Attitude Determination and Control for the Multi-Mission Space Payload Platform (SPP)

The first artificial satellite, Sputnik, was a "smallsat" of sort with its 58 cm. diameter and mass of just under 84 kg. Since then, design trends have produced progressively larger spacecraft tracking the launch vehicle throw capabilities. This approach, however, is being challenged today and, although large satellites will continue to meet global requirements cost effectively, there is a need to accommodate specific payloads with smaller spacecraft buses. The economy of scale that called for larger satellites in the past, is now focusing on a multi-mission design approach. A general purpose spacecraft bus can be designed to support a wide range of payloads: meteorological, surveillance, communication, and scientific. General Electric Astro Space has developed such a reliable and cost effective vehicle, the Space Payload Platform (Photo 1), with a common core bus weighing 130 kg. (dry weight), available in both spin-stabilized and three-axis stabilized configurations. Compatible with both Air Launch Vehicle (ALV-Pegasus) and Standard Small Launch Vehicle (SSLV-Taurus), the SPP allows up to a 300 kg, 260 Watt payload to be injected directly into a low altitude circular or elliptic orbit. This basic capability can be augmented by an on-board hydrazine propulsion system to achieve, correct, and/or maintain higher altitude orbits. To accommodate these various programs, a flexible Attitude Determination and Control System (ADACS) has been implemented such that only a minimum of alterations are required for different missions. In this paper, we shall explore ADACS design approach for several configuration options.