Mark A. Hoberecht

Glenn Research Center, Cleveland, Ohio

Ian J. Jakupca

QinetiQ North America, Inc., Cleveland, Ohio

Development Status of PEM Non-Flow-Through

Fuel Cell System Technology for NASA Applications

NASA/TM—2011-217107

November 2011
NASA STI Program . . . in Profi le

Since its founding, NASA has been dedicated to the 

advancement of aeronautics and space science. The 

NASA Scientifi c and Technical Information (STI) 

program plays a key part in helping NASA maintain 

this important role.

The NASA STI Program operates under the auspices 

of the Agency Chief Information Offi cer. It collects, 

organizes, provides for archiving, and disseminates 

NASA’s STI. The NASA STI program provides access 

to the NASA Aeronautics and Space Database and 

its public interface, the NASA Technical Reports 

Server, thus providing one of the largest collections 

of aeronautical and space science STI in the world. 

Results are published in both non-NASA channels 

and by NASA in the NASA STI Report Series, which 

includes the following report types:

• TECHNICAL PUBLICATION. Reports of 

completed research or a major signifi cant phase 

of research that present the results of NASA 

programs and include extensive data or theoretical 

analysis. Includes compilations of signifi cant 

scientifi c and technical data and information 

deemed to be of continuing reference value. 

NASA counterpart of peer-reviewed formal 

professional papers but has less stringent 

limitations on manuscript length and extent of 

graphic presentations.

• TECHNICAL MEMORANDUM. Scientifi c 

and technical fi ndings that are preliminary or 

of specialized interest, e.g., quick release 

reports, working papers, and bibliographies that 

contain minimal annotation. Does not contain 

extensive analysis.

• CONTRACTOR REPORT. Scientifi c and 

technical fi ndings by NASA-sponsored 

contractors and grantees.

• CONFERENCE PUBLICATION. Collected 

papers from scientifi c and technical 

conferences, symposia, seminars, or other 

meetings sponsored or cosponsored by NASA.

• SPECIAL PUBLICATION. Scientifi c, 

technical, or historical information from 

NASA programs, projects, and missions, often 

concerned with subjects having substantial 

public interest.

• TECHNICAL TRANSLATION. Englishlanguage translations of foreign scientifi c and 

technical material pertinent to NASA’s mission.

Specialized services also include creating custom 

thesauri, building customized databases, organizing 

and publishing research results.

For more information about the NASA STI 

program, see the following:

• Access the NASA STI program home page at 

http://www.sti.nasa.gov

• E-mail your question via the Internet to help@

sti.nasa.gov

• Fax your question to the NASA STI Help Desk 

at 443–757–5803

• Telephone the NASA STI Help Desk at

 443–757–5802

• Write to:

 NASA Center for AeroSpace Information (CASI)

 7115 Standard Drive

 Hanover, MD 21076–1320
Mark A. Hoberecht

Glenn Research Center, Cleveland, Ohio

Ian J. Jakupca

QinetiQ North America, Inc., Cleveland, Ohio

Development Status of PEM Non-Flow-Through

Fuel Cell System Technology for NASA Applications

NASA/TM—2011-217107

November 2011

National Aeronautics and

Space Administration

Glenn Research Center

Cleveland, Ohio 44135
Available from

NASA Center for Aerospace Information

7115 Standard Drive

Hanover, MD 21076–1320

National Technical Information Service

5301 Shawnee Road

Alexandria, VA 22312

Available electronically at http://www.sti.nasa.gov

Trade names and trademarks are used in this report for identifi cation 

only. Their usage does not constitute an offi cial endorsement, 

either expressed or implied, by the National Aeronautics and 

Space Administration.

Level of Review: This material has been technically reviewed by technical management. 

This report contains preliminary fi ndings, 

subject to revision as analysis proceeds.
NASA/TM—2011-217107 1 

Development Status of PEM Non-Flow-Through Fuel Cell System 

Technology for NASA Applications 

Mark A. Hoberecht 

National Aeronautics and Space Administration 

Glenn Research Center 

Cleveland, Ohio 44135 

Ian J. Jakupca 

QinetiQ North America, Inc. 

Cleveland, Ohio 44135 

Background 

Today’s widespread development of proton-exchange-membrane (PEM) fuel cell technology for 

commercial users owes its existence to NASA, where fuel cell technology saw its first applications. 

