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The Mars Science Laboratory (MSL) mission to land a large rover on Mars is being prepared for Launch in 2011. A Multi-Mission Radioisotope Thermoelectric Generator (MMRTG) on the rover provides an electrical power of 110 W for use in the rover and the science payload. Unlike the solar arrays, MMRTG provides a constant electrical power during both day and night for all seasons (year around) and latitudes. The MMRTG dissipates about 2000 W of waste heat to produce the desired electrical power. One of the challenges for MSL Rover is the thermal management of the large amount of MMRTG waste heat. During operations on the surface of Mars this heat can be harnessed to maintain the rover and the science payload within their allowable limits during nights and winters without the use of electrical survival heaters. A mechanically pumped fluid loop heat rejection and recovery system (HRS) is used to pick up some of this waste heat and supply it to the rover and payload.

The Mars Science Laboratory (MSL1) mission to land a large rover on Mars is being planned for Launch in 2009. As currently conceived, the rover would use a Multi-mission Radioisotope Thermoelectric Generator (MMRTG) to generate about 110 W of electrical power for use in the rover and the science payload. Usage of an MMRTG allows for a large amount of nearly constant electrical power to be generated day and night for all seasons (year around) and latitudes. This offers a large advantage over solar arrays. The MMRTG by its nature dissipates about 2000 W of waste heat. The basic architecture of the thermal system utilizes this waste heat on the surface of Mars to maintain the rover's temperatures within their limits under all conditions. In addition, during cruise, this waste heat needs to be dissipated safely to protect sensitive components in the spacecraft and the rover.

Multi Layer Insulation (MLI) is very commonly used in all spacecraft for heat conservation. In most instances one has to deal with MLI facing space or other cold surfaces while protecting the thermally controlled surface at more moderate temperatures than the heat sink. But in some instances, either in steady state or transient modes, one has to deal with the MLI facing the sun. Examples of such situations are during spacecraft turns, deliberate or inadvertent, when the MLI is exposed to solar insolation for short or extended periods. The effective emittance of MLI is commonly used to describe its heat loss behavior in the absence of solar incidence and is well documented in widespread literature based on measurements and rules of thumb from practice. However, when MLI faces the sun, its effective solar absorptance comes into play to determine its effectiveness in controlling the temperature of the object that it was designed to protect thermally.