http://smartech.gatech.edu/handle/1853/8011 Search the Channel search http://smartech.gatech.edu/simple-search http://smartech.gatech.edu/handle/1853/8028 Title: Aerobraking Cost/Risk Decisions <br/> <br/>Authors: Spencer, David A.; Tolson, Robert <br/> <br/>Abstract: Three missions have successfully used aerobraking to reduce the spacecraft orbit period and achieve the desired orbit geometry. A fourth, Mars Reconnaissance Orbiter, will employ aerobraking following its orbit insertion in March, 2006. The propellant mass reductions enabled by the aerobraking technique allow the use of smaller launch systems, which translate to significant savings in launch costs for flight projects. However, there is a significant increase in mission risk associated with the use of aerobraking. Flying a spacecraft through a planetary atmosphere hundreds of times during months of aroundthe- clock operations places the spacecraft in harm’s way, and is extraordinarily demanding on the flight team. There is a cost/risk trade that must be evaluated when a project is choosing between a mission baseline that includes aerobraking, or selecting a larger launch vehicle to enable purely propulsive orbit insertion. This paper provides a brief history of past and future aerobraking missions, describes the aerobraking technique, summarizes the costs associated with aerobraking, and concludes with a suggested methodology for evaluating the cost/risk trade when selecting the aerobraking approach. <br/> <br/>Description: This conference features the work of authors from: Georgia Tech’s Space Systems Design Lab, Aerospace Systems Design Lab, School of Aerospace Engineering, Georgia Tech Research Institute; NASA’s Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, Langley Research Center; and other aerospace industry and academic institutions http://smartech.gatech.edu/handle/1853/8029 Title: Ground System for the Solar Dynamics Observatory (SDO) Mission Observatory Mission <br/> <br/>Authors: Tann, Hun K.; Pages, Raymond J.; Silva, Christopher J. <br/> <br/>Abstract: NASA's Goddard Space Flight Center (GSFC) has recently completed its Critical Design Review (CDR) of a new dual Ka and S-band ground system for the Solar Dynamics Observatory (SDO) Mission. SDO, the flagship mission under the new Living with a Star Program Office, is one of GSFC's most recent large-scale in-house missions. The observatory is scheduled for launch in August 2008 from the Kennedy Space Center aboard an Atlas-5 expendable launch vehicle. Unique to this mission is an extremely challenging science data capture requirement. The mission is required to capture 95% of all observation opportunities with a completeness of 99.99%. Due to the continuous, high volume (150 Mbps) science data rate, no on-board storage of science data will be implemented on this mission. With the observatory placed in a geo-synchronous orbit at 36,000 kilometers within view of dedicated ground stations, the ground system will in effect implement a “real-time” science data pipeline with appropriate data accounting, data storage, data distribution, data recovery, and automated system failure detection and correction to keep the science data flowing continuously to three separate Science Operations Centers (SOCs). Data storage rates of ~ 42 Tera-bytes per month are expected. The Mission Operations Center (MOC) will be based at GSFC and is designed to be highly automated. Three SOCs will share in the observatory operations, each operating their own instrument. Remote operations of a multi-antenna ground station in White Sands, New Mexico from the MOC is part of the design baseline. <br/> <br/>Description: This conference features the work of authors from: Georgia Tech’s Space Systems Design Lab, Aerospace Systems Design Lab, School of Aerospace Engineering, Georgia Tech Research Institute; NASA’s Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, Langley Research Center; and other aerospace industry and academic institutions http://smartech.gatech.edu/handle/1853/8030 Title: DIRE - Dactyl-Ida Rendezvous Experiment <br/> <br/>Authors: Pengelly, Stan; Adams, J. Brian; Platt, Donald <br/> <br/>Abstract: The purpose of this paper is to discuss, at the system level, a theoretical spacecraft and mission named DIRE (Dactyl-Ida Rendezvous Experiment). The spacecraft will travel to the asteroid pair Dactyl and Ida, which is approximately 3 AU from the Sun, to achieve the following mission objectives: • Measure the magnetic fields around the asteroid pair and each object individually. • Take multispectral images at various altitudes to determine surface regolith composition and distribution. • Using ground penetrating radar, attempt to discern the hidden structure of Ida and Dactyl and answer this question: are asteroids actually many rocks loosely coalesced into a single body and held together by gravity, rather than a huge monolith? • Descend autonomously to each asteroid and retrieve samples of regolith, using micropropulsion systems. Analysis of regolith will then be performed with on board systems. • Near the end of the mission launch a ground-penetrating explosive into Dactyl in an attempt to split into its subparts. The purpose here is to develop a technique for neutralizing a possible Earth damaging asteroid by separating it into smaller, less dangerous objects. DIRE will then make radar measurements of the ensuing asteroid breakup and determine if and how the asteroid re-coalesces. • Get a first ever look at material from within an asteroid, after the explosive splits Dactyl. This mission uses features of previous spacecraft missions and adds a never before attempted explosive penetrator to probe deeply and precisely into an asteroid. Thus, this mission will add to deep space object science and perhaps provide a way for mankind to defend itself against them. <br/> <br/>Description: This conference features the work of authors from: Georgia Tech’s Space Systems Design Lab, Aerospace Systems Design Lab, School of Aerospace Engineering, Georgia Tech Research Institute; NASA’s Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, Langley Research Center; and other aerospace industry and academic institutions http://smartech.gatech.edu/handle/1853/8031 Title: Impactor Spacecraft Encounter Sequence Design for the Deep Impact Mission <br/> <br/>Authors: Kubitschek, Daniel G. <br/> <br/>Abstract: On July 4, 2005, another first in space exploration was achieved. NASA’s Deep Impact spacecraft (s/c) released a small, 350 kg Impactor s/c designed to target comet Tempel 1, estimated to be 14 km x 5 km x 5 km in size at the time of release. With a closing speed of approximately 10.3 km/s, the Impactor s/c autonomously guided itself to impact and captured 40 cm resolution images, the highest resolution images ever of the surface of a cometary nucleus, just moments before the collision. The objective of the Impactor s/c was to impact in an illuminated area viewable from the Flyby s/c. This paper describes the Impactor encounter sequence design, execution and contingency planning that contributed to the successful outcome in which all objectives were met. <br/> <br/>Description: This conference features the work of authors from: Georgia Tech’s Space Systems Design Lab, Aerospace Systems Design Lab, School of Aerospace Engineering, Georgia Tech Research Institute; NASA’s Jet Propulsion Laboratory, Marshall Space Flight Center, Goddard Space Flight Center, Langley Research Center; and other aerospace industry and academic institutions