Mars Science Laboratory Launch Pad Thermal Control

Abstract

NASA is planning to send a large (>850 kg) rover as part of the Mars Science Laboratory (MSL) mission to Mars in 2011. The rover is powered by a Multi-mission Radioisotope Thermoelectric Generator (MMRTG), which generates about 2000 W of heat that is converted to about 110 W of electrical power for use by the rover electronics and science payload. The presence of the high thermal power MMRTG in the descent stage leads to difficult and interesting thermal problems in terms of maintaining the temperatures of the sensitive rover electronics, payload and the descent stage propulsion components within their allowable flight limits. A mechanically pumped single phase heat rejection system (HRS) using CFC-11 as the working fluid is employed to maintain the MMRTG temperature within reasonable levels by picking up its waste heat and rejecting it to the HRS radiators in the cruise stage. These radiators are cooled by the launch vehicle fairing air conditioning (A/C) system. This paper will describe the challenges faced in accommodating the warm MMRTG during the pre-launch phases of integration, launch pad operations as well as during launch. Predictions of temperatures during these phases will be presented when all the cooling systems (HRS and A/C) are operational. In-air tests conducted on the spacecraft in December 2008 to simulate the launch conditions were very successful and showed that all components would be within their allowable limits during these phases. Results of these tests will be shared in this paper.

An equivalent ground thermal test method for single-phase fluid loop space radiator

“…[13][14][15] Some of the famous missions are the Defense Satellite Program, the space shuttle orbiter, Mars Pathfinder, Mars Exploration Rover and Mars Science Laboratory. [16][17][18][19][20] For spacecraft which employs pumped fluid loops' thermal control system, most of the spacecraft waste heat is transferred to radiator by means of forced liquid convection, therefore, heat conduction and heat convection become the main heat transfer approaches between components and radiators. The heat transfer behavior between components and radiators can be simulated in normal ground pressure environment directly, because the radiation could be controlled to be less than 10% of the heat transfer.…”