A VERY-LOW COST GROUND SYSTEM FOR A MICRO-SATELLITE MISSION

This paper describes the ground system currently being developed for w hat is thought to be a unique mission being flown in 1998. The main mi ssion in question is called BADR-B (Urdu for Full Moon) and is a Pakis tan mini-satellite designed to test out certain technologies and scien tific instruments. BADR-B is a gravity-gradient stabilised spacecraft, and as such it incorporates a gravity-gradient boom for attitude cont rol. The unique feature of this mission, however, is that the normal g ravity-gradient tip mass al the end of the boom has been replaced by a n autonomous micro-satellite. This consists of two scientific instrume nts (one for measurement of atomic oxygen, one for detection of small particulated debris) with completely self-contained power supply and d ata transmission. To transmit its data to the ground, the micro-satell ite forwards its data remotely by an optical/rf link to the mini-satel lite, and thereafter it is downlinked to one of two ground stations, t hese being at Lahore, Pakistan and at the Rutherford Appleton Laborato ry (RAL), Chilton, England. In order to keep costs to an absolute mini mum, the ground system at RAL for the micro-satellite is being designe d with autonomy in mind, and the re-use of much existing hardware and software. The cost-efficient development of the hardware, software and operations is described in this paper. Copyright (C) 1996 Elsevier Sc ience Ltd