Wide Range Vacuum Pumps for the SAM Instrument on the MSL Curiosity Rover Paul Sorensen*,Robert Kline-Schoder* and Rodger Farley** Abstract Creare Incorporated and NASA Goddard Space Flight Center developed and space qualified two wide  range pumps (WRPs) that were included in the Sample Analysis at Mars (SAM) instrument [1]. This instrument was subsequently integrated into the Mars Science Laboratory (MSL) “Curiosity Rover,” launched aboard an Atlas V rocket in 2011, and landed on August 6, 2012, in the Gale Crater on Mars.The pumps have now operated for more than 18 months in the Gale Crater and have been evacuating the key components of the SAM instrument:  a quadrupole mass spectrometer, a tunable laser  spectrometer, and six gas chromatograph columns. In this paper, we describe the main design  challenges and the ways in which they were solved. This includes the custom design of a miniaturized, high-speed motor to drive the turbo drag pump rotor, analysis of rotor dynamics for super critical operation, and bearing/lubricant design/selection.  Introduction Approximately 15 years ago, the Jet Propulsion Laboratory started an initiative to fund the development of  a miniaturized vacuum system. JPL saw a need for small vacuum systems to support astrobiological science missions, including mass spectrometers and gas chromatographs. At the time, mass spectrometers and other instruments for astrobiology were being reduced in size, mass, and power.However, the bulk of the accompanying vacuum system had come to dominate the overall system design, especially since commercial vacuum systems were not designed with the constraints of space missions in mind. For astrobiological science missions such as MSL, the main requirements are the highest vacuum  level and longest life in the smallest possible package with the least amount of power consumption.These are requirements not unlike what is required for terrestrial applications of portable mass spectrometers. This paper will present miniaturized pumping system design and test data and will discuss  continuing efforts, supported by Goddard Space Flight Center (GSFC), to demonstrate long life time with repeated start-stop cycles. Miniature Vacuum Pump Background In order to achieve high vacuum levels, only a few pumping technologies are available (turbomolecular-, cryogenic-, or diffusion-pumps). Considering size and power limitations, the choices are further restricted  so that the only viable technology for long term operation is a turbomolecular pump. In a turbomolecular  pump, the rotor and stator blades push gas molecules from low to high pressure. In order to achieve high compression ratios on each turbo stage, the pump rotor tip speed needs to be comparable to the most probable molecular speed of the gas being pumped. This means that when the size of the rotor decreases to reduce pump size and mass, the rotor speed needs to increase in proportion. Also, as pump  size decreases, the pumping speed is reduced, which necessitates tighter clearances between the  moving parts of the pumps in order to control leakage back flow. Both the higher speed and the tighter clearance affect higher demand on pump parts fabrication and assembly. For astrobiological science, and Mars missions in particular, a turbomolecular pump (TMP) is coupled with a molecular drag pump (MDP) on the same shaft driven by the same electric motor drive. The molecular drag pump exhausts directly to  *Creale Incorporated, Hanover, NH **NASA Goddard Space Flight Center, Greenbelt, MD /g51/g85/g82/g70/g72/g72/g71/g76/g81/g74/g86/g3/g82/g73/g3/g87/g75/g72/g3/g23/g21/g81/g71/g3/g36/g72/g85/g82/g86/g83/g68/g70/g72/g3/g48/g72/g70/g75/g68/g81/g76/g86/g80/g86/g3/g54/g92/g80/g83/g82/g86/g76/g88/g80/g15/g3/g49/g36/g54/g36/g3/g42/g82/g71/g71/g68/g85 /g71/g3/g54/g83/g68/g70/g72/g3/g41/g79/g76/g74/g75/g87/g3/g38/g72/g81/g87/g72/g85/g15/g3/g48/g68/g92/g3/g20/g23/g16/g20/g25/g15/g3/g21/g19/g20/g23/g3 463