Characterization of asteroid analogues by means of emission and reflectance spectroscopy in the 1- to 100-µm spectral range

Abstract

The last decades have seen a large number of missions targeting small bodies in the solar system. NASA, ESA and JAXA sent missions to different solar system small bodies (SSSB), and the Japan mission Hayabusa returned samples from the surface of the S-type asteroid Itokawa. JAXA launched in 2014 a follow-up mission (Hayabusa2) to collect a sample from carbonaceous (C-type) asteroid 1999 JU3 asteroid and bring it back to Earth. The NASA’s OSIRIS-REx mission will launch in September 2016 to explore the carbonaceous asteroid Bennu. Despite an already existing rich collection of reflectance and emissivity spectral libraries for asteroid analogues, those are mostly based on measurements in air for a spectral range covering the visible to the medium infrared (approximately, from 0.4 to 25 µm). To characterize minerals, rocks and meteorites suitable for being surface analogues for asteroids and SSSB in general, spectroscopic measurements are needed for a wider spectral range and in vacuum, conditions that more closely resemble those found on asteroid surfaces. To fill this gap we acquired spectral measurements over a large spectral range (1–100 µm) for several meteorites and other analogues at the Planetary Emissivity Laboratory of the German Aerospace Center in Berlin. Those data provide more direct analogues for asteroid surfaces and expand our existing database of emissivity and reflectance measurements.