Fly Me To The Moon
Posted on Sunday, October 12, 2008
Just finished reading a great book written by Edward Belbruno on his design of advanced trajectories called "Weak Stability Boundary Trajectories". Trajectories that helped save several spacecraft stuck in Low Earth Orbit, like the Japanese Hiten spacecraft. He gives a beautiful description of how a theoretical mathematician enters the space industry (at JPL) and comes up with a highly innovative way to think about trajectory design and gravitational fields. Basically, it comes down to using the gravitational fields of the Earth and Moon to have a "ballistic capture" into Lunar orbit. One of the metaphors he uses is the wave surfer. Be too slow, and the wave passes you by. Be too fast, and the wave won't catch up with you. In Belbruno's case, he is talking about gravitational attraction (not exactly waves [at least, not it his case], but the metaphor still works to explain the idea). Brings back memories of 10 years ago when I was working as part of my thesis on a mission that was planned to take one of these fuel-efficient trajectories to the Moon (image above was my script to use onboard cameras to film the Earth during the 90-day Lunar transfer based on trajectory design by Robin Biesbroek, the green circle is the moon's orbit around the Earth). Beautiful to read how innovation in space exploration happens. And he even manages to bring Vincent van Gogh's Starry Night into his conceptual framework (podcast with Belbruno at The Edge).