After Eros - Future Multiple-Target Dedicated Asteroid Missions
R. L. S. Taylor; D. G. Fearn (2003), JBIS, 56, 2-32Refcode
: Asteroids, Centaurs, cluster mothership, electric propulsion, ion-thrusters, Kuiper Belt, main belt, meteorites, multiple-target missions, nuclear reactors, poly-able spacecraft, radio isotope power generators, solar concentrators, spectral classification, trajectory profiles.Abstract:
This paper reviews briefly the results of space-probe asteroid-encounters and their implications for the astro- nomical study of these important bodies, with particular reference to the NEAR-Shoemaker (NS) Mission. NS was the first space project dedicated exclusively to the study, from close orbit, of an asteroid; the S(IV)-type 433 Eros. It also achieved the first, originally unplanned, soft landing on an asteroid. In addition to studying the physical, structural and dynamic characteristics of Eros, the NS mission sought to resolve the question of the inexact match between the remote and laboratory reflectance spectra of asteroids and meteorites - that is of presumed source and sample materials. Although brilliantly successful in collecting comprehensive data char- acterising the physical nature of Eros, the spectra obtained by NEAR do not allow the unequivocal resolution of the important source/sample question. More recently, NASA announced (21 December 2001) a new Discovery- class mission named `DAWN`, that is scheduled for launch in 2006. Dawn will rendezvous with and orbit sequentially the two largest main belt asteroids 4 Vesta and 1 Ceres, each for a period of about 11 months in a mission lasting a total of nine years. Although important targets in terms of understanding the early differentia- tion and evolution of partly evolved proto-planets, neither of these large bodies, with estimated diameters of 528 and 932 km respectively, is representative of undifferentiated primordial asteroid states or materials. In this paper, it is suggested that a programme of relatively low cost, multiple-target, missions to explore asteroids within the main belt is both technologically possible and scientifically necessary. Determining the nature and origin of asteroids is of high significance in developing a fundamental understanding of the formation of star/ planet systems in general and the solar system in particular. Multiple-target missions are suggested as a cost- effective means of conducting the detailed exploration of a significant number of S, C, and other types of main belt asteroids - and ultimately for the study of the far distant Kuiper-Belt objects.
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