Thermal analysis of the NANOKHOD Microrover under Mercury Environment Test Conditions

Paper number

IAC-07-A5.I.-A3.I.B.12

Author

Ms. Anne-Marie Schreyer, University of Stuttgart, Germany

Coauthor

Prof. Hans-Peter Roeser, University of Stuttgart, Germany

Coauthor

Ms. Sabine Klinkner, Germany

Coauthor

Chris.G.-Y. Lee, Germany

Coauthor

Mr. Jorg Shaefer, Germany

Year

2007

Abstract

The tethered microrover Nanokhod is a small mobile scientific platform designed to transport and operate a package of scientific instruments for in-situ measurements in the vicinity of the landing point on a planetary surface.
It was recently designed to fulfil the flight model requirements of ESA’s Cornerstone mission Bepi Colombo exploring the planet Mercury.
The Rover has a volume of 160 x 65 x 250mm³ and weighs 3.2kg including its payload consisting of the camera MIROCAM and the two spectrometers APXS and MIMOS for chemical and mineralogical analysis.
The mission profile, the Nanokhod was designed for, foresees a surface investigation with a duration of 7 to14 Earth days on the night side of Mercury. This means harsh environmental conditions, namely no atmosphere and surface temperatures approaching –180°C. 
To guarantee the functioning of all components within the Roversystem in this demanding thermal environment, careful and detailed thermal design, modelling and testing of the Rover is required.
This paper will present the development process of a detailed thermal model of the Rover as preparation for the environmental testing of the hardware model.
All necessary issues for the realisation of the thermal model of the Rover are discussed, beginning with the applied assumptions and simplifications and then describing the modelling process itself.
During the development process, the model has undergone several iterations that will be described in detail: tests were performed to gain material data for the electronic boards of the Rover which were used in the model, as well as changes in the density of the grid of thermal nodes.
The results of transient and steady-state thermal analysis for different modes of operation are presented together with a sensitivity analysis that was performed to investigate the influences of different parameters (material data, number of rays in Monte Carlo Ray Tracing procedure, contact conductance).
The performed analyses prove the thermal model of the Nanokhod as a good baseline for thermal investigations for Mercury conditions as well as for future mission scenarios of the Nanokhod Microrover.

Abstract document

IAC-07-A5.I.-A3.I.B.12.pdf

Manuscript document

IAC-07-A5.I.-A3.I.B.12.pdf (🔒 authorized access only).

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