Collins Decodes Problems, Keeping Galileo Safe in Outer Space By Ken Keatley Twice--once before launch, once millions of miles from earth-- Oliver Collins has rescued the $1.3 billion deep space probe Galileo from mission-threatening peril. "I'm not quite sure I'd say I'm a troubleshooter for Galileo," said Dr. Collins, 30, an assistant professor of electrical and computer engineering in the School of Engineering. "It's gotten into trouble at interesting times for me." Dr. Collins--whose erudite manner and keen intellect mask his unlikely avocation as a steed-riding, Wyoming-roaming cowboy- -has been blessed with immaculate timing. Each time he finds a solution, there is a problem just waiting for it. "It's extremely rare, even in engineering, for people to be working on an academic problem and then to have somebody actually build a machine based on the results," Dr. Collins said. "The probability is less than once in a lifetime, so it's very nice to have it happen twice." His first once-in-a-lifetime experience took place in 1988, while he was working on a Ph.D. in electrical engineering at the California Institute of Technology. Delayed after the 1986 explosion of the space shuttle Challenger, Galileo was again threatened. Because of Challenger-inspired changes, the upper stage rocket that would propel Galileo on its more than 2 billion-mile mission was not as powerful as originally planned, and the change in orbit would have produced a decrease in information transmission capability. As a result, Jet Propulsion Laboratory scientists had to find a way to get the radioisotope thermoelectric generators that power Galileo to transmit the data collected from Jupiter by using less power. It required an upgrade to the spacecraft's communications coding system, and just such an upgrade--a new convolutional decoder--was the subject of Dr. Collins' thesis project. "There was a fundamental problem that had kept people from implementing these particular codes, and I was able to solve that problem," he explained. "So I got a chance to see what I worked on for my thesis put into use, which was really quite a lot of fun." Galileo was launched on Oct. 18, 1989, deployed from the space shuttle Atlantis on the first leg of a six-year journey that will ultimately probe the secrets of the planet Jupiter. But 18 months into the mission, Galileo was again plagued with a crisis that could have prevented the data being recorded from being transmitted to Earth. Prior to a flyby of the asteroid Gaspra, Galileo's fragile, umbrella-like, high-gain antenna became stuck, and unable to unfurl properly. JPL scientists determined the cause of the problem_some of the graphite ribs in the antenna were jammed in the closed position_but not a way to fix it. Quite conveniently, Dr. Collins, by then a young faculty member at Hopkins, was working on a new coding scheme--partly funded by JPL--called determinate state convolutional codes, that would further boost transmission efficiency, even with a balky antenna. "Just about the time that I had some results and was ready to start thinking about writing a paper on it, Galileo's antenna didn't open," he recalled. "I kept getting progressively more urgent phone calls from JPL: 'Could you please send us the paper, now?' "I got it to them in time, and it turned out to be the best solution for upgrading the spacecraft's software," he said. In April Dr. Collins won the Marconi Young Scientist Award for his research on determinate state convolutional codes and long constraint length decoders. Honored in Washington at a black-tie dinner, he received an engraved bronze medal and a $10,000 award from the Marconi Foundation. Also this year, his research titled "The Subtleties and Intricacies of Building a Constraint Length 15 Convolutional Decoder" garnered him the 1994 Browder J. Thompson Memorial Prize Paper Award from the Institute of Electrical and Electronics Engineers. The award was presented June 30 during the IEEE International Symposium on Information Theory in Tron-heim, Norway. The prize included a $1,000 award. The Thompson Prize puts the Department of Electrical and Computer Engineering in select company, as only a handful of universities have won it more than twice. Former department chair William Huggins, now professor emeritus, was a Thompson Prize honoree in the 1940s. Dr. Collins continues to conduct research in new coding techniques and means for implementing them, with the end result of achieving very large scale, low cost data collection and improvements in cellular telephone and terrestrial satellite communications. "In a sense, I've been spoiled," Dr. Collins said. "It is ridiculously improbable to have two things actually used in a large scale way in the course of four or five years. Now, the challenge is to try to come up with something else."
Go to Gazette Homepage