Preparation of the MMRTG for the Mars Science Laboratory Mission

Abstract

The multi-mission Radioisotope Thermoelectric Generator (RTG), or MMRTG, was developed to be a workhorse unit for a variety of potential future missions. The MMRTG is capable of operating over a range of environments, from planetary atmosphere to the vacuum of space. The operating envelope spans a wide range of thermal environments providing the necessary flexibility to address a broad range of potential future missions. The high grade waste heat from MMRTG is ideal for thermal integration with the spacecraft, with the MMRTG providing both heat and electrical power to the spacecraft. The system is robust and will withstand very high launch and landing loads. The thermoelectric system is inherently radiation tolerant, making it ideal for the harshest space environments. The nuclear heat generator coupled with the solid state power conversion provides a simple, highly reliable, long life power system with no moving parts. The first use of the MMRTG is the Mars Science Laboratory (MSL) mission. The MMRTG is providing both heat and electrical power to the MSL rover, named Curiosity. The MMRTG went through a litany of tests and checkouts in preparation for the MSL mission. Initially, the MMRTG was tested as an ETG (Electrically Heated Thermoelectric Generator) to characterize the performance envelope and to ensure that the unit was acceptable to commit to fueling. Once fueled, the MMRTG went through a proto-flight acceptance test series including vibration, magnetic, thermal vacuum, and mass properties testing. These tests confirmed that the unit was acceptable for the MSL mission prior to shipping the unit to Kennedy Space Center (KSC). Once at KSC, the MMRTG underwent fit checks and final performance measurements prior to final integration with the spacecraft at the Vertical Integration Facility located at Launch Complex 41. The system was successfully launched on November 26 th , 2011 and is currently in