MARCH 29, 2010

REVIEW REPORT

REPORT NO. IG-10-011 (ASSIGNMENT NO. S-09-010-00)

OFFICE OF AUDITS

REVIEW OF THE CONSTELLATION PROGRAM’S 

REQUEST TO DISCONTINUE USING THE 

METRIC SYSTEM OF MEASUREMENT

OFFICE OF INSPECTOR GENERAL

National Aeronautics and 

Space Administration
REPORT NO. IG-10-011

Final report released by:

/signed/

Paul K. Martin

Inspector General 

Acronyms

DoD Department of Defense 

EO Executive Order

FY Fiscal Year

ISS International Space Station

NIST National Institute of Standards and Technology 

NMI NASA Management Instruction

NPD NASA Policy Directive

NPR NASA Procedural Requirements

OIG Office of Inspector General

OMB Office of Management and Budget 

OSTP Office of Science and Technology Policy

PA&E Program Analysis and Evaluation

SI International System of Units
MARCH 29, 2010

REPORT NO. IG-10-011

OVERVIEW

REVIEW OF THE CONSTELLATION PROGRAM’S 

REQUEST TO DISCONTINUE USING THE 

METRIC SYSTEM OF MEASUREMENT

The Issue

The Office of Inspector General (OIG) examined the Constellation Program’s1 draft 

request to reverse its 2-year-old decision to implement the metric system (also known as 

the International System of Units or SI)2 as its standard system of measurement and 

instead use the U.S. customary system3

Results

(e.g., feet, pounds, ounces). Our objective was to

assess the basis for the Constellation Program’s request to NASA’s Chief Engineer for an 

exception to NASA’s policy that requires use of the metric system in Agency programs. 

In addition to examining this specific request, we considered the possible long-term 

impact on other NASA projects and the Agency’s efforts to expand use of the metric 

system if the exception was granted, which appears likely. Details of the review’s scope 

and methodology are in Appendix A.

We concluded that the Constellation Program’s request for an exception to using the 

metric system as its standard system of measurement does not clearly meet NASA 

criteria for granting such an exception. In addition, the request does not adequately 

consider the long-term impact of the decision on future NASA projects. 

Specifically, we found that the Program’s draft request for an exception to using the 

metric system does not meet the criteria for exceptions under NASA Policy Directive 

(NPD) 8010.2E “Use of the SI (Metric) System of Measurement in NASA Programs,” 

March 4, 2007 (see Appendix B). The request from Constellation Program officials 

suggests that implementing the metric system is impractical and its use could increase 

risk and threaten mission success. However, we found conflicting documentation 

attesting to the practicality of implementing the metric system as the primary system of 

 1 On February 1, 2010, the President released his proposed fiscal year (FY) 2011 budget for NASA. In 

that budget request, the President proposed cancelling the Constellation Program. While the focus of this 

audit is on the Constellation Program’s specific request for an exception to NASA’s policy requiring use 

of the metric system, the issues discussed in this audit affect other Agency programs and broader policy 

issues. 

2 International System of Units (abbreviated SI from the French le Système international d'unités) is the 

modern form of the metric system. The terms “metric” and “SI” are used interchangeably in this report.

3 The system is also known as the “English,” “British Standard,” and “British Imperial” system of 

measurement. 
OVERVIEW

ii REPORT No. IG-10-011

measurement in the Constellation Program. In addition, other Constellation Program

documentation we reviewed refutes the suggestion that implementing the metric system

would increase risk in this Program. We also found that neither the Constellation 

Program nor the NASA Chief Engineer has fully assessed the long-term impact on the 

Agency of moving away from use of the metric system. 

We also found that NASA’s written policy directing use of the metric system in Agency

programs is deficient in several respects. First, NPD 8010.2E does not define the term 

“adds unacceptable risk,” which leads to differing interpretations of the risks that 

programs can cite when seeking an exception to using the metric system. Second, the 

NPD does not provide a mechanism for exceptions to be reevaluated in the event new 

projects are added to an exempt program or improvements are made in the availability of 

metric-measured parts. A previous OIG report4

During our fieldwork, NASA’s Chief Engineer told the OIG that he planned to approve 

the Constellation Program’s request for an exception based on the additional costs 

required to implement the metric system, which Constellation Program officials 

estimated at $368 million. These implementation costs arise mainly from the reuse of 

hardware and software from previous NASA programs, including the Space Shuttle, that 

did not use the metric system, thus requiring revisions to engineering documents, test 

plans, test equipment, facilities, training, and operations. According to the Chief 

Engineer and Constellation Program management, the estimated $368 million for metric 

system implementation would be better spent on mitigating higher priority Program risks. 

recommended that approved exceptions

should not be “open-ended,” but rather reviewed approximately every 5 years to see if 

conditions underlying the rationale for the exception had changed. Although NASA 

management agreed with this recommendation and stated that the pertinent NPD would 

be modified to “require reassessment of opportunities and rejustification of program-wide 

waivers where still required, at least once every 5 years,” the current version of the NPD

does not contain this requirement. 

We found that because the Department of Defense (DoD) has not fully embraced the 

metric system as the manufacturing standard in its projects, and because of the size of its 

contracts, DoD exerts an overriding influence on the U.S. aerospace industry. NASA 

officials stated that until DoD begins converting its major programs to the metric system, 

NASA will not be able to easily transition to the metric system due to a lack of aerospace

parts designed in metric units. 

Management Action

We recommended that the NASA Chief Engineer, prior to granting exceptions to the 

requirement to use of the metric system in NASA programs, should ensure that a benefitcost analysis is conducted to determine the short- and long-term impact on the Agency of 

 4 NASA OIG. “Assessment of NASA’s Use of the Metric System” (Report No. G-00-021, February 20, 

2001).
OVERVIEW

REPORT NO. IG-10-011 iii

not implementing the metric system. In addition, the Chief Engineer should add 

clarifying language to NPD 8010.2E to more clearly define how the “adds unacceptable 

risk” criteria should be interpreted when evaluating whether to request an exception to 

metric system implementation. Further, the Chief Engineer should add language to NPD 

8010.2E requiring a review of approved exceptions every 5 years to ensure the exception 

remains applicable and justified. Lastly, the Chief Engineer should engage DoD and 

other interested Federal agencies to develop a strategy for broader implementation of the 

metric system within the aerospace industry. 

In response to the OIG’s draft report (February 19, 2010), the Chief Engineer stated that 

two NASA policy changes have occurred that directly apply to the recommendations.

First, the President’s FY 2011 Budget Request for NASA, if enacted, will cancel the 

Constellation Program; the Chief Engineer stated that he has, consequently, placed a hold 

on the Program’s request for a waiver [exception] from using U.S. customary units.

Second, on March 16, 2010, NASA cancelled NPD 8010.2E when it was superseded by 

NPD 7120.4D, “NASA Engineering and Program/ Project Management Policy,” which

includes a section addressing the “Metric System of Measurement.” The Chief Engineer 

noted that unlike NPD 8010.2E, the new NPD does not include the exception language 

“adds unacceptable risk.” Nevertheless, the Chief Engineer stated that he concurred with 

our recommendations; specifically, the Agency will clarify the requirement to conduct a 

rigorous evaluation, including a non-quantitative discussion of the costs and benefits, in 

future updates to the NPD; ensure that each new project will be evaluated for its ability to 

implement the metric system; and initiate an engagement activity with the DoD, Federal 

Aviation Administration, Aerospace Safety Advisory Panel, and others to develop a longterm metric system implementation strategy within the aerospace industry. 

