The launch and deployment of picosatellites from the Stanford University OPAL microsatellite in February 2000 demonstrate the feasibility and practicability of a new age of space experimentation. Two of the six picosatellites deployed from OPAL were built by The Aerospace Corporation in El Segundo, CA and demonstrated new space testing of MEMS RF switches and intersatellite and ground communication with low power wireless radios. These picosatellites weighting less than one kilogram with dimensions of 4x3x1 inch were built as test platforms for DARPA and were constructed and delivered for flight in less than nine months. From this experience, a new generation of picosats called CubeSat is being developed by a number of organizations and universities to accelerate opportunities with small, low construction cost, low launch cost space experiment platforms. California Polytechnic State University at San Luis Obispo, CA is developing launcher tubes that can be part of a satellite or attached to any orbiting platform to launch from 1-3 CubeSats per tube. These tubes will contain CubeSats of 1-2 kilograms weight and approximately 4-inch cube shape. This size as compared to the picosatellites launched on OPAL provide better surfaces for practical solar power generation, physical size for components and a shape that provides better space thermal stability. A consortium of potential CubeSat developers is now wide ranging with universities from Japan, New Zealand, the US, amateur radio clubs and industry participants. Potential launch opportunities exist with the Russian Dnepr (SS-18) about twice/year, with the OSP (Minotaur) every 18 months and possible 100 km altitude orbits from the second stage of Delta launches. This paper will review the OPAL picosatellite launch and performance, the launcher being built for the CubeSat, the development and payloads of CubeSat developers and cost and timing of launch opportunities.

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CubeSat: A New Generation of Picosatellite for Education and Industry Low-Cost Space Experimentation

Thruster Options for Microspacecraft: A Review and Evaluation of State-of-the-Art and Emerging Technologies

Stanford University and California Polytechnic State University have combined efforts to develop a means of launching small picosatellites called CubeSat. The CubeSat is a 10cm cube weighting 1 kg or less. The launching system developed will provide launches for three satellites in one launcher tube. The first mission for this launcher will be to fly six tubes to launch as many as 24 CubeSats in May 2002 on a Kosmotras, Dnepr ELV from Bikinour, Ukraine. Stanford and Cal Poly are providing active technical support for the CubeSat developers, which are mostly universities. Once the CubeSats have been developed by the universities and other customers, they will be sent to Cal Poly for final testing, insertion into the launcher then shipped to One Stop Satellite Solutions in Ogden, Utah where they will be mounted on the OSSS Multiple Payload Adapter, then sent to Russia and integrated onto the Dnepr. TABLE OF CONTENTS

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CubeSat: The Development and Launch Support Infrastructure for Eighteen Different Satellite Customers on One Launch

An overview of mems-based micropropulsion developments at jpl

Hybrid optimization for multiple-impulse reconfiguration trajectories of satellite formation flying

Spacecraft formation flying is a proposed technology with vast performance implications ranging from enhanced mission capabilities to radical reductions in operations cost. To explore this concept and to enable its realization, Stanford University and Santa Clara University have initiated development of a simple, low cost, two-satellite mission known as Emerald. The Emerald mission has four primary goals. First, it will verify component-level technologies necessary for advanced formation flying missions. This will include the test of low-power Global Positioning System (GPS) receivers for position sensing, simple radio modems for inter-satellite communication, and experimental microthrusters for position control. Second, it will integrate the operation of these payloads in order to experiment with simple closed loop relative position control. Third, it will validate the formation flying concept by using coarse on-orbit relative position sensing and control to improve a scientific investigation of lightning-induced atmospheric phenomena. Fourth, it will extend low-cost satellite development techniques critical to fielding multi-spacecraft fleets. The bus design for the Emerald spacecraft will be based on Stanford's Satellite Quick Research Testbed (SQUIRT) microsatellite design. This consists of a 15 kilogram structure, a modular 12 inch tall by 18 inch diameter hexagonal configuration, a 68332-based flight processor, a single battery, solar panels, and simple attitude and thermal control. A Space Shuttle launch in 2001 has been tentatively selected for the launch of this mission. Emerald will be developed as part of the Defense Advanced Research Projects Agency (DARPA) and Air Force Office of Scientific Research (AFOSR) University Nanosatellite Program, an element of AFOSR's TechSat 21 Program. This paper discusses the Emerald mission objectives and approach, the conceptual design of the Emerald spacecraft, and the programmatic structure of this joint Stanford University-Santa Clara University project.

Emerald: A low-cost spacecraft mission for validating formation flying technologies

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The Satellite Quick Research Testbed (SQUIRT) Program

Distributed space systems are often cited as a means of enabling vast performance increases ranging from enhanced mission capabilities to radical reductions in operations cost. To explore this concept, Stanford University and Santa Clara University have initiated development of a simple, low cost, two-satellite mission known as Emerald. The Emerald mission has several on-orbit goals. First, it will verify an array of component-level technologies necessary for enabling highly capable and robust distributed space systems. Second, it will combine these technologies to experiment with simple closed loop relative positioning, distributed control, and autonomous operation. Third, it will validate the distributed space system concept by assessing how these capabilities improve a baseline scientific investigation involving lightning-induced atmospheric phenomena. The Emerald bus design is based on a heritage Stanford University design, a 15-kilogram, modular hexagonal vehicle relying heavily on commercial off-the-shelf components. Emerald is being funded through the AFOSR/DARPA University Nanosatellite Program, and a Space Shuttle launch in 2001 is being planned. This paper will discuss the Emerald team’s programmatic and on-orbit objectives, the conceptual design of the Emerald spacecraft, and the development approach adopted by the university team.

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Emerald: An Experimental Mission in Robust Distributed Space Systems

As part of its research program in spacecraft operations, Stanford University's Space Systems Development Laboratory (SSDL) is developing a ground station control system to support advanced command and telemetry operations. Known as Mercury, this control system provides direct human console control, remote human tele-operation, and script/program based autonomous control. Each of these modes supports the ability to configure and monitor station equipment as well as to conduct command and telemetry operations with spacecraft. The Mercury system is being implemented on SSDL's OSCAR-class amateur radio ground station. Mercury is currently being used to operationally test two SSDL microsatellites being prepared for launch in 1999. This paper describes the design and operation of the Mercury system, its implementation in the SSDL OSCAR station, its use to conduct mission operations with SSDL microsatellites, and its role in SSDL's multi-satellite, multiground station mission operations architecture.

C.A. Kitts

Papers

Emerald: A low-cost spacecraft mission for validating formation flying technologies

The Satellite Quick Research Testbed (SQUIRT) Program

Emerald: An Experimental Mission in Robust Distributed Space Systems

Mercury: a satellite ground station control system

Mercury: a satellite ground station control system