Beginning with the early Gemini and Apollo programs, and continuing to this day with the Shuttle Orbiter 

program, fuel cells have been a primary source of electrical power for many NASA missions. This is 

particularly true for manned missions, where astronauts are able to make use of the by-product of the fuel 

cell reaction, potable water. But fuel cells also offer advantages for unmanned missions, specifically when 

power requirements exceed several hundred watts and primary batteries are not a viable alternative. 

In recent years, NASA’s Exploration Technology Development Program (ETDP) funded the 

development of fuel cell technology for applications that provide both primary power and regenerative 

fuel cell energy storage for planned Exploration missions that involved a return to the moon. Under this 

program, the Altair Lunar Lander was a mission requiring fuel cell primary power. There were also 

various Lunar Surface System applications requiring regenerative fuel cell energy storage, in which a fuel 

cell and electrolyzer combine to form an energy storage system with hydrogen, oxygen, and water as 

common reactants. Examples of these systems include habitat modules and large rovers. In FY11, the 

ETDP has been replaced by the Enabling Technology Development and Demonstration Program 

(ETDDP), with many of the same technology goals and requirements applied against NASA’s revised 

Exploration portfolio. 

NASA has a unique set of requirements for fuel cells when compared to commercial PEM fuel cell 

technology. These requirements result from the space environment, and include operation with pure 

oxygen (instead of air), and water management in reduced and zero-gravity. Because these requirements 

are so unique, commercial PEM fuel cell technology is not directly applicable to NASA’s needs. 

However, over the past decade NASA pursued a development path to modify commercial PEM fuel cell 

technology for NASA applications, and recently focused specifically on non-flow-through PEM fuel cell 

development. This paper addresses the status of that development. The goals for the technology 

development effort are depicted in Table 1, which identifies the key performance parameters for the 

various mission users. 
NASA/TM—2011-217107 2 

TABLE 1.—FUEL CELL KEY PERFORMANCE PARAMETERS 

Customer Need Performance Parameter SOA 

(alkaline) 

Current 

Value* 

(PEM) 

Threshold 

Value** 

(@ 3 kW) 

Goal** 

(@ 3 kW) 

Altair: 

3 kW for 220 hours continuous, 

5.5 kW peak. 

Lunar Surface Systems: 

TBD kW for 15 days continuous 

operation 

Rover: TBD 

System power density 

Fuel Cell 

RFC (without tanks) 

49 W/kg 

n/a 

n/a 

n/a 

88 W/kg 

25 W/kg 

136 W/kg 

36 W/kg 

Fuel Cell Stack power density n/a n/a 107 W/kg 231 W/kg 

Fuel Cell Balance-of-plant mass n/a n/a 21 kg 9 kg 

MEA efficiency @ 200 mA/cm2 

For Fuel Cell 

Individual cell voltage 

For Electrolysis 

Individual cell voltage 

For RFC (Round Trip) 

73% 

0.90V 

n/a 

n/a 

n/a 

72% 

0.89V 

86% 

1.48 

62% 

73% 

0.90V 

84% 

1.46 

62% 

75% 

0.92V 

85% 

1.44 

64% 

System efficiency @ 200 mA/cm2 

Fuel Cell 

Parasitic penalty 

Regenerative Fuel Cell  

Parasitic penalty 

High Pressure penalty 

71% 

2% 

n/a 

n/a 

n/a 

65%** * 

10% 

n/a 

n/a 

n/a 

71% 

2% 

43% 

10% 

20% 

74% 

1% 

54% 

5% 

10% 

Maintenance-free lifetime 

Altair: 220 hours (primary) 

Surface: 10,000 hours (RFC) 

Maintenance-free operating life 

Fuel Cell MEA 

Electrolysis MEA 

Fuel Cell System (for Altair) 

Regenerative Fuel Cell System 

2500 hrs 

n/a 

2500 hrs 

n/a 

13,500 hrs 

n/a 

n/a 

n/a 

5,000 hrs 

5,000 hrs 

 220 hrs 

5,000 hrs 

10,000 hrs 

10,000 hrs 

 220 hrs 

10,000 hrs 

Introduction 

All fuel cell systems, whether for space or commercial applications, consist of one or more fuel cell 

stacks in combination with appropriate balance-of-plant hardware. The fuel cell stack performs the 

electrochemical function of breaking down hydrogen and oxygen to form water and electrical power, and 

the ancillary components comprising the balance-of-plant perform the necessary fluid and thermal 

management functions of the system. The goals of NASA’s development effort are to improve fuel cell 

stack electrical performance, reduce balance-of-plant mass, volume, and parasitic power requirements, 

and increase overall system life and reliability. The effort is being led by NASA Glenn Research Center 

(GRC) in partnership with NASA Johnson Space Center (JSC), NASA Jet Propulsion Laboratory (JPL), 

NASA Kennedy Space Center (KSC), and vendor partners. A comparison of PEM flow-through fuel cell 

technology with non-flow-through technology was addressed by this author in a recent paper (Ref. 1). A 

brief summary of that work is presented here. 