Management’s planned actions to conduct a benefit-cost analysis and to engage DoD and 

other Federal agencies to develop a strategy for broader implementation of the metric 

system are responsive to our recommendations. However, we do not agree that NPD 

7120.4D adequately addresses our concerns in regard to revising NPD 8010.2E and

clearly defining exception criteria or ensuring that NASA policy complies with Federal 

law and Executive Orders. Therefore, we recommend that the Chief Engineer establish a 

NASA Procedural Requirements document to ensure that NASA program and project 

managers effectively implement the metric system policy stated in NPD 7120.4D to the 

fullest extent possible. We request additional comments from the Chief Engineer on this 

revised recommendation by April 16, 2010. 

MARCH 29, 2010

REPORT NO. IG-10-011 V

CONTENTS

INTRODUCTION

Background of Metric System Implementation ______________ 1

Objectives __________________________________________ 5

RESULTS

Constellation’s Request for an Exception Does Not Meet NASA 

Criteria; NASA’s Metric System Implementation Policy Is 

Deficient _________________________________________ 6

APPENDIX A

Scope and Methodology_______________________________ 19

Prior Coverage ______________________________________ 20

APPENDIX B

NPD 8010.2E “Use of the SI (Metric) System of Measurement in 

NASA Programs” __________________________________ 21

APPENDIX C

National Institute of Standards and Technology (NIST) 

Letter to NASA ___________________________________ 26

APPENDIX D

NASA’s Response to NIST _____________________________ 27

APPENDIX E

Management Comments ______________________________ 29

APPENDIX F

Report Distribution___________________________________ 33

MARCH 29, 2010

REPORT NO. IG-10-011 1

INTRODUCTION

Background of Metric System Implementation 

The U.S. customary5 system of measurement – based on the foot, pound, and fluid ounce

– is the most commonly used system of measurement in the United States. The 

International System of Units (SI)6

Figure 1. Map of the World Showing Usage of Systems of Measurement

or metric system of measurement – based on the 

decimal system – is the most commonly used system of measurement throughout most of 

the world. As shown in Figure 1, the metric system is the official system of measurement 

for all nations except the United States, Burma (Myanmar), and Liberia. Although 

legislation in 1988 designated the metric system as the “preferred system of weights and 

measures for United States trade and commerce” the legislation contained no deadline for 

its adoption.

Source: Wikipedia 

Red (or black) represents countries that have not adopted the metric system as their standard system of 

measurement.

Federal Laws and Regulations. The Metric Conversion Act of 1975 (Public Law 

94-168) declared a national policy of converting to the metric system and established the 

 5 The system is also known as the “English,” “British Standard,” and “British Imperial” system of 

measurement. 

6 International System of Units (abbreviated SI from the French le Système international d'unités) is the 

modern form of the metric system. The terms “metric” and “SI” are used interchangeably in this report.
INTRODUCTION

2 REPORT NO. IG-10-011

United States Metric Board to coordinate the voluntary transition, but did not include 

target dates for metric conversion. The Omnibus Trade and Competitiveness Act of 1988 

amended the 1975 Act and declared the metric system to be the “preferred system” of 

weights and measures for trade and commerce in the United States. The 1988 Act 

directed Federal agencies to convert to the metric system to the degree economically 

feasible by the end of fiscal year (FY) 1992. The Act does not include consequences for 

agencies that fail to convert to the metric system. 

In 1991, Executive Order (EO) 12770, “Metric Usage in Federal Government Programs,”

directed all Executive departments and Federal agencies, including the Department of 

Defense (DoD), to implement the metric system by the end of FY 1992 or by another 

date determined in consultation with the Secretary of Commerce. EO 12770 also directed 

agency heads to establish a process for reviewing proposed exceptions to metric system 

use. Agencies were also directed to list the exceptions granted in their annual report to 

the Department of Commerce along with recommendations for actions to increase the use 

of the metric system. The Federal Reports Elimination and Sunset Act of 1995 (Public 

Law 104-66) repealed the annual reporting requirement but did not repeal EO 12770. 

Similar to the 1988 Act, the EO does not include consequences for agencies that do not 

convert to the metric system. 

While these Federal laws and EOs did not require private companies to implement the 

metric system, many U.S. industrial sector companies and those in the auto industry have

successfully converted. For example, U.S.-based companies such as Caterpillar, IBM, 

General Motors, DuPont, Black and Decker, and John Deere have responded to world 

market economies and converted most of their products to the metric system. In addition, 

the U.S. scientific community extensively uses the metric system, and NASA’s work 

with its international partners on the International Space Station (ISS) is based almost 

entirely on the metric system. 

However, the U.S. aerospace industry, including companies such as The Boeing 

Company and Lockheed Martin Corporation, have not converted exclusively to the 

metric system because their largest customer, DoD, continues to base some of its new 

programs in U.S. customary units. For example, DoD’s Joint Strike Fighter is being 

fabricated using U.S. customary units. In contrast, in 2006 the Navy commissioned its 

first surface vessel to be fabricated in metric units, the Army Corp of Engineers uses the 

metric system for all new military construction projects, and virtually all DoD grant 

programs are administered in the metric system because the programs are in scientific 

and technical areas in which use of the metric system prevails. 

Evolution of the Metric System at NASA. In 1980, NASA issued NASA Management 

Instruction (NMI) 8010.2, “Use of the Metric System of Measurement in NASA 

Programs,” its first Agency-wide metric system implementation policy, and designated 

the Chief Engineer as the executive responsible for NASA’s metric policy. The NMI

required each new NASA program or project to thoroughly consider implementing the 

metric system as their standard system of measurement. After passage of the Omnibus 
INTRODUCTION

REPORT NO. IG-10-011 3

Trade and Competitiveness Act of 1988, NASA engaged in an Agency-wide effort to 

convert to the metric system. 

In the early 1990s, NASA Centers developed metric transition plans, purchased metric 

measurement equipment and machine tools, and provided employees training in use of 

the metric system. NASA also began to assess requirements for space-quality parts 

fabricated in metric units and developed qualifications for commonly used parts such as 

threaded fasteners and fluid fittings. 

In 1991, NASA published NMI 8010.2A, which identified the metric system as the 

“preferred” system of weights and measures for the Agency. NMI 8010.2A required new 

projects and programs to use the metric system unless NASA’s Chief Engineer granted

an exception and further stated that by the end of FY 1992 the Agency would use the 

metric system to the extent economically feasible in procurements, grants, and businessrelated activities. 

As mentioned previously, the Federal Reports Elimination and Sunset Act of 1995 

repealed the requirement for each Federal agency to submit an annual progress report to 

the Department of Commerce on metric system implementation. In March 2004, in its 

last report to the Department of Commerce, NASA stated that the Agency had 

“substantially achieved the maximum level of SI use that is practical at this time.”

