Simulation and Adaptive Control of an Oxygen Production Plant for Planet Mars

Introduction

The center concerned itself primarily with the question of the production of oxygen from locally available resources. Rocket fuel consists always of at least two separate components: the fuel itself, e.g. hydrogen, and the oxygen that is required to burn the fuel in outer space. For example, one way to free up energy would be to "burn" hydrogen into water by use of oxygen.

In general, the fuel itself is much less heavy than the oxygen. When bruning hydrogen, the oxygen weighs eight times more than the hydrogen. For this reason, it is economically interesting, to produce the oxygen from locally available resources, and only carry the fuel along for the flight back to planet Earth.

The CULPR center worked primarily on three separate projects:

1. the extraction of oxygen from lunar regolith,
2. the extraction of oxygen from carbonaceous asteroids, and
3. the extraction of oxygen from the atmosphere of planet Mars.

The project that is described here concerned itself with the extraction of oxygen from the atmosphere of planet Mars. A prototype of a fully automated oxygen extraction plant was built and tested in the lab. It was foreseen that a space capable version of this extraction plant be flown to planet Mars around 2015, where it would produce and store oxygen during 2 years, oxygen that subsequently would be used as propellant for the flight back to planet Earth of a manned mission to Mars.

The Martian atmosphere consists to a large extent of CO₂ gas at a low atmospheric density of roughly 8 mbar. The temperature of the air is somewhere around -20^o centigrade. The atmosphere is first being compressed to 1 bar. The atmosphere heats up in the process. Subsequently, the atmosphere is being heated to 800 K. At that temperature, CO₂ decays to CO and O₂.

Carbon monoxide and oxygen are difficult to separate, as the molecular weights of these two gasses are very similar (32 bzw. 36, respectively). The separation was accomplished in a catalytic process involving a Zirconium membrane.

The separated oxygen gas now had to be cooled down. A heat exchanger unit was used to recuperate the heat for reuse in the heating stage of the carbon dioxide.

My own group concerned itself with questions of thermodynamical modeling of the extraction process, as well as with the design of suitable process monitoring software.

Most Important Publications

1. Marner, W.J., J.W. Suitor, L.C. Schooley, and F.E. Cellier (1990), Automation and Control of Off-Planet Oxygen Production Processes, Proc. Space'90, Engineering, Construction, and Operation in Space, New York, Vol.1, pp.226-235.

2. Chi, S.D., B.P. Zeigler, and F.E. Cellier (1991), Model-Based Task Planning System for a Space Laboratory Environment, Proc. SPIE Symp. on Cooperative Intelligent Robots in Space, Boston, MA, Vol.1387, pp.182-193.

3. Zeigler, B.P., S.D. Chi, and F.E. Cellier (1991), Model-Based Architecture for High Autonomy Systems, Engineering Systems with Intelligence - Concepts, Tools and Applications (S.G. Tzafestas, ed.), Kluwer Academic Publishers, Dordrecht, the Netherlands, pp.3-22.

4. Cellier, F.E., L.C. Schooley, B.P. Zeigler, A. Doser, G. Farrenkopf, J.W. Kim, Y.D. Pan, and B. Williams (1992), Watchdog Monitor Prevents Martian Oxygen Production Plant from Shutting Itself Down During Storm, Proc. ISRAM'92, International Symposium on Robotics and Manufacturing, Santa Fe, NM, pp.697-704.

5. Schooley, L.C., B.P. Zeigler, F.E. Cellier, and F.Y. Wang (1993), High-Autonomy Control of Space Resource Processing Plants, IEEE Control Systems, 13(3), pp.29-39.

Sponsors

• NASA

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