April 15, 2013

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Colorful Trajectories

video from KickStarter

When I was an undergrad my most amazing calculus prof was also a concert pianist. My friend Bill Hartmann is both a creative planetary scientist and skilled artist specializing in visualizing the processes of planetary formation. The relation between science and the arts is real but perhaps somewhat rare. This excerpt from a film in progress traces how a mathematician used painting to subconsciously explore unique trajectories to the Moon. Dr. Ed Belbruno had been a JPL scientist studying how to optimize trajectories to Jupiter for the Galileo mission when he started musing about trajectories that don't rely on the Holmann transfer. Traditionally, to go from being in the orbit of one planetary body to another, a rocket would follow a trajectory that was tangent to each planetary body's orbit when the planet was at that point. The film points out something I didn't appreciate, that the Holmann transfer requires expending a significant amount of energy to slow down to go in orbit around the destination world. Fuel for retrofiring is very expensive so that trajectory is costly. Belbruno discovered a family of round-about low energy trajectories that don't require deceleration at the target world - his method was used to rescue the Japanese Hiten probe that was launched into the wrong orbit in 1990. In addition, SMART-1 and GRAIL used similar orbits to reach the Moon.

Chuck Wood

Related Links

Yesterday's LPOD: Don't Hold the Olive

Tomorrow's LPOD: Milk for the Moon


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