Polar Regolith Environment Molecular Impact Simulation Experiment (PREMISE), 15-R8241
Edward L. Patrick
Gregory P. Miller
Inclusive Dates: 07/01/11 – Current
Background — The need for this project was based upon recent discoveries of volatiles sequestered at and near the lunar poles. If cometary impacts are the source of these sequestered volatiles, what local pressures, exposure times and temperatures are necessary to produce a detectable inventory of compounds detectable by a landed mass spectrometer instrument?
Approach — The main objective of this work is to produce a laboratory simulation of the lunar surface conditions in a chamber containing a sample cup containing a measured quantity of JSC-1A lunar soil simulant. The soil sample cup is cooled to cryogenic temperatures and selected gases leaked into the chamber over a fixed period of time. After the period of time allotted, the cooling will be reversed and the temperature of the soil sample increased to a level above that typical of lunar noon temperatures. A thermogram of the evolving gas will be recorded using a residual gas analyzer and ionization gauge. To characterize the experimental setup, the experiment will first be performed with nitrogen both with and without lunar simulant present, before moving on to the important volatiles, water vapor and carbon dioxide. After the basic volatile gas entrapment experiments are completed, a UV source, ion source and mechanical rod will be used to disturb the gas-laden soil simulant for the purpose of establishing the best combination of soil preparation techniques for the prototype inlet of a landed mass spectrometer. An existing cryotrap inlet system (CIS) will be used as a means to collect and store volatiles evolved by the three above-described methods for probing the lunar soil.
Accomplishments — To date, a prototype soil sample chamber has been designed and assembled. A solid copper soil sample cup has also been designed and fabricated and is awaiting assembly after fitting with thermocouples and temperature loggers has been completed.