Lunar CubeSat Mass Spectrometer with LETS Radiation Sensor

JPL and JSC propose a single suite with two payloads sharing power and C&DH electronics to be advanced from TRL-4 to TRL-6 for prolonged operation on the Lunar Surface. JPL’s Lunar CubeSat Mass Spectrometer (LCMS) will detect trace abundance volatiles including the first measurements of Xe and Kr at 20-100× higher sensitivity than the LACE experiment on Apollo 17 (the only previous lunar surface mass spectrometer investigation). LCMS will retire a longstanding lunar science goal, documented in a series of Planetary Decadal Survey, LEAG, and NRC reports, to understand the composition of Volatile Chemical Compounds (VCC) at the surface. JSC’s Linear Energy Transfer Spectrometer (LETS) will make the first radiation measurements on the Lunar Surface, addressing important Lunar Human Exploration Strategic Knowledge Gaps (SKGs) and helping pave the way for long-term human exploration. Both the LCMS and LETS require thermal/radhard adaptations and testing to be integration with a Lunar Commercial Lander platform by the September 2022 time-frame. LCMS is a proven Quadrupole Ion Trap (QIT) Mass Spectrometer (MS) design that operated successfully on the International Space Station from 2010 to 2012. It provides up to two orders of magnitude higher sensitivity and mass resolution than GSFC’s Neutral Mass Spectrometer, with ≤1% precision isotope ratios from both atmospheric and solid samples. It can additionally perform tandem MS studies of complex organic species (capability not used for the DALI program). The LCMS’s rugged 8U design, 7 kg mass, and 22 W peak power are ~2-3× lower than current high performance flight MS designs, making it compatible with CubeSat and SmallSat mission platforms. Its low cost, modular design leverages ~15 years of QITMS maturation history at JPL, and decades of flight-proven MS electronics built by the University of Michigan. LETS is a flight spare radiation sensor built by JSC for NASA’s BioSentinel CubeSat, scheduled for launch in 2020. Its Timepix detector technology is currently operating successfully on the ISS as part of the REM and MPT instruments. The knowledge of the ISS radiation environment gained from these data sets is adding to our understanding of the radiation risks faced by astronauts in low earth orbital environments. The LETS investigation will provide further knowledge required for human exploration. LETS’ software is already fully compatible with the LCMS’s C&DH electronics, and it can be integrated with the LCMS for a very modest cost. It is only 200g in mass, and requires 2 W operating power (plus shared 7 W for power and C&DH from the LCMS). Its low mass and low power consumption make it an attractive solution for detailed sampling of the radiation field on any lunar lander. Our science goal is to use LCMS to determine which volatile species are present at the lunar surface at abundances ≥50 mol/cm3. The LCMS requires an unobstructed view of the Lunar surface to minimize the effects of Lander out-gassing. Its 30 deg field of view enables measuring exospheric atoms as they bounce across the lunar surface. LCMS’s QITMS sensor is designed to meet all performance requirements in an ultra-high vacuum environment where ion-ion and ion-neutral interactions are rare. We have already validated its performance for sensor/sample temperatures up to 300°C and show that no helium buffer gas is required. The LCMS/LETS suite will make substantial progress on addressing a broad set of NASA’s strategic goals, and can fully address them on future lunar lander missions. Beyond NASA’s lunar exploration program, successful operation of the LCMS/LETS on the lunar surface will provide NASA with a flight-proven MS and LETS suite that can enable low cost, high performance mass spectrometry and/or radiation sensing on a wide variety of future planetary platforms including CubeSats, SmallSats, mini descent or drop probes, mini rovers and small landers, quadcopters, small balloons and ultralight aircraft. More »