NASA’s report explained that it continued to use the U.S. customary system because 

“. . . lack of American aerospace industry commitment to the SI system remains as a 

major impediment to substantially increased use of SI at this time in NASA Programs.” 

Previous Office of Inspector General (OIG) Work on NASA’s Use of the Metric 

System. In a 2001 report,

7

We made eight recommendations in our 2001 report intended to improve the use of the 

metric system within NASA. Among them were recommendations to reexamine the 

Agency’s efforts to convert to the metric system, develop a new approach for converting 

to the metric system, closely monitor technical interfaces between metric and U.S.

customary units, reinvigorate and document the metric system exception process, and use 

the metric system as the preferred system for interactions with the public. 

we found that NASA had provided managers with minimal 

guidance for using the metric system and that NASA’s use of the metric system varied

from program to program and from Center to Center. In addition, we found that the 

Agency had not documented its metric system exception process for several years. 

NASA management concurred with seven of the eight recommendations. The one 

recommendation with which NASA did not concur was a suggestion that Agency 

“program and functional offices should use SI as the preferred system for interactions 

with the external community in public events, educational materials, and Web site 

 7 NASA OIG. “Assessment of NASA’s Use of the Metric System” (Report No. G-00-021, February 20, 

2001).
INTRODUCTION

4 REPORT NO. IG-10-011

viewing.” Instead, NASA management said it planned to use its education initiatives to 

further increase the public’s use and knowledge of the metric system.

Of the seven recommendations NASA concurred with, one was not implemented. This 

recommendation cautioned against granting exceptions to entire programs and, if an

exception was granted, that it not to be open-ended but rather reviewed approximately

every 5 years for continuing validity. We make a similar recommendation in this review. 

Evolution of Metric System Use for the Constellation Program. In a March 2006

study, NASA’s Office of Program Analysis and Evaluation (PA&E) addressed the “Use 

of SI Units for Future NASA Programs.” The study was part of the larger process to 

select measurement units for the Constellation Program. The study stated that, “among 

U.S. space organizations,

8

In October 2006, at the 57th Annual International Astronautical Congress, the NASA 

Administrator stated that 

NASA is in the forefront of converting to SI. NASA’s choice 

appears to be either to continue leading or to follow.”

[i]t is important that the engineering standard for NASA architecture be specified with 

the international metric, or SI, standard as the base unit of measure, with the English 

units only by exception when it makes sense for NASA to do so. Thus, we hope for a 

high degree of compatibility of interfaces and standard as space faring nations explore 

the Moon, Mars, and near Earth asteroids together.

NASA Policy Directive (NPD) 8010.2E, “Use of the SI (Metric) System of Measurement 

in NASA Programs,” March 4, 2007, describes NASA’s policy of adopting the metric 

system as the preferred system of measurement. The policy requires the use of the metric 

system in all new programs and projects covered by NASA Procedural Requirements 

(NPR) 7120.5D, “NASA Space Flight Program and Project Management Requirements,”

March 6, 2007. However, NPD 8010.2E provides a process for programs or projects to

seek an exception from the Chief Engineer on use of the metric system. According to the 

policy, exceptions may be granted “where use of SI is demonstrated to be impractical, 

adds unacceptable risk, or is likely to cause significant inefficiencies or loss of markets to

U.S. firms.”

To comply with NPD 8010.2E, the Constellation Program issued Management Directive 

030, “Use of SI as the Primary System of Measure for the Constellation Program, 

Projects, Systems and Mission” in December 2007. The Directive established the metric 

system “as the standard and default unit of measure of and throughout the Constellation 

Program.” It further states that “A consistent practice of units throughout the 

Constellation Program life cycle is critical to mission success” and stipulates why the 

Program should implement the metric system: 

• U.S. Federal law directs use of SI;

 8 Organizations benchmarked included Space and Missile Systems Center (SMC), National 

Reconnaissance Office (NRO), Missile Defense Agency (MDA), and National Oceanic and Atmospheric 

Agency (NOAA)
INTRODUCTION

REPORT NO. IG-10-011 5

• NASA policy directs use of SI;

• SI is simpler and less error prone;

• Consolidation across NASA Science and Engineering practices;

• Alignment with NASA’s international space partners;

• Increased international competitiveness of the U.S. space industry; and

• Consistency with U.S. education and skills of next generation space workers.

The Directive allowed exceptions where mixed use of U.S. customary and metric units 

could be continued for legacy hardware, engineering, or fabrication. However, the 

Directive established the Constellation Program as a leader in the transition of NASA and 

U.S. aerospace companies from U.S. customary to metric units of measure.

NASA’s basic approach was to manage the Constellation Program in metric units, but 

grant exceptions to certain disciplines steeped in legacy tools, processes, and 

methodologies based on U.S. customary or a mixture of measurement systems. The 

Program approved the use of U.S. customary units of measure for several legacy 

hardware components and designs (as well as associated tooling and infrastructure) and 

allowed users the option to justify the primary use of U.S. customary units with 

additional safeguards in place to reduce technical risk. This philosophy of leaving legacy 

hardware in the measurement units in which it was originally built has been used 

extensively in many industries that have made the successful transition to the metric 

system. 

Objectives

The OIG reviewed the Constellation Program’s draft request to reverse its 2-year-old 

decision to implement the metric system as its standard system of measurement and, 

instead, continue to use the U.S. customary system as the primary and default system of 

measure. Our objective was to assess the basis for the request and to consider the 

possible long-term impact on the Agency if the request was granted, which appears 

likely. See Appendix A for details of the review’s scope and methodology and a list of 

prior audit coverage. 
RESULTS

6 REPORT NO. IG-10-011

CONSTELLATION’S REQUEST FOR 

AN EXCEPTION DOES NOT 

MEET NASA CRITERIA;

NASA’S METRIC SYSTEM 

IMPLEMENTATION POLICY 

IS DEFICIENT

The Constellation Program’s draft request for an exception to permit the use of U.S. 

customary system of measurement instead of the metric system does not meet NASA 

policy requirements for granting an exception. Moreover, the request and the process for 

granting approval do not consider the long-term impact of an exception on future Agency 

programs. In addition, NASA’s metric system implementation policy, NPD 8010.2E,

does not define the phrase “adds unacceptable risk,” thereby leaving the criteria open to 

wide-ranging and inconsistent interpretations. Further, the NPD does not provide a 

mechanism for exceptions to be reevaluated in the event new projects are added to an 

exempted program or improvements are made in the availability of metric parts. Several 

of these issues have Agency-wide impact far beyond the Constellation Program. 

The Constellation Program’s Reversal of its Decision to Use SI

The Constellation Program began formally assessing the cost of implementing the metric 

system within the Program’s various projects by developing detailed implementation 

plans after the release of Management Directive 030 in December 2007. By October 

2008, initial cost estimates for implementing the metric system in the Constellation 

Program totaled $368 million over a 7 year-period, as depicted in Figure 2. 
RESULTS

REPORT NO. IG-10-011 7

Source: Constellation Program

Specifically, individual project costs were estimated at $67 million for Orion,

$231 million for Ares I, and $70 million for Constellation Ground Operations. NASA 

officials attributed these costs to the reuse of hardware and software designs from 

previous flight programs that used U.S. customary units, thus requiring revisions to 

documentation and interface drawings. Of significant concern to Constellation Program 

officials was that more than 50 percent of this cost – almost $200 million – was occurring 

in FYs 2009 and 2010 when their budget was constrained due to operational costs for the 

Space Shuttle and ISS programs. 

