NASA Scientists Mourn Cancellation of Asteroid Probe

Scientists on Friday lamented the cancellation of a NASA mission to orbit two asteroids, saying the project would have shed light on how the solar system formed.

NASA axed the Dawn mission on Thursday, five months after it was put on hold because of cost overruns and technical problems.

The Dawn spacecraft would have made a nine-year voyage to two of the solar system's largest asteroids, Ceres and Vesta, which reside in the main asteroid belt between Mars and Jupiter.

Project scientists and engineers exchanged a flurry of e-mails after news of Dawn's demise, expressing shock and disappointment, said Bruce Barraclough of Los Alamos National Laboratory, a Dawn science team member.

"After you've worked on something for so long and put your heart and soul into it, this is heartwrenching," Barraclough said.

The cancellation of Dawn comes as NASA is trying to fulfill President Bush's space exploration vision to retire the space shuttle fleet and develop a new manned spacecraft to return to the moon in the next decade.

NASA has been forced to delay several high-profile science projects including two telescope missions that would search for planets capable of supporting life.

Dawn is the latest mission managed by NASA's Jet Propulsion Laboratory in Pasadena to face the chopping block. Last year, two JPL-managed missions to explore Jupiter's icy moons and gather data about Mars' atmosphere were scrapped to free up money for human exploration.

Andrew Dantzler, director of NASA's solar system division, said Friday that cost and technical concerns eventually forced the space agency to cut Dawn. An independent team found 29 technical issues that needed to be resolved and would have delayed the mission another year, he said.

"The more we dug, the more we became concerned," Dantzler said.

Bill Feldman of the Los Alamos National Laboratory said he was stunned to learn about Dawn's cancellation. He added that scientific knowledge about how the sun and planets formed would be lost by not moving the project forward.

"We need to suck in our guts and rehabilitate this mission and fly it one way or another," Feldman said.

Dawn would have been the first spacecraft to circle Vesta and Ceres, which scientists believe formed in different parts of the solar system and had different evolutionary processes.