Aeneas -- Colony I Meets Three-Axis Pointing

A dedicated satellite mission is currently under development at the USC Space Engineering Research Center. Named “Aeneas,” (after the Trojan warrior who personifies duty and courage) the cubesat will be used to track cargo containers worldwide. To accomplish this feat, the satellite must maintain a 2-degree-accuracy surface track – the first of its kind in cubesat technology. This paper describes the requirements, design, implementation and tests to date in the areas of: flight dynamics, flight software, deployable spacecraft antenna, store-and-forward software, custom flight processor including MEMS gyroscopes, Doppler-based orbit determination enhancement and mobile ground station dish with helical feedhorn. Details are provided about the attitude control system and communications. INTRODUCTION AND BACKGROUND Continual advances in micro-electronics enable more to be done with less. Today’s gadgets are smaller in size, lower in weight and consume less in power than their counterparts only a few years ago. This truism enables progress across many industries, and perhaps none so much as in cubesat technology. As the relaxation of constraints is allowing more performance to be packed into each cubic centimeter, nanosatellites are rapidly gaining the capability to address fundamentally important missions. 1 Recognizing this trend, the USC Astronautics Department and the Information Sciences Institute (ISI) jointly created the Space Engineering Research Center (SERC) a fast-paced learning environment pairing students with industry experts to push the envelope of nanosatellite technology. SERC’s current satellite program is Aeneas, which modifies a 3U (30x10x10cm) National Reconnaissance Office (NRO) specified Colony I Cubesat bus to address a research thrust of the Department of Homeland Security (DHS). The delivery of Aeneas is scheduled for December of 2011 and the flight is manifested for June of 2012. It contains two payloads. The primary payload speaks to a mission with global reach: tracking cargo containers over the open ocean with a 1-watt WiFi-like transceiver. A current tracking system for cargo containers, designed by our primary payload provider iControl Inc., is capable of identifying the container within a mile from shore, but loses all contact for the majority of the openwater journey. For both government and nongovernment entities, the ability to track containers in transit is highly valued. This mission uses a custombuilt deployable mesh antenna, and stretches the attitude control and power generation capabilities of the Colony I bus to its limits. The secondary payload is an experimental, nextgeneration, radiation-hardened flight processor. The result of many government-funded research initiatives, this ITAR-controlled processor is at risk of staying in the “unholy valley” between research and development. On Aeneas, the processor will be space-qualified by performing self-diagnostic checks and reporting the results back to the ground. We hope that by raising the technology readiness level (TRL) we can provide a path to service for this highperformance chip. In this paper we will discuss the design work and fabrication supporting the primary payload: namely, three-axis pointing and the deployable antenna. We begin by describing the entire cubesat, focusing on those components that will serve a critical role in the success of the mission.