In 2008, Constellation began to experience design and technical issues unrelated to 

metric use to the extent that the Program’s overall schedule was projected to be delayed 

by up to 18 months and the Program would require significant additional funding. 

Consequently, the Constellation Program Manager took steps to improve the possibility

of meeting the Program’s baseline schedule of March 2015 by identifying potential 

deletions, modification, or simplifications of the Program’s technical requirements in 

order to save time and money. One of the items proposed and subsequently approved at 

the Program level was to reverse its earlier decision to implement the metric system. 

In August 2009, the Constellation Program Systems Engineering Control Board approved 

Change Request 000390, “Direct Implementation for Use of a Hybrid System of Units 

and U.S. Customary (in-pound) System as the Primary System of Measure for the 

Constellation Program, Projects, System and Missions,” August 6, 2009, which rescinded 

Management Directive 030 and established use of a hybrid system of U.S. customary 

units with limited use of metric units in Constellation. According to the Change Request, 

Program management “looked at various implementation strategies and worked the 

2009 2010 2011 2012 2013 2014 2015

Crew Exploration Vehicle 

(Orion) $20 $26 $12 $8 $1 

Crew Launch Vehicle (Ares I) $49 $82 $47 $20 $16 $13 $4 

Ground Operations $5 $5 $35 $25 

$-

$20 

$40 

$60 

$80 

$100 

$120 

$ millions

Figure 2. Constellation Program's Estimated Costs to 

Implement the Metric System, per Fiscal Year (October 2008)
RESULTS

8 REPORT NO. IG-10-011

implementation details to the point of having workable implementation plans [for using 

the metric system] in all projects. However, the cost estimates to achieve these plans 

significantly exceeded the resources that could be made available in the critical years.” 

NASA’s Chief Engineer is required to provide final approval before the exception to the 

requirement that all new NASA programs use the metric system takes effect. In 

conversations with the OIG, the Chief Engineer indicated that he planned to approve the 

Constellation Program’s request for an exception.

Office of Management and Budget (OMB) Recommended Analyses 

OMB Circular No. A-94, “Guidelines and Discount Rates for Benefit-Cost Analysis of 

Federal Programs,” October 29, 1992, recommends that benefit-cost and costeffectiveness analyses be used as management tools when considering changes in 

Government programs or projects. The Circular defines a benefit-cost analysis as

A systematic quantitative method of assessing the desirability of government projects 

or policies when it is important to take a long view of future effects and a broad view 

of possible side-effects.

The Circular also states that 

A program is cost-effective if, on the basis of life cycle cost analysis of competing 

alternatives, it is determined to have the lowest costs expressed in present value terms 

for a given amount of benefits. Cost effectiveness analysis is appropriate whenever it 

is unnecessary or impractical to consider the dollar value of the benefits provided by 

the alternatives under consideration.

The Circular recommends use of these analyses to help meet the goal of promoting 

efficient resource allocation through well-informed decision making. The Circular 

describes four elements of the analyses: policy rationale, explicit assumptions, 

evaluation of alternatives, and benefit-cost verification. Agency officials did not conduct 

any of these analyses when deciding to request an exception to use of the metric system 

in the Constellation Program. Rather, it appears their decision was based exclusively on 

the estimated cost and timetable for implementing metric measurements in the Program. 

Moving forward, we believe that NASA management could enhance its decision making 

process by using the four elements in OMB Circular A-94 to analyze the issue of whether 

to implement the metric system in any of its programs or projects. 

Basis for Chief Engineer’s Approval of an Exception 

NPD 8010.2E allows the Chief Engineer to approve exceptions to implement the metric 

system in NASA programs. The criteria requires the Program seeking the exception to 

demonstrate that use of the metric system (1) is impractical, (2) adds unacceptable risk, or 

(3) is likely to cause significant inefficiencies or loss of markets to U.S. firms. The NPD 

also states that “special emphasis shall be placed on maximum use of SI units in 

cooperative programs with international partners.” We analyzed each of these criteria as 

they relate to the Constellation Program’s request for an exception.
RESULTS

REPORT NO. IG-10-011 9

Impractical. The NPD defines conversion to metric units as impractical if the 

conversion “is demonstrated to result in substantial increases in cost or unacceptable 

delays in schedule to obtain SI components.” It is difficult for us to assess whether 

implementation of the metric system would result in a substantial increase in cost because 

Constellation Program management did not conduct a life-cycle cost analysis. While 

Program management estimated that the cost of implementing the metric system for 

Constellation was $368 million, they did not evaluate the costs of not implementing the 

metric system over the life of the program. Furthermore, cost discussions have centered 

on FYs 2009 and 2010, although NASA was projected to spend approximately 

$97 billion on the Constellation Program through 2020. To make a fully informed 

decision, we believe NASA needs to assess the long-term costs of not implementing the 

metric system, because such costs may not be apparent for decades if NASA approves the 

exception and subsequently decides to include international participation later in the 

Constellation Program.

Beyond the specific exception requested by Constellation managers, NASA needs to 

assess the long-term impacts compared to potential short-term costs when deciding 

whether or not to use the metric system in other new NASA projects.

Adds Unacceptable Risk. The “adds unacceptable risk” language does not originate in 

Federal law or Executive Order, but rather was added as exception criteria by NASA in 

2004 when NPD 8010.2 was updated. The Constellation Program Manager and the Chief 

Engineer told the OIG that this criterion applies to the risk (acceptable or unacceptable) 

of expending resources on implementing the metric system in a new program versus 

spending those same resources to mitigate other identified risks in the program. 

The Constellation Program’s Management Directive 030, issued December 2007, 

established the metric system as the standard system of measure and stated that use of the 

metric system was simpler, less error prone, and aligned with NASA’s international space 

partners. Therefore, we question the validity of the Constellation Program’s request for 

an exception only 2 years later on the basis that use of the metric system “adds 

unacceptable risk” to the Program. 

The Mars Climate Orbiter mishap (discussed below) highlights the risks of working with 

and converting between the two systems of measurement and having to closely monitor 

components built using both metric and U.S. customary units of measure. Granting the 

Constellation Program an exception from using the metric system could introduce longterm risks related to use of components built in U.S. customary units and components 

built in metric units. The long-term risks increase if the Constellation Program involves 

international partners in later years – partners who, to a country, use the metric system. 

We recognize that the Constellation Program is using some legacy hardware built in U.S. 

customary units; however, the Program can minimize that risk by limiting use of that 

hardware and building new components fabricated in the metric system.

The Chief Engineer and Constellation Program management said they believe that the 

estimated $368 million for metric system implementation would be better spent on 
RESULTS

10 REPORT NO. IG-10-011

mitigating higher priority Program risks and therefore the Constellation Program’s 

request for an exception meets the intent of the NPD “adds unacceptable risk” criteria. 

