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From Ellipses to Gravity Assists
by Charley Kohlhase

This webcast begins with the simple notion of an ellipse, easily created by any young person, then moves on to Kepler's laws and the famous conic sections to slowly build a framework within which to understand how mission designers at JPL work out their special flight paths to the planets. In the early days of space exploration, Hohmann transfer ellipses were used to travel from the Earth to Mars and Venus. With the invention of gravity assist, journeys were soon made possible to the more distant planets, with the Voyager, Galileo, and Cassini missions being prime examples.

Trajectory Design and Gravity Assist Videos:

[Editor's note: these videos were originally made to be available via streaming video. The following links are to files recovered that were previously archived. As such, please excuse the quality of the video.]

  • Part 1 (QuickTime, 73.72 MB), Part 1 (MP4, 115.92 MB), Part 1 (Real Media, 8.36 MB)
  • Part 2 (QuickTime, 60.1 MB), Part 2 (MP4, 100.77 MB), Part 2 (Real Media, 7.28 MB)
  • Part 3 (QuickTime, 66.72 MB), Part 3 (MP4, 110.07 MB), Part 3 (Real Media, 7.95 MB)
  • Part 4 (QuickTime, 54.74 MB), Part 4 (MP4, 92.88 MB), Part 4 (Real Media, 6.72 MB)

Presentation:   From Ellipses to Gravity Assists

Presentation to accompany videos: Download (PDF, 438 KB)

  • Blend space exploration with reading and writing -- Reading, Writing & Rings!
  • Cassini Scientist for a Day -- Students get involved
  • Cassini Raw Images