23, July 2014

PROJECT TITLE: Concept development and technology evaluation for a PEM fuel cells based auxiliary power unit for space applications – PEMSAPU

Coordinator: National R&D Institute for Cryogenics and Isotopic Technologies ICIT Rm. Valcea 


  • National R&D Institute for Gas Turbines COMOTI Bucharest
  • S.C. AEROFINA S.A. Bucharest

Period: 29 November 2013 – 28 November 2015

Project director: Dr. Mihai Varlam

Project team: Human resources involved in the project are estimated at 94 person-months.

Description: The Auxiliary Power Unit (APU) is a subsystem of the spacecraft power system, providing energy for functions other than propulsion. During time, different solutions were adopted for APU. From the available options that are compatible with a given mission and its environment, the best combination of energy source, energy conversion, and energy storage technologies must meet multiple criteria, but the primary criteria are always low mass and low life-cycle cost. 

Because the use of existing battery technology for energy storage in space applications is limited, the use of the Proton Exchange Membrane (PEM) fuel cells stack (FCS) is considered to solve the problem of energy storage for the spacecrafts already using liquid hydrogen and oxygen for propulsion. 

Some aspects related to fuel cells (FCs) lead us to believe that they are entitled to become the most widely used energy converter for space applications: Manned space missions have to be characterized by the synergy between their major systems: the Life Support systems, the Power Management systems and the In Situ Resource Utilization systems, which all share the use of oxygen (O2) and hydrogen (H2). Fuel cells energy converter complies  from the start with these synergies, allowing sharing of resources.

The APU concept for space applications using FCs as energy converter has as primary energy source the solar radiation (PV cells). A rechargeable battery of much lower capacity  than in the case of operating as an unique power storage unit is used to compensate the reduced ability to respond to fast load variations of the PEM FCS, and a small electrolyzer could be used in the periods of excess electricity to generate hydrogen and oxygen from the FCS produced water, thus eliminating wastes.  The aforementioned issues are specific to spacecraft and have not been synergistically addressed previously. The experimental analysis of the APU operational parameters will allow a critical evaluation of the PEM FCS based APU for space applications technology.

Project objectives:

The general objectives of the project consist in: 

  • Developing and promoting the national research capacities in the field of Auxiliary Power Units based on PEM fuel cells for space applications.
  • Improving the collaboration between R&D institutes and industry partners.
  • Multidisciplinary continuous training of specialists in hydrogen energy, renewable energy technology and systems, fuel cells, mathematical modeling and simulation, automation, technology control using modern and novel control tools.
  • In order to develop an APU concept based on PEM fuel cells and to assess the technology of implementing it on a low power  functional model for space applications, there are some specific objectives which will contribute to this achievement:
  • Realizing of a study about the design criteria of an APU based on PEM fuel cells for space applications.
  • Elaborating the APU math model. Simulations in order to establish the functioning parameters range and the design parameters.
  • Achievement of a low power PEM FCs APU experimental model.
  • Case study on the low power APU based on PEM fuel cells for space applications. 
  • Evaluation of the technology for a low power APU based on PEM fuel cells for space applications.
  • Project results dissemination. 


  • Stage 1. Considerations regarding the specific conditions of the usage of fuel cells supplied with hydrogen in space applications. 15.12.2013


T.5.1 Organization of the opening for the project consultation-dissemination of the project expected outcomes. 


Meeting report. 

  • Stage 2. Determine the optimal solution for an APU in space application. 15.06.2014


T2.1. Elaboration of a comparative study regarding the usage of various types of APU for space applications. 

T2.2. Definition of the operating conditions for the fuel cells supplied with hydrogen for space applications. 

T2.5 Elaborating the referential for the considered system. 


– Comparative study regarding the use of various types of APU in space application. 

–  Report regarding the operating conditions of the fuel cells supplied with hydrogen for space applications. 

–Referential for APU. 

  • Stage 3. Design and  development  of the experimental model for APU. 15.12.2014


T2.3  Determination of an APU configuration for space aplication.

T2.4 Elaboration of a mathematical model proposed to be developed in the previously established configuration. 

T4.1 Experimental determinations and testing of the fuel cell stack for various space environment functioning conditions corelated with T2.2. 

T.5.3 Website development and its upgrading throughout the entire project progress. 

T3.1 Design and development of the experimental model. Elaboration of the execution projects and achievement of the experimental model. 

T3.2  Elaboration of the optimized energy management algorithm for APU. 

T4.2   Experiments and tests for the optimized energy management solution on APU. 


– Configuration of an APU for space application.

-Mathematical model for simulating the established configuration.  

-Testing report for the fuel cell stack. Results evaluation. 

-Webpage of the project– hosted by the coordinator’s site.

-Execution projects. Experimental model for APU.

-Optimized energy management strategy for APU. Execution project consisting in hardware and programs packages. – Testing report.

  • Stage 4. Testing of the APU concept. Determination of the functional performances.28.11.2015.


T4.3 Testing APU in P2’s laboratories. Establishment of functional performances. 

T.5.4 Elaboration of scientific articles to be be published in scientific publications. Elaboration of a patent application. 

T4.4  Elaboration of a technology evaluation regarding the APU concept in the established configuration and on the bases of the achieved performances. 


-Two scientific papers approved by publications, showing the project’s outcomes. Patent application.

-Testing report of APU. Product information sheet. 

-Technology evaluation study

Contributions to the STAR programme objectives:

The project will clearly show the potential of Romanian entities to work in an advanced technological field as PEM fuel cells based Auxiliary Power Units is. This will have great impact at National level since the high level available and new created technology and other resources will be used at full capacity, increasing the competitiveness of the research and industry partners and making them able to integrate in ESA’s activities.

In accordance with ESAs Technology programmes, a critical evaluation of international APU existing solutions will be realized in order to introduce an improved  PEM FCs APU to be widely used  in space  and not only there.

The project aligns to the objectives of STAR Program (Space Technology and Advanced Research) by: 

  • identifying  research niche, at national, European and international level;  
  • developing and promoting the national capacity of research  in space, aeronautics, security and other related fields;
  • improving collaboration between research and industry entities;
  • multidisciplinary training of high level specialists;
  • finding ways to use space research results in usual activities. 

The project will open new partnership opportunities capable to give increased competitiveness.

It will contribute to the continuous integration of Romanian specialists into the exclusivist branch of researchers and engineers working for European Space Agency or other entities connected to European space missions. The connections that will appear will increase competitiveness for both Romanian and European specialists.

Homepage: PEMSAPU