However, before waiving the requirement to use the metric system, NASA should 

conduct an adequate life-cycle analysis to determine whether the possible savings 

identified as a result of not implementing the metric system could ultimately cost NASA

more in the long-term, either in the Constellation Program or its other scientific or 

exploration initiatives, many of which involve international partners or U.S. businesses

that have made the conversion to the metric system. 

Because the definition of “adds unacceptable risk” in NPD 8010.2E lacks specificity, a 

decision by NASA to grant the Constellation Program’s request for an exception could be 

defended as fitting squarely within the criteria. However, the interpretation offered by 

Constellation Program managers and the Chief Engineer is premised on the notion that 

the “risk” of spending funds to implement the metric system can always be deemed 

“unacceptable” in any budget- or schedule-constrained program in which, from the 

program managers’ perspectives, it would be advantageous to use the funds to address 

other program areas. However, such an interpretation of the risk criteria can lead to 

decisions that while seemingly sensible in the short term (in that funds originally 

designated for metric conversion can be applied to other high-priority issues), may not 

fully consider the longer-term impact on the specific program or broader Agency-wide 

interests. Moreover, given such a flexible interpretation of NASA policy, exceptions to 

the requirement to use the metric system have become the rule. In fact, NASA’s Chief 

Engineer said he could not recall one denial of the numerous requests for exceptions to 

the requirement to use the metric system. Such historic flexibility in applying the criteria 

calls into question NASA’s commitment to implementing the metric system in Agency 

programs and projects to the fullest extent possible.

Significant Inefficiencies or Loss of Markets. Although the Constellation Program did 

not cite this as exception criteria in their draft request, another exception included in 

NASA policy relates to whether use of the metric system is “likely to cause significant 

inefficiencies or loss of market to U.S. firms.” This criteria was established in the 

Omnibus Trade and Competitiveness Act of 1988 (Omnibus Act) to help alleviate 

concerns of U.S. industries who argued that they might lose market share in the United 

States if they were forced to produce in metric units while foreign firms fabricated 

products in U.S. customary units. Twenty-two years later, this concern is generally no 

longer valid since almost all foreign firms fabricate their parts in metric units. 

Support for Use of the Metric System in NASA Programs

Failure of Mars Climate Orbiter. In 1999, the Mars Climate Orbiter failed to enter 

orbit around Mars because of miscalculations resulting from its attitude-control system 

using U.S. customary units but its navigation software using metric units. 

The following year, OIG initiated a review of the Agency’s use of the metric system. 

Our February 20, 2001, report, “Assessment of NASA’s Use of the Metric [SI] System” 
RESULTS

REPORT NO. IG-10-011 11

(G-00-021), found that use of the metric system was inconsistent across the Agency. The 

Chief Engineer concurred with seven of the eight recommendations we made in our 2001 

report to improve the use of metric system within NASA in accordance with national 

policy and Agency guidance. One of our recommendations urged NASA to move 

cautiously when considering exempting entire programs from using the metric system:

Recommendation 6: NASA should be cautious in granting SI waivers to entire 

programs. Some programs which, viewed as a whole, could legitimately waive use of 

SI may contain projects that might best be conducted using SI. If a program is 

granted an SI waiver, use of SI within the program should be permitted where 

appropriate. Any program waivers granted should not be open-ended, but should be 

reviewed after approximately 5 years.

NASA agreed with this recommendation, and in their official response said it would 

modify NPD 8010.2C to require a review of any waivers at least once every 5 years.

However, interim revisions of the NPD did not include a requirement for additional 

reviews and the current version of this NPD (8010.2E) does not require a subsequent 

review of exceptions previously granted to NASA programs or projects. 

NASA Program Analysis and Evaluation Study. The 2006 PA&E study, “Use of SI 

Units for Future NASA Programs,” analyzed the selection of measurement units for the 

Constellation Program. The study found that parts fabricated in metric units were readily 

available from U.S. sources with little cost difference compared to parts built in U.S. 

customary units. The study stated that risks would exist in a program that maintains the 

use of U.S. customary units while the economy continues its transition to the metric 

system. While the study did not estimate the cost of transitioning to the metric system, 

PA&E officials concluded and Constellation Program managers agreed that the 

Constellation Program should use the metric system.

As discussed previously, NASA’s international partners and most scientific organizations 

around the world use the metric system. While the Constellation Program does not 

presently have international participation, the Augustine Committee’s

9

Finally, the President’s FY 2011 budget released in early February envisions significantly 

expanded international cooperation, and all of NASA’s international partners use the 

“Review of the

U.S. Human Space Flight Plans” issued in September 2009 states more broadly that 

“Actively engaging international partners in a manner adapted to today’s multi-polar 

world could strengthen geopolitical relationships, leverage global resources, and enhance

the exploration enterprise.” In addition, NASA’s Associate Administrator for 

Exploration Systems Mission Directorate said that several planned elements of the 

Constellation Program such as the Lunar Lander and Lunar Surface Systems will include 

the involvement of the international community. 

 9 In May 2009, NASA chartered the Augustine Committee to identify the best options for the nation to 

pursue for the future of human space flight. The Committee, supported by PA&E, reports to the NASA 

Administrator and the Director of the Office of Science and Technology Policy (OSTP), Executive 

Office of the President. 
RESULTS

12 REPORT NO. IG-10-011

metric system of measurement. NASA’s plans to increase cooperation with international 

partners in future initiatives should merit close consideration during reviews of all 

requests for an exception to using the metric system. 

Impact of the Constellation Program Decision on the Agency 

When considering individual exception requests, NASA should consider the impact of its 

decision on Agency-wide operations. NPD 8010.2E states that “NASA shall encourage 

and accommodate increasing the use of SI system of measurement as support capabilities 

expand, shall acquire capabilities to support that goal wherever practical, and shall 

cooperate with the private and public sectors to overcome barriers to use and increase 

understanding of the SI system of measurement.” The Chief Engineer has previously 

approved exceptions for programs or projects because NASA management determined 

that metric system implementation costs were impractical or that funds could be used in a 

more tangible way to fix a known risk. 

Although the projected costs for implementing the metric system in various Agency 

programs initially may appear high, NASA should consider the full life-cycle cost

benefits prior to granting an exception. Such long-range considerations were not 

evaluated for previously granted exceptions. The Chief Engineer stated that calculating 

long-term benefits for the Constellation Program request was of little value in light of 

insufficient funding in the near term to implement the metric system. We recommend 

that the Chief Engineer not view exception requests as an “all or nothing” decision. One 

option would be for NASA to distinguish between projects within programs, authorize an 

exception to the metric system if warranted, but press forward with metric system 

conversion on other aspects of the program to move the Agency closer to realizing the 

goals of NPD 8010.2E, the Omnibus Act, and EO 12770. 

