to software development is valid. However, an 

acquisition approach such as the original SBIRS-low approach that 

calls for the completion of all software prior to the first launch poses 

less risk than one that does not, that is, the evolutionary or current 

approach. From the perspective of meeting the schedule for a first 

launch in fiscal year 2006, the evolutionary software development 

approach may reduce schedule risk because, according to the Air 

Force, the first launch date would be unachievable under the original 

strategy due to an underestimation of the software development effort. 

However, from the perspective of comparing the evolutionary software 

development approach with the original approach, there is increased 

program risk associated with the evolutionary approach because there 

is less assurance the software will be completed when needed with the 

mission capabilities specified.

3. While we agree that a revised acquisition strategy would likely increase 

costs, cost increases associated with program delays or rework could 

also occur under the current schedule. Due to the highly concurrent 

acquisition schedule, we believe that there is substantial risk that 

delays and rework resulting from the production of hardware and 

software that fail to satisfy requirements may occur—resulting in cost 

increases if the current schedule is strictly adhered to. We believe that 

early effort to understand acquisition options and the associated costs 

is important.
Page 33 GAO-01-6 SBIRS-low

Appendix IV

GAO Contact and Staff Acknowledgments ApendxiIV

GAO Contact James H. Solomon (303) 572-7315

Staff 

Acknowledgments

In addition to the person named above, Ted B. Baird, Richard Y. Horiuchi, 

and Robert W. Stewart of the Denver Field Office and David G. Hubbell and 

Dale M. Yuge of the Los Angeles Field Office made key contributions to this 

report.

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