NLSI meeting, NASA Ames, July 2009

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

Remote observations of the Na exosphere (Potter & Morgan, 1998)

• Identified species: 40Ar, 36Ar, 222Rb, He, Na, K C, N, O, CO2, CH4• Measurements are not detailed enough• Accurate composition measurements BEFORE disturbing by increased robotic and human activity

Is dust really lofting from the lunar surface?

LADEE: Lunar Atmosphere and Dust Environment Explorer

NLSI meeting, NASA Ames, July 2009

60 cm

100 mm OpticalModule

Modems

Control

Electronics

Lunar Dust EXperiment (LDEX)Impact ionization dust detector

Neutral Mass Spectrometer (NMS)MSL/SAM Heritage

UV Spectrometer (UVS)LCROSS heritage

Lunar Laser Com Demo (LLCD) Technology demonstration

Dust and exosphere measurements

A. ColapreteNASA ARC(Directed – SMD)

In situ measurement of exospheric species

P. MahaffyNASA GSFC(Directed – SMD)

51-622 Mbps

300 Dalton range/unit mass resolution

HEOS 2, Galileo, Ulysses and Cassini Heritage

M. HorányiLASP(Competed – SMD)

High Data Rate Optical Comm

D. BorosonMIT-LL(Directed – SOMD)

LADEE Payload

SMD - Directed instrument

SMD - Directed instrument

SMD - Competed instrument

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

The expected dust density at 50 km altitude as a function of dust size (M. Horanyi)

Lofted dust

Impact ejecta

Detectable single impact events

NLSI meeting, NASA Ames, July 2009

LDEX: operation principle

Impact ionization

Q/m ≈ 2 C/kg

(3,000 e- for r = 0.25 micron)

Detectors: - target charge sensitive amp (e-) - Microchannel plate (ions)

Integrated charge from particle <0.25 micron

NLSI meeting, NASA Ames, July 2009

MCP-1100 V

Target A Gnd

Ion Paths

Hemi Grid-200 V

-1100 V Plate

-1600 V Grid

Dust

Dust

Dust

LDEX: Ion optics design

NLSI meeting, NASA Ames, July 2009

Lunar Trajectory

Use of Phasing Loops compensates for dispersions from Minotaur V

NLSI meeting, NASA Ames, July 2009

UV environment

No science

UV reflection from Moon

Low UV backgrnd.

LADEE orbit

UV from the sun is prohibitive for scienceUC 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