The Lunar Dust EXperiment LDEX for the Lunar

The Lunar Dust EXperiment (LDEX) for the Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission Z. Sternovsky, M. Horányi, E Grün, R Srama*, M. Lankton and D. Gathright LASP, University of Colorado at Boulder Colorado Center for Lunar Dust and Atmospheric Studies, (*) Max-Planck-Institute for Nuclear Physics, Heidelberg, Germany NLSI meeting, NASA Ames, July 2009

LADEE motivation LADEE: Lunar Atmosphere and Dust Environment Explorer Remote observations of the Na exosphere (Potter & Morgan, 1998) • Identified species: 40 Ar, 36 Ar, 222 Rb, He, Na, K C, N, O, CO 2, CH 4 • Measurements are not detailed enough • Accurate composition measurements BEFORE disturbing by increased robotic and human activity Is dust really lofting from the lunar surface? NLSI meeting, NASA Ames, July 2009

LADEE Payload Neutral Mass Spectrometer (NMS) UV Spectrometer (UVS) MSL/SAM Heritage LCROSS heritage SMD - Directed instrument In situ measurement of exospheric species Dust and exosphere measurements P. Mahaffy NASA GSFC (Directed – SMD) A. Colaprete NASA ARC 300 Dalton range/unit mass resolution (Directed – SMD) Lunar Dust EXperiment (LDEX) Lunar Laser Com Demo (LLCD) Impact ionization dust detector Technology demonstration High Data Rate Optical Comm HEOS 2, Galileo, Ulysses and Cassini Heritage D. Boroson MIT-LL M. Horányi LASP (Directed – SOMD) (Competed – SMD) SMD - Competed instrument 51 -622 Mbps NLSI meeting, NASA Ames, July 2009

The dust environment 2 dust sources: a) Electrostatic lofting near the terminator region b) Secondary ejecta from micrometeoroid bombardment Lofted dust The expected dust density at 50 km altitude as a function of dust size (M. Horanyi) Detectable single impact events Impact ejecta NLSI meeting, NASA Ames, July 2009

LDEX: operation principle Detectors: - target charge sensitive amp (e-) - Microchannel plate (ions) Integrated charge from particle <0. 25 micron Impact ionization Q/m ≈ 2 C/kg (3, 000 e- for r = 0. 25 micron) NLSI meeting, NASA Ames, July 2009

LDEX: Ion optics design Dust Target A Gnd Dust Ion Paths -1600 V Grid MCP -1100 V Plate Dust NLSI meeting, NASA Ames, July 2009 Hemi Grid -200 V

Lunar Trajectory Use of Phasing Loops compensates for dispersions from Minotaur V NLSI meeting, NASA Ames, July 2009

UV environment LADEE orbit UV reflection from Moon Low UV backgrnd. No science UV from the sun is prohibitive for science UC reflected from the Moon drives: - Instrument geometry - Materials used - Finishes and coatings NLSI meeting, NASA Ames, July 2009

Summary and conclusions • LDEX is on schedule for a lunch on Friday 5/25/2012 • Calibration at both in Heidelberg and CCLDAS NLSI meeting, NASA Ames, July 2009