Thermal control concepts and designs without radioactive materials for long lived planetary landers

Paper number

IAC-09.C2.7.6

Author

Mr. Riccardo Nadalini, Active Space Technologies, Germany

Year

2009

Abstract

In the course of the future exploration of the solar system, several small robotic missions on the surfaces of the Moon and Mars will be needed to prepare and later support the human exploration of these planetary bodies. Most of them, being sophisticated science missions, (e.g. networked research missions) or more mundane monitoring stations (e.g. weather stations), will need to be miniaturized but, at the same time, to be active for long periods of time.
The designs currently in use, as well as most of those planned for the future, rely on the use of radioactive materials to some extent: either for power generation (Radioactive Thermal Generation) or simply to provide heating (Radioactive Heating Units) to prolong the life of critical systems (batteries).
These technologies are reasonably safe and well developed but the inherent danger and the public fears connected to radioactive materials generate political, legal and public relations hurdles that increase the costs and the burocratic difficulties of the missions using them. 
the case is especially sensitive in most European countries (with the exception of France and the United Kingdom), where nuclear technologies are seen with a wary eye by the public.
Alternative designs differ from the radionuclide-based ones mainly in the thermal control and in the power systems. 
In the present paper alternative designs of this two critical systems are devised, simulated and compared, for the two different cases of the Moon and Mars. 
Thermal control systems are enhanced with a self-design heat storage unit, to help keep the batteries in an optimal temperature range and prevent their degradation and increase their effective life.
Assisting components for the electrical system (supercondensators) are also introduced to try to homogenize the load profiles of the batteries (reduced depth of discharge) thus allowing for smaller batteries and more cycles.
In the end the resulting designs are compared with radionuclide-based ones in terms of increase in lifetime as well as in costs, mass and risks, to evaluate and measure which combination of technologies could better guarantee the long term survival of a small surface module.

Abstract document

IAC-09.C2.7.6.pdf

Manuscript document

IAC-09.C2.7.6.pdf (🔒 authorized access only).

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