Impact of the Constellation Program Decision on Metric System

Implementation in the United States

The National Institute of Standards and Technology (NIST) directs and coordinates 

Federal efforts to implement the metric system in Government agencies and establish the 

metric system as the preferred system of weights and measures for U.S. trade and 

commerce. In response to the Constellation Program’s decision not to use the metric 

system, NIST’s Metric Coordinator in the Weights and Measures Division stated on June 

10, 2009: 

Prolonging the transition to the SI will continue to increase the long term costs to the 

agency, especially for a project that will establish a long lived physical infrastructure 

on the lunar surface. NASA’s original plans to use SI measurements on the moon 

would have immediately brought SI into greater use among thousands of engineers 

and other technical staff within the agency and its contractors as launch vehicles and 

other lunar projects were designed and constructed. The initial decision by NASA 

management would have pulled the SI into greater use in the domestic aerospace 

industry, not to mention the long term impact of increased SI use in the U.S. economy 
RESULTS

REPORT NO. IG-10-011 13

resulting from new technological developments from NASA research and other spinoffs.

In addition, on October 16, 2009, the Deputy Director of NIST sent a letter to the NASA 

Administrator (see Appendix C) “to support and emphasize the importance of [NASA’s] 

decision to implement an agency metric policy for Constellation Program operations 

when the United States returns to the moon.” The Deputy Director stated that “[t]he 

successful voluntary U.S. transition to the metric system is a critical factor in the 

competitive success of companies and the country. NASA is a flagship federal agency to 

which other agencies and industry look for leadership and inspiration.”

NASA’s response to NIST on November 10, 2009 (see Appendix D), while stating that 

limited funds forced NASA to discontinue use of metric units for the Constellation 

Program, held out hope for the future: 

New elements (e.g. Lunar Lander and Lunar Surface Systems), not relying on heritage 

systems, are still in the early requirements and operations concept development stage. 

These projects will have the most involvement with the International community. NASA 

expects to utilize SI based systems for beyond Low-Earth-Orbit in the coming years.

The DoD Influence 

In its last progress report to the Department of Commerce in March 2004, NASA stated 

that the Agency had “substantially achieved the maximum level of SI use that is practical 

at this time.” NASA explained that “. . . lack of American aerospace industry 

commitment to the SI system remains as a major impediment to substantially increased 

use of SI at this time in NASA Programs.”

During this review, NASA officials repeatedly expressed the opinion that until DoD, the 

dominant entity in the U.S. aerospace industry, completely embraces the metric system, 

NASA would not be able to noticeably influence the industry’s transition on its own. We 

note that DoD and other Federal agencies have made efforts to implement the metric 

system in certain programs. For example, the amphibious transport dock, USS San 

Antonio (LPD 17), built by Northrop Grumman Ship Systems and commissioned in 

January 2006, is the first Navy ship to be designed in metric measurements. In addition, 

Lockheed Martin, the prime contractor for the Constellation Program, entered into a 

contract with the National Reconnaissance Office10 in 2007 that requires “all supplies, 

components, reports, documentation, or services designed, fabricated, assembled, 

delivered or performed . . . to utilize the Metric System of Measurement.” However, 

other major programs such as DoD’s Joint Strike Fighter, estimated to cost more than 

$300 billion,11

 10 Lockheed Martin. Prime Flowdowns for NRO 000-07-C-0107, ACE (ATC076, 2/19/07 

continue to be designed and manufactured in U.S. customary units. 

http://www.lockheedmartin.com/suppliers/bu_info/space/site_7742/atc_flowdown/ATC076_2-19-07.doc

(accessed January 29, 2010). 

11 Government Accountability Office. “Joint Strike Fighter: Strong Risk Management Essential as Program 

Enters Most Challenging Phase” (GAO-09-711T, May 20, 2009).
RESULTS

14 REPORT NO. IG-10-011

Conclusion

In our February 2001 report, “Assessment of NASA’s Use of the Metric [SI] System,” we 

stated that 

[b]y law and policy, SI is the preferred system of measurement within NASA. As the 

United States continues its slow transition to the metric system, NASA must decide 

whether it wants to be a leader or a follower in the transition process. Both roles 

come with a cost. If NASA chooses to push forward with the Agency’s use of the 

metric system, near term costs may increase and short-term risk (both to schedule and 

mission success) may rise to some degree. However, if the Agency follows the 

aerospace industry’s slow transition to SI, the protracted period during which NASA 

uses mixed metric and English systems may further increase costs and risks for 

NASA programs.

NASA is the nation’s most visible science and technology agency, and is involved in 

highly publicized cooperative projects with a world that almost exclusively uses the 

metric system. Certainly an argument could be made that as the nation’s symbol of 

technological prowess, NASA has a role in promoting acceptance and use of the 

metric system. We believe the Agency should reassess its conversion to the metric 

system and determine the most appropriate approach for the Agency to successfully 

transition to SI.

These words are as applicable today as they were in 2001. Almost 10 years since 

issuance of that OIG report, NASA’s Chief Engineer has approved every request for an 

exception to using the metric system in Agency programs. Moreover, NASA’s criteria to 

evaluate requests for exceptions to using the metric system remains ambiguous and lacks

appropriate specificity. 

The Constellation Program’s Management Directive 030, issued in December 2007, 

established sound reasons for implementing the metric system; prime among them was 

that the metric system is simpler, less error prone, and aligns with NASA’s international 

partners. We understand that NASA will not fully realize the value of the metric system 

of measurement until this standard is universally adopted by the U.S. aerospace industry. 

We also understand that if the major entities in the aerospace and defense industries are 

not moving consistently toward metric system usage, no Federal agency apart from DoD 

likely will be able to significantly accelerate the transition. However, NASA has the 

opportunity, in the words of the OIG’s 2001 report, to decide “whether it wants to be a 

leader or a follower in the [SI] transition process.” 

Finally, while we believe that Constellation’s draft request does not meet NASA policy 

criteria for granting an exception, we urge the Chief Engineer in this and other cases to 

consider the long-term impacts of any decision to waive implementing the metric system. 

In addition, while NPD 8010.2E does not require NASA to re-examine previously 

approved exceptions to implementing the metric system, we believe NASA may be 

missing significant opportunities to implement the metric system in discrete projects 

because of an exception previously granted to the overall program. 
RESULTS

REPORT NO. IG-10-011 15

Management’s Comments on the Report and Evaluation of 

Management’s Comments

The Chief Engineer provided comments in response to our February 19, 2010, draft 

report (see Appendix E for the full text of management’s comments). Although we 

carefully considered these comments in preparing this final report, we did not make a 

series of requested changes as described below:

Management’s Comments on the Report. The Chief Engineer stated that since the 

issuance of the OIG’s draft report, two NASA policy changes have occurred that directly 

apply to the recommendations. First, the President’s FY 2011 Budget Request for 

NASA, if enacted, will cancel the Constellation Program and all its projects. Second, on 

March 16, 2010, NASA cancelled NPD 8010.2E when it was superseded by NPD 

7120.4D, “NASA Engineering and Program/ Project Management Policy,” which 

includes a section addressing the “Metric System of Measurement.” 

The Chief Engineer stated that because of the potential cancellation of the Constellation 

Program, he has placed a hold on the Program’s request for a waiver [exception] from 

using U.S. customary units. In addition, the Chief Engineer requested deletion of several 

references in the report regarding long-term risks of engaging international partners if 

Constellation does not adopt an SI strategy. The Chief Engineer said he believes those 

issues have been adequately mitigated and should be removed from the report since it is 

the intent of NASA to utilize SI units on vehicle projects that have lunar content. The 

Chief Engineer stated that the Constellation Program waiver [exception] was intended for 

the Low Earth Orbit projects, not for projects intended for beyond Low Earth Orbit. 

