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Pojman, Joan

Publications and source records attributed to Pojman, Joan.

Cassini-Huygens maneuver automation for navigation

Many times during the Cassini-Huygens mission to Saturn, propulsive maneuvers must be spaced so closely together that there isn't enough time or workforce to execute the maneuver-related software manually, one subsystem at a time. Automation is required. Automating the maneuver design process has involved close cooperation between teams. We present the contribution from the Navigation system. In scope, this includes trajectory propagation and search, generation of ephemerides, general tasks such as email notification and file transfer, and presentation materials. The software has been used to help understand maneuver optimization results, Huygens probe delivery statistics, and Saturn ring-plane crossing geometry. The Maneuver Automation Software (MAS), developed for the Cassini-Huygens program enables frequent maneuvers by handling mundane tasks such as creation of deliverable files, file delivery, generation and transmission of email announcements, generation of presentation material and other supporting documentation. By hand, these tasks took up hours, if not days, of work for each maneuver. Automated, these tasks may be completed in under an hour. During the cruise trajectory the spacing of maneuvers was such that development of a maneuver design could span about a month, involving several other processes in addition to that described, above. Often, about the last five days of this process covered the generation of a final design using an updated orbit-determination estimate. To support the tour trajectory, the orbit determination data cut-off of five days before the maneuver needed to be reduced to approximately one day and the whole maneuver development process needed to be reduced to less than a week..

propulsion maneuvers

Cassini tour navigation strategy

The Cassini-Huygens spacecraft was launched on October 15, 1997 as a joint NASA/ESA mission to explore Saturn. After a 7 year cruise the spacecraft will enter orbit around Saturn on 1 July 2004 for a 4 year investigation of the Saturnian system. The Cassini Navigation Team is responsible for designing the reference trajectory and conducting operations to realize this design. This paper describes the strategy for achieving project requirements, the characteristics of the Cassini navigation challenge, and the underlying assumptions.

Saturn

Cassini tour navigation strategy

This paper describes the strategy for achieving project requirements, the characteristics of the Cassini navigation challenge, and the underlying assumptions.

Cassini