Pluto Power

The prospects of sending a spacecraft to Pluto look much better now than they did a year or so ago. In fall 2000, NASA stopped work on its Pluto-Kuiper Express mission because of mounting costs (see Physics Today, November 2000, page 45 ). A few months later, the agency opened the mission to competition, stipulating science goals, a cap of $500 million, and a flyby before 2020.

The turnaround followed outcry by the public and the science community, with the NASA Solar System Exploration Subcommittee’s rating a trip to Pluto as its highest priority. Not going now, proponents argued, would mean having to wait a quarter of a millennium until Pluto again comes close enough to the Sun for the planet’s atmosphere to thaw.

The winning Pluto mission is New Horizons, NASA announced on 29 November. Led by Alan Stern of the Southwest Research Institute in Boulder, Colorado, the spacecraft will be built by the Applied Physics Laboratory at Johns Hopkins University, and involves several other partner institutions.

“It’s a mini grand tour,” says Stern. “We’ll be exploring the frontier worlds near the edge of the planetary system.” Among New Horizons’ aims are characterizing Pluto’s atmosphere and mapping the surface compositions of Pluto, its moon Charon, and other Kuiper Belt objects. The mission is scheduled for launch in January 2006, with a Jupiter flyby and gravity boost in the summer of 2007.

Congress has approved $30 million for fiscal year 2002 toward a Pluto–Kuiper Belt mission. The White House, however, does not favor flying to Pluto, so finding funding for the outyears could still be iffy.