The Hera mission: multiple near-earth asteroid sample return

The NEAR mission was a spectacular rehearsal for one of the most exciting and scientifically rewarding missions of the next decade, sample return from near-Earth asteroids. A unique source of information about the early solar system, the formation of the planets, and the connection between stars and our Sun, are meteorites and asteroids. Yet, studies of both are hindered by a lack of unequivocal and detailed information linking the two. Meteorites are rock samples of unknown provenance. We have no information about the geological context of their source. They are also highly non-representative sampling of primitive solar system material because the terrestrial meteorite population is dominated by the ejecta of stochastic impacts and because the atmosphere filters out all but the toughest rocks. Without sample return, asteroids are not amenable to the depth and breadth of techniques available in the laboratory, yet the NEAR images indicate that there are many processes occurring on asteroids – or that could have occurred in the past – that we must understand if the meteorite data are ever to yield a clear image of early solar system processes. Technical developments of the last few years and the discovery of large numbers of NEAs mean that sample return is now within small mission capability. A team of about 20 scientists and engineers from all relevant subject fields are now assembling a mission called Hera. This paper reviews the mission as of fall 2002. 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.