Aiming for the Stars
One muggy Memphis night in the summer of '69, John Main sat in his parents' den watching crackling black and white images of Neil Armstrong and Buzz Aldrin on the moon. Ever since that historic evening, he's been a "space geek," says the UK professor of mechanical engineering and recent recipient of a prestigious National Science Foundation Faculty Early Career Development Award.
The four-year, $163,000 award provides Main support to shoot for the stars with his work on a novel space telescope. By reflecting images of distant stars with a colossal mirror, the telescope may allow astronomers to see galaxies as far removed in time as the Big Bang, the cataclysmic explosion that scientists believe was the dawn of our universe.
A mylar mockup of the mirror John Main is building resembles a miniature satellite dish made out of shiny metallic film.
"Because light takes time to travel from one place to another, the farther you can see in space, the farther you can see back in time," Main says. "If you want to see farther back, you've got to gather more light. With a bigger mirror, you can catch more photons."
The concept sounds simplethe new telescope, known as the Next Generation Space Telescope, reflects light into sensitive optics and transports images back to earth. The catch, however, is sizeat a kilometer in diameter, the mirror's girth would stretch across 11 football fields.
"To build one that large, we'll have to get over the constraint of structures we can carry in the cargo bay of the shuttle or similar launch vehicle," Main says. That's where his project, designing the mirror apparatus, comes in.
A mirror constructed out of a flexible film could be rolled up and stashed on board a launch vehicle. Once the vehicle is in orbit, the mirror would robotically deploy and unroll in space.
"The mirror we're designing has pretty much the consistency of Saran Wrap," Main says. "We're working to change it from a big piece of thin plastic into a precision primary mirror that can be used for world-class science."
The transformation may sound like something from a science-fiction novel, but it's based on sound mechanical principles. The thin plastic, a weave of electrically polarized molecules known as piezoelectric material, changes shape in the presence of an electrical field. Main envisions that an electron gun, connected to the material with a lightweight framework, would spatter the plastic film with electrons. The plastic would then mold itself into a parabolic shape that would reflect a celestial view far deeper into space than even the Hubble space telescope has delivered.
Main's project, like the Hubble project which culminated after 20 years of research by NASA and other scientists, will require time and intensive collaboration. He is now creating small composite mirrors as stepping stones to the ultimate project. A mylar mockup in his lab resembles a miniature satellite dish made out of shiny metallic film.
"It's kind of funstudents look at it and they get excitedit's not something that's divorced from the things they dream of," he says.
Main's enthusiasm is intensified by the award's long-term funding. "This is the kind of thing that faculty members need to be doing or at least trying. We don't necessarily have to win every proposal we write, but we've got to get in the game to bring more national recognition to the university. It also sets an example for the undergraduates whom we're teachingthere's no reason they can't set their sights on anything they want to accomplish."
Main, who earned his Ph.D. in mechanical engineering at Vanderbilt University, came to UK in 1997. His list of credentials includes a Summer Faculty Fellowship at the NASA Marshall Space Flight Center in Huntsville, Alabama, in 1995 and a NASA Advanced Concepts Research Program Fellowship for 1997-98.