Inside Iowa State

October 7, 2005

Controlling a spacecraft to Jupiter's icy moons

by Mike Krapfl

The challenge is about as big as Jupiter, our solar system's biggest planet:

How do you control a flexible spacecraft that's up to 200 feet long, will take seven years to get to its deep-space destination and needs pinpoint control to move it and its science payload from moon to moon?

Atul Kelkar, a professor of mechanical engineering, is part of the team that's been addressing that problem for the past two years.

And although NASA has suspended that proposed mission, Kelkar and other team members think their technology will be launched into space one day.

The team has been working on a proposed Jupiter Icy Moons Orbiter, a part of the National Aeronautics and Space Administration's Prometheus project. It would be powered and propelled by a nuclear reactor and electric ion engines. It would carry instruments to study three of Jupiter's moons: Callisto, Ganymede and Europa. It would look for signs of life-supporting water, thermal energy and organic chemicals.

Kelkar joined researchers from NASA's Ames Research Center, Moffett Field, Calif., and the Jet Propulsion Laboratory in Pasadena, Calif. The team has completed fundamental engineering work and simulations to establish the technical specifications for the spacecraft's control system and structural design. NASA has supported Kelkar's work on the project with $392,000 in research grants.

Don Soloway, a research scientist at the Ames Research Center, said Kelkar's work has been instrumental to the team. That's because Kelkar worked on a NASA project to design a control system for large space structures back in the 1980s. It turns out very few engineers have that background. And Soloway said that project's technology applied directly to the proposed Jupiter orbiter.

Ask about the Jupiter project and Kelkar turns to his computer and calls up images of the spacecraft, illustrations showing flexibility and vibration tests of spacecraft parts and charts detailing simulations of the spacecraft's performance.

And from what he can see of the Jupiter Icy Moons Orbiter mission from his office at Iowa State, Kelkar said the project is technically challenging, but certainly possible.

"I don't have doubt -- with the past history and experience we have -- that this can go," he said. "The problem is the commitment of Congress to keep a project alive for so many years."

Kelkar has been involved with NASA projects since he was a doctoral student at Old Dominion University, Norfolk, Va., where he researched the control of flexible space structures. He worked as a postdoctoral research associate at NASA's Langley Research Center, Hampton, Va. (1994-96).

Mechanical engineering professor Atul Kelkar is on a team working on a control system for Jupiter-bound spacecraft.