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Abstract:

The Diviner Lunar Radiometer Experiment on NASA's Lunar Reconnaissance Orbiter will be the first instrument to systematically map the global thermal state of the Moon and its diurnal and seasonal variability. Diviner will measure reflected solar and emitted infrared radiation in nine spectral channels with wavelengths ranging from 0.3 to 400 microns. The resulting measurements will enable characterization of the lunar thermal environment, mapping surface properties such as thermal inertia, rock abundance and silicate mineralogy, and determination of the locations and temperatures of volatile cold traps in the lunar polar regions. © The author(s) 2009.

Abstract:

The Marco Polo mission has been selected by the European Space Agency (ESA) as a candidate for launch under the Cosmic Vision programme in -2017. The mission ultimately aims to understand the origins of the planets and even life itself, by returning a sample of material from a primitive asteroid, representative of the early Solar System. Particles on the surface of the asteroid are readily charged by photoelectric emission. Preliminary calculations suggest that photoelectric fields of tens of volts per metre are expected, and electrostatic transport, levitation, and even complete ejection from the asteroid's gravitational field seem likely for typical particles at the proposed candidate asteroids. The electrical and charged particle environment at the asteroid surface is therefore expected to be significant for sample selection and characterisation. The Asteroid Charge Experiment (ACE), comprising an electric field sensor to detect charged dust particles, and an electron spectrometer to measure both photoelectrons and electrons from the solar wind, is described here. ACE will also be able to determine the relative electrostatic potentials of the spacecraft and asteroid surface, which will quantify the electrical effects of the sampling process itself on the asteroid environment.