Evaluation of Management’s Comments. The Chief Engineer stated in his response to 

the draft report that NASA will use the metric system on vehicle projects that have lunar 

content and involve international participation. NASA made the same comments in its 

response to the NIST Deputy Director (Appendix D). However, the Constellation 

Program’s Change Request does not support the position that NASA will use the metric 

system when developing future lunar vehicles. As discussed earlier, Change Request 

000390, as well as the draft exception request sent to the Chief Engineer, states that the 

decision to use U.S. customary units “applies to all constituents and aspects of the CxP 

[Constellation Program], including organizations, personnel, missions, systems, products, 

processes, plans, operations, communications, data, documents, hardware, software, 

contracts, contractors, vendors, and deliverables.” 

Furthermore, in the change request approved by the Constellation Program Systems 

Engineering Control Board, the following statements appear: 

• The Orion/Ares I stack for ISS and lunar missions will be managed solely in U.S. 

Customary. 

• The Ares V vehicle will be managed solely in U.S. Customary.
RESULTS

16 REPORT NO. IG-10-011

• For the Altair vehicle the units of development and operations will be decided . . .

no later than PDR [Preliminary Design Review] or initiation of procurement 

contracts, whichever occurs first.

• For lunar surface systems provide by the United States, the units of development 

and operations will be decided . . . no later than PDR or initiation of procurement 

contracts, whichever occurs first.

• For lunar surface operations the environment is expected to be mixed units

(similar to the ISS Program).

We could find no language in Constellation Program documents that reflects the Chief 

Engineer’s statement that NASA intends to use the metric system for lunar projects. 

Recommendations, Management’s Response, and Evaluation of 

Management’s Response

Recommendation 1. The Chief Engineer should, prior to granting a program or project 

an exception to NPD 8010.2E, consider the results of an OMB Circular A-94 type 

analysis to determine the benefit-cost impact to the program, project, and Agency of not 

implementing the metric system.

Management’s Response. NASA’s Chief Engineer concurred with the intent of the

recommendation. The Chief Engineer stated that the requirement for a benefit-cost 

evaluation will be added to future NPD updates, though the Chief Engineer stated that 

“OMB Circular A-94 type analysis is problematic at best and the NPD language will 

allow for a non-quantitative discussion of cost benefit.” The estimated completion date 

for revising the NPD is December 31, 2010. 

Evaluation of Management’s Response. Management’s proposed actions are 

responsive. Because NASA cancelled NPD 8010.2E, the recommendation will be closed 

upon verification that the requirement to conduct a benefit-cost analysis has been added 

to appropriate NASA policy.

Recommendation 2. The Chief Engineer should revise NPD 8010.2E to

a. adequately define the “Adds Unacceptable Risk” exception criteria and

b. require individual projects added to complex or long-term programs to 

periodically re-evaluate their ability to implement the metric system.

Management’s Response. The Chief Engineer stated that on March 16, 2010, NASA 

cancelled NPD 8010.2E when it was superseded by language added to NPD 7120.4D, 

“NASA Engineering and Program/Project Management Policy.” The Chief Engineer 

said because NPD 7120.4D does not include the language “adds unacceptable risk.” he 

considers the recommendation to define the exception criteria no longer valid. 

Management concurred with the second part of the recommendation to periodically reevaluate new projects added to ongoing programs to assess their ability to implement the 
RESULTS

REPORT NO. IG-10-011 17

metric system. The estimated completion date for implementing this latter 

recommendation is the onset of the next Agency project. 

Evaluation of Management’s Response. Management’s proposed actions are not

responsive to the intent of the recommendation. We believe that the language concerning 

metric system implementation in NPD 7120.4D does not adequately meet the intent of 

Federal Law and Executive Orders. NPD 7120.4D states: 

1. POLICY (i). Metric System of Measurement. It is NASA policy for all new 

programs and projects subject to NPR 7120.5 [“NASA Space Flight Program and 

Project Management Requirements”] to use the International System of Units 

(commonly known as the Systeme Internationale (SI) or metric system of 

measurement) for design, development, and operations; in preference to 

customary U.S. measurement units, for all internal activities, related NASA 

procurements, grants, and business activities. Exceptions to this policy may be 

granted by the NASA Chief Engineer based on program/project 

recommendations by the responsible Mission Directorate Associate 

Administrator. 

5. RESPONSIBILITY (j). Managers and engineers responsible for the 

realization of a program, project, service, or activity shall: 

...(9) If subject to NPR 7120.5, identify method for implementing the SI 

system of measurement prior to completion of the Systems Requirements 

Review or equivalent milestone during new Program/Project 

Formulation. Document approved deviations and waivers. 

(10) Document determinations on where and how the SI system of 

measurement is to be used in the Program or Project Plan, including use 

of SI units in related mission support and institutional projects. 

The intent of the first part of our recommendation was to have NASA more clearly define 

the parameters for an exception to Federal Law and Executive Orders to implement the 

metric system. NPD 7120.4D does not identify criteria for granting exceptions to using 

the metric system. The intent of part b of the recommendation was to ensure that blanket

exceptions were not granted to large programs when smaller projects within that Program 

could logically implement the metric system. Although NPD 7120.4D states that

exceptions should be documented, it does not state where, how, or who keeps the record, 

or for how long the exception lasts. NASA officials stated in both their response to the 

NIST Deputy Director (Appendix D) and in their response to the draft IG report 

(Appendix E) that the metric system will be implemented on vehicle projects that have 

lunar content since these are the projects in which international participation will most 

probably be involved. Moreover, NPD 8010.2E stated that “[s]pecial emphasis shall be 

placed on maximum use of SI [metric] units in cooperative programs with international 

partners.” However, this language does not appear in the recently approved version of 

NPD 7120.4D. Thus, with NPD 8010.2E cancelled, the requirement to apply special 
RESULTS

18 REPORT NO. IG-10-011

emphasis to implement the metric system in programs with international participation no 

longer appears in any NASA policy documents. 

Consequently, we recommend that the Chief Engineer create an NPR based on the 

relevant language in NPD 8010.2E and the recommendations contained in this report. 

While NPDs are policy statements that describe what is required by NASA management 

to achieve its vision, mission, and external mandates and who is responsible for carrying 

out those requirements, NPRs provide Agency requirements to implement NASA policy

as delineated in an associated NPD. We request that the Chief Engineer provide 

additional comments on Recommendation 2 in response to this final report by April 16, 

2010.

Recommendation 3. The Chief Engineer should engage DoD and other Federal 

agencies to develop a strategy for the long-term implementation of the metric system 

within the aerospace industry.

Management’s Response. NASA’s Chief Engineer concurred with the 

recommendation. The Chief Engineer stated that he will engage DoD, Federal Aviation 

Administration, Aerospace Safety Advisory Panel, and other relevant Federal agencies 

and interested commercial aerospace parties in an effort to develop a long-term metric 

system implementation strategy within the aerospace industry. The Chief Engineer said 

NASA plans to staff an Industrial Base Liaison by October 2010 to lead this task. 

