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978-3-8439-1224-2, Reihe Raumfahrt
Philipp B. Hager
Dynamic thermal modeling for moving objects on the Moon
222 Seiten, Dissertation Technische Universität München (2013), Softcover, A5
In this work a new method was developed, implemented, and verified to calculate the transient thermal environment for man-made objects on the surface of the Moon. A differentiated design based on transient heat fluxes for a moving object is now possible, in contrast to the worst case design approach prevailing in spacecraft thermal engineering of today.
The thermal surface environment of the Moon is harsh and diverse, and thus poses demanding requirements to the design of surface-crafts. A lack of atmosphere and the insulating surface material lead to temperatures ranging from 25 K in permanently shadowed craters at the lunar poles to 390 K at the sub-solar point on the lunar equator. The lunar topography is characterized by craters and boulders of a large variety of sizes. Each crater and boulder alters local surface temperatures.
A new method was developed, implemented, and verified to calculate the transient thermal environment for man-made objects on the surface of the Moon. A differentiated design based on transient heat fluxes for a moving object is now possible, as an extension to worst case analyses.
The developed method was implemented into a tool, the Thermal Moon Simulator (TherMoS), which includes models for the lunar topography, the lunar regolith, boulders, craters, and an orbit propagator. A ray tracing algorithm determines solar and infrared heat fluxes, and a numerical solver calculates the temperatures.
Case studies were performed with exploration rovers of varying detail and a spacesuit in different postures. Rover and spacesuit sample bodies were set in a variety of lunar landscapes, moved along predefined paths, and performed operations imitating geological tasks.
From the results, one can conclude that paths and operations on the Moon must be investigated thoroughly in the view of local surface features and temperatures. Transient analysis can help in the profiling of mission scenarios and the derivation of requirements. In subsequent phases of a project, transient analysis can help in the design of technologies, equipment, and the entire surface-craft. Finally, transient analyses support mission operations for example thermal path planning and scheduling of tasks.
This dissertation identifies the necessity for transient calculations and provides a new method for the thermal analyses of surface-craft, to support future exploration of the surface of the Moon.