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Past Conference Papers:
Responsive Missions - Communications
| Paper Number RS5-2007-4004: Responsive Spacecraft Bus Implementation for Unique HEO Missions Based on Standard Interfaces | |
| P.A. Stadter (Johns Hopkins University Applied Physics Laboratory), C.S. Schein (Johns Hopkins University Applied Physics Laboratory), M.T. Marley (Johns Hopkins University Applied Physics Laboratory), C.T. Apland (Johns Hopkins University Applied Physics Laboratory), R.E. Lee (Johns Hopkins University Applied Physics Laboratory), B.L. Kantsiper (Johns Hopkins University Applied Physics Laboratory), B.D. Williams (Johns Hopkins University of Applied Physics Laboratory), E.D. Schaefer (Johns Hopkins University of Applied Physics Laboratory), S.R. Vernon (Johns Hopkins University of Applied Physics Laboratory), P.D. Swartz (Johns Hopkins University of Applied Physics Laboratory), E.J. Finnegan (Johns Hopkins University of Applied Physics Laboratory), J. Chris Garner (Naval Research Laboratory) | |
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| Abstract: This paper will provide details of the implementation of an Operational Responsive Space spacecraft bus to be used by the TacSat-4 CommX mission in a highly elliptical orbit (HEO). Through this discussion, two primary themes of the RS5 conference will be addressed: applications that lend themselves to solution by small spacecraft in HEO orbits and implementation of a critical element of the overall mission within the context of responsive capabilities. Specifically addressed will be the challenge of developing a spacecraft bus as a platform designed to a set of defined interface standards, while faced with the unique requirements of a particular payload. This will include a discussion of the driving requirements for the bus to provide operations in the HEO orbital environment and the user applications that can take advantage of such a platform given candidate payloads. The paper will provide details on design and implementation decisions that were made to accommodate standards, and places where proposed standards were not able to be addressed for the particular implementation. The technical details included will provide insights into the bus implementation well after Critical Design Review, but prior to space vehicle Integration and Test, thus system designs will be mature and near completion. | |
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| Paper Number RS7-2009-3001: Leveraging the First ORS Mission into ORBCOMM and the Implications for Future ORS Missions | |
| Todd Mosher (Sierra Nevada Corporation Space Systems), H. ‘Lad’ Curtis (Sierra Nevada Corporation Space Systems) | |
| View/Download:Presentation | Paper | |
| Abstract: On December 16, 2006, Tacsat-2 launched from Wallops Island, Virginia atop a Minotaur rocket to become the first Operationally Responsive Space (ORS) Satellite. After one year of operation it went beyond its 6 months of design life to make several notable accomplishments. First, Tacsat-2 was launched in 36 months after both an orbit and launch vehicle change during System Integration and Test. Second, it demonstrated command uplink and image downlink to a mobile tactical ground unit, collected color and panchromatic images from space with less than 1 m resolution, and provided a unique ELINT sensor demonstration from space. Third, it was operated in a different way with commanding of the spacecraft via the Internet, on-board autonomous orbit maintenance software calculating the orbit and thruster firings, and on-board autonomous task planning and execution. This mission was enabled by a capable spacecraft that supported fourteen successful payloads/experiments on one 361 kg spacecraft for a 58% payload mass fraction. It also had several key technologies including on-board image processing, the first U.S. Hall Effect thruster flown in space with new data on in-situ performance, the demonstration of a low power transceiver, and a thin-film solar array deployment demonstration. It has been recognized by Aviation Week and Space Technology Magazine with its Small Company Product Breakthrough Award and the American Institute of Aeronautics and Astronautics with its Space Systems Award. The success of this program has been parlayed into the ORBCOMM replenishment program (OG-2). As outlined by ORBCOMM, the current order for 18 satellites with a possible option for 30 more is a proactive approach to replacing the currently flying constellation of 29 low-orbiting satellites that provide two-way messaging service. As stated publicly by ORBCOMM officials on December 4, 2007 ORBCOMM expects to pay about $6.3 million for each of the 18 satellites and to launch them between 2010 and 2012. The similarity of SNC’s response to these cost and schedule requirements to the goals of ORS is not a coincidence. In fact, if anything the programmatics are more aggressive than many of the ORS goals and as they are successfully accomplished they should cause ORS to revise the expectations of what is possible. MicroSat Systems also won one of the four ORS BAA-3 awards to study the next generation of ORS satellites that move beyond the Tacsats to have more operational capabilities. With its partners it has developed innovative strategies to make these satellites better respond to ORS requirements such as urgent needs with the ability to be built rapidly and ready for launch in a depot like operation. While this has required some new approaches, it also has been influenced by Tacsat-2 heritage and lessons learned as well as commercial practices that come out of the ORBCOMM program. In this paper, Sierra Nevada Space Systems (the new entity created through the merger of MicroSat Systems and SpaceDev) approach to learning from the first ORS mission, Tacsat-2, and parlaying this into the ORBCOMM program will be discussed. Similarities of the ORBCOMM single payload, low cost, launch-on-demand mission to ORS objectives will be discussed and the implications of what the success of the ORBCOMM program may have for future ORS missions will be projected. | |
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