Commercial PEM fuel cell technology is flow-through in nature, where a recirculating oxygen 

reactant stream removes product water generated at the cathode surface within each individual cell of the 

fuel cell stack. A recirculating reactant stream dictates the need for some type of device to initiate and 

sustain the recirculating flow, and another device to separate the product water from the two-phase stream 

exiting the stack. In the case of existing state-of-the-art (SOA) flow-through PEM fuel cell systems, these 

devices are typically active mechanical components such as the pump and water separator in Figure 1. 

Any fuel cell system using these active components bears their weight, volume, parasitic power, 

reliability, life, and cost penalties. 
NASA/TM—2011-217107 3 anode cathode coolant

MEA

H2O

gas 

recirculation 

pump

active water 

separator

H2 O2

H2O

H2O

O2

O2 / H2O

anode

cathode

coolant

MEA

H2O

gas 

recirculation 

pump

active water 

separator

H2 O2

H2O

H2O

O2

O2 / H2O

Figure 1.—Flow-through PEM fuel cell schematic (active components). 

Replacing the active components with passive components can minimize some of the resulting 

penalties. Figure 2 depicts the same flow-through technology schematic as in Figure 1, but with passive 

components replacing active mechanical components. For reactant recirculation, injectors or ejectors 

could serve as passive replacements for pumps. In the area of product water separation, membrane 

separators could replace motorized centrifugal separators. 

The penalties associated with these balance-of-plant components can be minimized even further with 

non-flow-through PEM fuel cell technology, as shown in Figure 3. Here, product water generated at the 

cathode surface wicks through a support structure across an adjacent gas cavity, through a hydrophilic 

membrane, into a water cavity within each cell of the stack. There are no recirculating reactants, and 

hence no requirement for providing either recirculation or product water separation from a two-phase 

reactant stream. Therefore, there is no need for components that provide these functions, whether they are 

active or passive. Eliminating these components therefore eliminates the penalties associated with them. 
NASA/TM—2011-217107 4 anode cathode coolant

MEA

H2O

injector/ejector

passive water 

separator

H2 O2

H2O

H2O

O2

O2 / H2O

anode

cathode

coolant

MEA

H2O

injector/ejector

passive water 

separator

H2 O2

H2O

H2O

O2

O2 / H2O

Figure 2.—Flow-through PEM fuel cell schematic (passive components). anode cathode

H

O2

MEA

H2O

H2 O2

H2O

H2O

coolant

hydrophilic membrane

anode

cathode

H

O2

MEA

H2O

H2 O2

H2O

H2O

coolant

hydrophilic membrane

Figure 3.—Non-flow-through PEM fuel cell schematic. 
NASA/TM—2011-217107 5 

TABLE 2.—SYSTEM-LEVEL COMPARISON OF FLOW-THROUGH 

VERSUS NON-FLOW-THROUGH TECHNOLOGY 

Design parameter Flow-through Non-flow-through 

Efficiency − −

Mass 

Volume 

Parasitic power 

Reliability 

Life 

Cost 

TRL 

The projected advantages (marked by a ) for NASA applications of non-flow-through PEM fuel cell 

technology over flow-through technology at the system level are numerous, as shown in Table 2. 

There is little difference in efficiency between the two systems because voltage performance is 

similar. The sole advantage of the flow-through technology is its higher technology readiness level 

(TRL), but this advantage has diminished with the recent success of non-flow-through development at 

several vendors. The many projected advantages of the non-flow-through PEM fuel cell technology are 

the reason why NASA continues to actively pursue its development. However, the major challenge 

remains water management within the gas cavities of the non-flow-through cell. Because non-flowthrough technology by definition is dead-ended in terms of reactant flow, there is no bulk flow of gas 

available to flush liquid water away from reactant sites within the cells. Proper design of internal cell 

structures, along with their surface properties and pore characteristics, is critical to achieving effective 

water management within non-flow-through cells. It should be noted, however, that brief purging of 

reactants through the cell remains an effective method of water management. These purges are always 

necessary in a non-flow-through fuel cell to remove gaseous inerts that accumulate over time. During 

purging, a non-flow-through fuel cell is operating in a flow-through mode. To maintain the advantages of 

non-flow-through technology over flow-through technology, the quantity and duration of these purge 

events should be minimized. 

