A University of Maryland team of astronomers will lead a $40 million NASA effort to use a recycled spacecraft to study a set of planets outside our solar system and then fly the craft within 620 miles of a distant comet for a close look.

The Deep Impact spacecraft will survey the heavens around five stars that have Jupiter-size planets, looking for planets capable of supporting life.

That work will begin in January and last about six months.

The craft will then head toward a meeting with comet Hartley 2 in 2010; it will use its two telescopes and infrared spectrometer to study the half-mile-wide comet.

Hartley 2 was selected for the mission because its trajectory puts it within reach and because its small size and the amount of material it ejects make it worth probing, said Michael A'Hearn, the University of Maryland astronomer who is the mission's principal investigator.

The mission, known as EPOXI, will use the Deep Impact spacecraft that made international headlines in 2005 when A'Hearn's team launched a probe from it that smashed into Comet Tempel 1.

After Deep Impact's first mission was completed, the team began working to persuade NASA that the spacecraft was capable of continuing to explore space at a fraction of the cost of building and launching a new craft.

The mission will be made possible by recalibrating Deep Impact's instruments, A'Hearn said.

EPOXI stands for Extrasolar Planet Observation and Characterization and the Deep Impact Extended Investigation.

The mission will be operated through a partnership of the university, NASA's Goddard Space Flight Center in Greenbelt, NASA's Jet Propulsion Laboratory and Ball Aerospace & Technologies Corp.