Evaluation of Management’s Response. Management’s proposed actions are 

responsive and the recommendation will be closed following verification of the 

corrective action.
APPENDIXES

REPORT NO. IG-10-011 19

APPENDIX A

Scope and Methodology

We performed this review from September 2009 through February 2010 in accordance 

with generally accepted government auditing standards. We limited our review of 

internal controls to NASA’s metric system policy and the granting of exceptions. Those 

standards require that we plan and perform our work to obtain sufficient, appropriate 

evidence to provide a reasonable basis for our findings and conclusions based on the 

objectives. We believe that the evidence obtained during this review provides a 

reasonable basis for our findings and conclusions based on our objectives. We performed 

our review at Johnson Space Center and NASA Headquarters.

To assess the reversal of the Constellation Program’s decision to use the metric system as 

the standard unit of measure and its long-term impact on the Agency, we reviewed the 

following Federal laws, and NASA regulations, policies, procedures, directives, and 

presentations:

• “Metric Conversion Act of 1975;” Public Law 94-168, enacted December 23, 

1975; Title 15 of the U.S. Code -- 15 USC 205a;

• “Metric Usage in Federal Government Programs,” Executive Order 12770, 

56 Federal Register 35801, July 25, 1991;

• Omnibus Trade and Competitiveness Act of 1988 (Public Law 100-418);

• OMB Circular No. A-94, “Guidelines and Discount Rates for Benefit-Cost 

Analysis of Federal Programs,” October 29, 1992;

• NPD 8010.2E, “Use of the SI (Metric) System of Measurement in NASA 

Programs,” March 4, 2007;

• NPR 7120.5D, “ NASA Space Flight Program and Project Management 

Requirements,” March 26, 2007;

• Constellation Program Management Directive No. 030, “Use of SI as the Primary 

System of Measure for the Constellation Program, Projects, Systems and 

Missions,” December 17, 2007; 

• Constellation Program Draft Management Directive, “Use of a Hybrid System of

Units, and English as the Primary System of Measure for the Constellation 

Program, Projects, Systems and Missions,” no date;
APPENDIX A

20 REPORT NO. IG-10-011

• Constellation Program Control Board Directive No. 000390, “Direct 

Implementation for Use of a Hybrid System of Units and U.S. Customary 

(in-pound) System as the Primary System of Measure for the Constellation 

Program, Projects, System and Missions,” August 6, 2009;

• “Use of SI Units for Future NASA Programs,” Office of Program Analysis and 

Evaluation, March 20, 2006;

• “Constellation Program Units Directive Workshop,” August 26-27, 2008; and

• “Constellation Acceleration Study Report,” December 18, 2008.

We interviewed personnel from the Office of Chief Engineer, Program Analysis and 

Evaluation Office, Exploration Systems Mission Directorate, Constellation Program, 

Commercial Crew and Cargo Office, and ISS Program. We also interviewed personnel 

from NIST.

We did not use computer-processed data to perform this review. 

Prior Coverage

NASA OIG and the Government Accountability Office (GAO) have issued two reports of 

particular relevance to the subject of this memorandum. Unrestricted reports can be 

accessed over the Internet at

http://www.hq.nasa.gov/office/oig/hq/old/inspections_assessments/index.html (NASA)

and http://www.gao.gov (GAO).

National Aeronautics and Space Administration

“Assessment of NASA’s Use of the Metric System” (G-00-021, February 20, 2001)

Government Accountability Office

“Constellation Program Cost and Schedule Will Remain Uncertain Until a Sound 

Business Case is Established” (GAO-09-844, August 26, 2009)
APPENDIX B

REPORT NO. IG-10-011 21

NPD 8010.2E “USE OF THE SI

(METRIC) SYSTEM OF 

MEASUREMENT IN NASA

PROGRAMS”
APPENDIX B

22 REPORT NO. IG-10-011
APPENDIX B

REPORT NO. IG-10-011 23
APPENDIX B

24 REPORT NO. IG-10-011
APPENDIX B

REPORT NO. IG-10-011 25
APPENDIX C

26 REPORT NO. IG-10-011

NIST LETTER TO NASA
APPENDIX D

REPORT NO. IG-10-011 27

NASA’S RESPONSE TO NIST
APPENDIX D

28 REPORT NO. IG-10-011
APPENDIX E

REPORT NO. IG-10-011 29

MANAGEMENT COMMENTS
APPENDIX E

30 REPORT NO. IG-10-011
APPENDIX E

REPORT NO. IG-10-011 31
APPENDIX E

32 REPORT NO. IG-10-011
APPENDIX F

REPORT NO. IG-10-011 33

REPORT DISTRIBUTION

National Aeronautics and Space Administration

Administrator

Deputy Administrator

Chief Technologist

Associate Administrator, Program Analysis and Evaluation

Chief Engineer

Associate Administrator, Exploration Systems Mission Directorate 

Program Manager, Constellation Program

Non-NASA Organizations and Individuals

Office of Management and Budget

Deputy Associate Director, Energy and Science Division

Branch Chief, Science and Space Programs Branch

Government Accountability Office

Director, Defense, State, and NASA Financial Management, Office of Financial 

Management and Assurance

Director, NASA Issues, Office of Acquisition and Sourcing Management

Congressional Committees and Subcommittees, Chairman and 

Ranking Member

Senate Committee on Appropriations

Subcommittee on Commerce, Justice, Science, and Related Agencies

Senate Committee on Commerce, Science, and Transportation

Subcommittee on Science and Space

Senate Committee on Homeland Security and Governmental Affairs

House Committee on Appropriations

Subcommittee on Commerce, Justice, Science, and Related Agencies

House Committee on Oversight and Government Reform

Subcommittee on Government Management, Organization, and Procurement

House Committee on Science and Technology

Subcommittee on Investigations and Oversight

Subcommittee on Space and Aeronautics

REPORT NO. IG-10-011 35

Major Contributors to the Report:

Raymond Tolomeo, Acting Director, Space Operations Directorate

Lawrence Neu, Aerospace Technologist, Project Manager

Loretta Atkinson, Project Advisor

Eugene Bauer, Audit support

Janet Overton, Editor
MARCH 29, 2010

REPORT No. IG-10-011

OFFICE OF AUDITS

OFFICE OF INSPECTOR GENERAL

ADDITIONAL COPIES

To obtain additional copies of this report, contact the Assistant Inspector General for Auditing at 

202-358-1232.

SUGGESTIONS FOR FUTURE AUDITS

To suggest ideas for or to request future audits, contact the Assistant Inspector General for Auditing. 

Ideas and requests can also be mailed to:

Assistant Inspector General for Auditing

NASA Headquarters

Washington, DC 20546-0001

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To report fraud, waste, abuse, or mismanagement, contact the NASA OIG Hotline at 800-424-9183 or 

800-535-8134 (TDD). You may also write to the NASA Inspector General, P.O. Box 23089, L’Enfant

Plaza Station, Washington, DC 20026, or use http://oig.nasa.gov/hotline.html#form. The identity of 

each writer and caller can be kept confidential, upon request, to the extent permitted by law.