Vendor Stack Development Status 

NASA is presently developing PEM non-flow-through fuel cell stack technology at four different 

vendors, each of whom has their own unique proprietary approach to stack design and system operation. 

Each vendor uses different materials for cell frames, gas-cavity support structures, and the hydrophilic 

membrane separating the oxygen cavity from the water cavity (see Fig. 3). Each vendor has also chosen a 

cell active area based on already-existing hardware. One of the vendors is considered the baseline vendor 

to supply PEM non-flow-through fuel cell stacks for the systems under development as part of ETDDP , 

while the other three are considered alternates, each competing for the role of back-up vendor. 

Infinity Fuel Cell and Hydrogen, Inc. is the baseline vendor, and is presently developing their stack 

technology under a Phase III Small Business Innovative Research (SBIR) contract with NASA GRC. 

Infinity’s stack technology is based on their design approach developed under previous Phase I and II 

SBIR contracts. They have built several short stacks (less than 10 cells) with active areas of both 50 cm2

and 150 cm2

. Larger active areas of greater than 100 cm2 are necessary for multi-kW sized stacks, while 

active areas less than 100 cm2

 are more appropriate for stacks under 1 kW. The existing Phase III contract 

culminates in the summer of 2012 with the delivery to NASA of two 40-cell 150 cm2

 breadboard stacks 

(30 V, 1 kW) which when tested successfully, will demonstrate a NASA Technology Readiness Level 

(TRL) of 5. At that time, and with the availability of sufficient funding, development of engineering 

model stacks will be initiated with the goal of demonstrating a TRL of 6 through testing in a relevant 

environment. 
NASA/TM—2011-217107 6 

TABLE 3.—NON-FLOW-THROUGH PEM FUEL CELL TECHNOLOGY VENDOR COMPARISON 

Parameter Infinity ElectroChem Proton Teledyne 

Active area (cm2) 50 and 150 200 86 69 

Operating temperature (C) 60 75 75 55 

Operating pressure (psig) 30 30 50 10 

Max oxygen/Water ΔP (psig) 8 30 4 5 

Pressure Control Sensitivity Medium Low Very high High 

Peak steady state current 

density (mA/cm2

) 

500 350 400 200 

Pass load profile test? Yes No No No 

Orientation sensitivity None TBD TBD TBD 

The first alternate vendor is ElectroChem, Inc., who provided their stack under a Phase III Small 

Business Innovative Research (SBIR) contract through NASA JSC. The ElectroChem stack technology 

was also developed under previous Phase I and II SBIR contracts, and is now at an active area of 200 cm2

. 

The next alternate vendor is Proton Energy Systems, Inc., whose non-flow-through stack technology was 

developed under a Phase II SBIR contract with NASA KSC. Proton’s development is derived from 

previous NASA unitized regenerative fuel cell (URFC) SBIR work, and is presently at an active area of 

86 cm2

. The last alternate vendor is Teledyne Energy Systems, Inc., who developed non-flow-through 

stack technology under funding from two sources, company internal research and development (IR&D) 

and the NASA Innovative Partnership Program (IPP). Teledyne stack technology is presently at an active 

are of 69 cm2

. 

Each vendor has conducted in-house testing of their non-flow-through stack technology, and 

successfully demonstrated its performance. Testing by the baseline vendor has been extensive, while 

testing by all the alternate vendors was more limited. NASA has conducted a series of tests on stacks 

from all four vendors, and a comparison of various parameters based on these tests is shown in Table 3. 

The first three parameters in the table are stack characteristics specific to each vendor’s technology, 

with no impact on performance. An assessment of performance begins with the fourth and fifth 

parameters, which represent operating pressure and pressure control sensitivity. A higher number for the 

differential pressure between the cell oxygen and water cavities reflects a more robust cell design, and 

also allows less stringent pressure control. The sixth and seventh parameters, peak steady state current 

density and ability to pass the load profile test, are in this case most likely a reflection of the effectiveness 

of the water removal process for the various stacks. Although several factors could contribute to lower 

current density capability, in these tests it was noted that cell flooding was readily observed while 

operating at higher current densities. Only the vendor’s stack with the highest current density value, the 

baseline vendor, was capable of passing the NASA load profile test by completing the entire load profile 

with no low-voltage shutdowns, as shown in Figure 4. An example of an alternate vendor’s stack failing 

the test because of a low-voltage shutdown is also shown. An assessment of the last parameter, orientation 

sensitivity, was only conducted on stacks from the baseline vendor, where orientation had no impact. 

