Jordin Kare represented Beam Power Challenge team LaserMotive. This talk follows talks by Leik Myrabo and Jordin himself on Laser Launch. This is all about "power beaming on a shoestring". LaserMotive was formed for the power beaming prize, and maybe more.
Jordin gave an overview of the prize and the prize's history.
He was interested in power beaming, and saw the 2006 contest with Tom Nugent and decided to go for it. He showed slides for the team members and sponsors. One member has a machine shop. One software team member got a "hamburger patty flow detector" contract based on LaserMotive work.
Jordin went over the basic rules of the 2007 challenge. They designed for much more than the rule minimum that year. Looking back, that may have been a mistake. Wind was a factor during the competition. They needed ~8000 watts of laser power going in to get the needed ~1000 watts. They used DILAS. You can't see the laser - you just see the burns. Jordin described the overall design, transmitter optics, transmitter design, and the beam pattern on solar cells. He showed a picture of the built system, and team members working on it. He discussed power supplies, cooling, and safety.
For the photovoltaic array, he covered the design goals and drivers (under 5 kg, 1m by 1m, etc). He showed the PV cells. They're gallium arsenide cells. They're about 40% efficient. They're not designed for much more than 1 sun equivalent. Boeing owns SpectraLab (Boeing is a LaserMotive partner) and got them to make specialized cells designed for 10 suns. These were 50-55% efficient.
Jordin described the system's thermal control. A picture of the cells shows custom wiring. Middle cells are the high-performance ones, and the others are tilted to get less "suns". He showed the climber. An automatic tracking system is video-based. Laser pointers shine on reflectors on the climber. 3M retrofeflective tape is on the vehicle. Jordin shows a picture of a 2-axis steering/turning mirror, and pictures of a testing stand. He also shows a test video from before the 2007 contest to show the system works.
He discusses similar issues to what John Carmack said: a 1-time only per year contest is a difficult way to run an R&D effort. He discussed weather and competitors at the contest. They had a confused time at the qualification climb. They were rebuilding the climber because they thought they were done qualifying. Because of that they weren't ready when they needed to be, and got caught by a simple problem.
He had some lessons learned: worry about simple things, test early and often in a working environment, system integration is important, and realize that a competition environment is tough. Nevertheless he's looking ahead to the next competition.
He discussed the future of power beaming aside from space elevators. For NASA, it could be remote power for rovers on the Moon or Mars, or power for a lunar base. For DARPA it could be satellite-to-satellite power. There could be air-to-air or ground-to-air applications, for example for the military. For the DoD it could be small solar power satellites in a space-to-air or space-to-ground configuration. For now, though, they're concentrating on the Beam Power prize.
To see more about this talk, check out Why Homeschool and RLV News. Also note that Jordin had another talk at Space Access '08 on Laser Launch. You can find out about the Laser Launch talk at RLV News and Why Homeschool. They also document a Laser Launch talk by Leik Myrabo (Why Homeschool link and RLV News link).