Orientation sensitivity for stacks from the three alternate vendors will be determined in the near future. 

More detailed testing of all the vendor stacks will be conducted over the coming months. Key 

parameters to be evaluated during that time include stack efficiency, mass and volume, manufacturability, 

and stable long-term operation. At the conclusion of these detailed evaluations, the NASA fuel cell team 

will down-select a back-up vendor. At some point in the future, and should additional funding be 

available, NASA will initiate a parallel development effort for TRL-6 engineering model stacks. 
NASA/TM—2011-217107 7 

Figure 4.—NASA load profile test. 

NASA Balance-of-Plant Development Status 

The PEM non-flow-through fuel cell balance-of-plant hardware is being developed in-house at NASA 

GRC. The present focus of the effort is development of a common system architecture, shown in 

Figure 5, which can be used to test hardware from the component level through the system level. The 

balance-of-plant effort is proceeding along two fronts; a versatile common test platform to test fuel cell 

stacks from multiple vendors, and a compact balance-of-plant design to evaluate mass and volume 

reduction options using the fuel cell stack design from the baseline vendor. 

The common system architecture consists of various modules, each with specific functions. At the 

core of the architecture is the Fuel Cell Stack. The kinetics within the stack determines the system 

architecture. These kinetics include electrical, fluidic, hydraulic, and thermal phenomenon. The Reactant 

Manifold Module is required to control three fluids (hydrogen reactant gas, oxygen reactant gas, liquid 

product water), in this case using a pair of pressure control components for each fluid. The Cooling 

Module removes any excess heat generated by the fuel cell stack, and is the dominant parasitic load in the 

system. The Power Interface Module distributes power between the Fuel Cell Stack and both the External 

System and Cooling Module through some combination of power conditioning and switching. Delivery of 

the hydrogen and oxygen gaseous reactants to the system is accomplished with the Reactant Supply 

Module. An Electronics Module is used to monitor several system operating parameters to safely control 

the system, and an internal Power Conditioning Module provides regulated power to ensure high quality 

sensor data and uninterrupted computer control. The separate nature of these modules provides flexibility 

in terms of scale-up for larger stacks or higher power capabilities as the non-flow-through fuel cell system 

technology matures. 
NASA/TM—2011-217107 8 

Figure 5.—Common system architecture. 

Based on the common system architecture, a versatile common test platform has been designed, built, 

and certified to test non-flow-through PEM fuel cell stacks from multiple vendors. The test platform, 

shown in Figure 6, incorporates all modules from the common system architecture with the exception of 

the Reactant Supply Module. It is capable of testing a stack up to 1 kW in power, with up to 40 cells. 

Using NASA customized software, the common test platform controls absolute and differential pressures, 

as well as stack temperature within user-defined limits. The computerized safety system autonomously 

initiates a shut down in the event that any selectable safety parameter has exceeded its permitted range. 

The compact balance-of-plant design, shown in Figure 7, is a model of the common system 

architecture re-packaged for field applications. The entire Reactant Manifold Module has been 

incorporated into the fuel cell stack end plate. By maintaining the common system architecture, all system 

fluidic, structural, and thermal aspects are simplified. This results in increased volumetric efficiency 

without modifications to the electronic hardware, software, or operational procedures. A field 

demonstration of the compact balance-of-plant integrated into an actual fuel cell system is planned for the 

near future. 
NASA/TM—2011-217107 9 

Figure 6.—Versatile common test platform. 

Figure 7.—Compact balance-of-plant design. 
NASA/TM—2011-217107 10 

Summary 

Fuel cells have a successful history of supplying electrical power for many past NASA missions, 

including Gemini, Apollo, and the Shuttle Orbiter. For use in future missions, NASA has been developing 

advanced PEM fuel cell technology for the past decade by leveraging past commercial development and 

adapting it to NASA’s unique set of space requirements. Initially this development was concentrated on 

flow-through PEM fuel cell technology because of its commercial legacy. Over the past several years, 

however, the focus has shifted to non-flow-through PEM fuel cell technology because of its many 

projected system advantages, which include mass, volume, parasitic power, reliability, life, and cost. 

Four different vendors, one baseline and three alternates, are presently developing non-flow-through 

PEM fuel cell technology for future NASA missions. Each vendor has a unique, proprietary approach. 

The baseline vendor, Infinity Fuel Cell and Hydrogen, Inc., has delivered several short stacks to NASA 

over the past two years for test and evaluation, and is presently under contract to deliver two 40-cell 

150 cm2

 breadboard stacks to NASA GRC in the summer of 2012. The three alternate vendors—

ElectroChem, Inc., Proton Energy Systems, Inc., and Teledyne Energy Systems, Inc.—have each 

delivered short stacks to NASA over the past year for test and evaluation. Initial testing has now been 

performed on stacks from all four vendors, and a preliminary evaluation has been conducted. Following 

more detailed testing over the coming months, a more complete assessment can be conducted allowing a 

back-up vendor to be selected. Going forward, and should additional funding be available, both the 

baseline and back-up vendors will be awarded contracts to develop engineering model fuel cell stacks to a 

NASA TRL of 6, which will require testing in a relevant environment. 

References 

1. Hoberecht, M.A., NASA Glenn Research Center, “A Comparison of Flow-Through Versus NonFlow-Through Proton Exchange Membrane Fuel Cell Systems for NASA’s Exploration Missions,” 

NASA/TM—2010-216107. 
REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188 

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the 

data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this 

burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. 

Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB 

control number. 

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 

1. REPORT DATE (DD-MM-YYYY)

01-11-2011 

2. REPORT TYPE

Technical Memorandum 

3. DATES COVERED (From - To)

4. TITLE AND SUBTITLE

Development Status of PEM Non-Flow-Through Fuel Cell System Technology for NASA 

Applications 

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

Hoberecht, Mark, A.; Jakupca, Ian, J. 

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

WBS 038957.04.06.01.03 

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration 

John H. Glenn Research Center at Lewis Field 

Cleveland, Ohio 44135-3191 

8. PERFORMING ORGANIZATION

 REPORT NUMBER

E-17783 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Aeronautics and Space Administration 

Washington, DC 20546-0001 

10. SPONSORING/MONITOR'S

 ACRONYM(S)

NASA 

11. SPONSORING/MONITORING

 REPORT NUMBER

NASA/TM-2011-217107 

12. DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified-Unlimited 

Subject Categories: 15, 20, and 44 

Available electronically at http://www.sti.nasa.gov 

This publication is available from the NASA Center for AeroSpace Information, 443-757-5802

13. SUPPLEMENTARY NOTES

14. ABSTRACT

Today’s widespread development of proton-exchange-membrane (PEM) fuel cell technology for commercial users owes its existence to 

NASA, where fuel cell technology saw its first applications. Beginning with the early Gemini and Apollo programs, and continuing to this 

day with the Shuttle Orbiter program, fuel cells have been a primary source of electrical power for many NASA missions. This is

particularly true for manned missions, where astronauts are able to make use of the by-product of the fuel cell reaction, potable water. But 

fuel cells also offer advantages for unmanned missions, specifically when power requirements exceed several hundred watts and primary 

batteries are not a viable alternative. In recent years, NASA’s Exploration Technology Development Program (ETDP) funded the 

development of fuel cell technology for applications that provide both primary power and regenerative fuel cell energy storage for planned 

Exploration missions that involved a return to the moon. Under this program, the Altair Lunar Lander was a mission requiring fuel cell 

primary power. There were also various Lunar Surface System applications requiring regenerative fuel cell energy storage, in which a fuel 

cell and electrolyzer combine to form an energy storage system with hydrogen, oxygen, and water as common reactants. Examples of these 

systems include habitat modules and large rovers. In FY11, the ETDP has been replaced by the Enabling Technology Development and 

Demonstration Program (ETDDP), with many of the same technology goals and requirements applied against NASA’s revised Exploration 

portfolio. 

15. SUBJECT TERMS

Fuel cells; Electrochemical cells; Spacecraft propulsion; Energy conversion 

16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

 ABSTRACT

UU 

18. NUMBER

 OF 

 PAGES

16 

19a. NAME OF RESPONSIBLE PERSON

STI Help Desk (email:help@sti.nasa.gov) 

a. REPORT

U 

b. ABSTRACT

U 

c. THIS 

PAGE

U 

19b. TELEPHONE NUMBER (include area code)

443-757-5802 

Standard Form 298 (Rev. 8-98)

Prescribed by ANSI Std. Z39-18