Lost in Space: Comet mission appears to have broken apart

August 21, 2002 at 10:14 am

Just 2 weeks ago, the CONTOUR probe, launched July 3, was beginning its journey to two comets, one of which had broken into pieces. It now appears that the $159 million spacecraft has itself broken apart.

FANTASY VERSUS REALITY. How the CONTOUR spacecraft might have appeared visiting a comet in 2006. Inset: Motion of what appear to be two pieces of the CONTOUR spacecraft on Aug. 15. Yellow circles containing black lines indicate positions of pieces 20 minutes later than positions shown as white lines. APL; Inset: J.V. Scotti, J.A. Larsen/ Spacewatch Project, U. of Ariz.

“I feel like I lost a relative,” says planetary scientist Lucy-Ann A. McFadden of the University of Maryland in College Park.

Engineers haven’t heard from CONTOUR, or Comet Nucleus Tour, since Aug. 15, when they commanded the craft to fire its solid-propellant rocket. The maneuver was intended to place CONTOUR on a path toward its first target, Comet Encke (SN: 8/3/02, p. 77: An assault on comets).

The most compelling evidence that something terrible happened came from a set of grainy images. Hours after CONTOUR fell silent, the Spacewatch Telescope near Tucson found two objects at CONTOUR’s predicted position and moving at its predicted speed, strongly suggesting the craft had broken up.

Although mission director Robert Farquhar of Johns Hopkins University Applied Physics Laboratory in Laurel, Md., is hoping that CONTOUR remains mostly intact and capable of functioning, “it’s not very encouraging,” he told reporters last week. As of press time, Farquhar and his colleagues hadn’t heard from the craft. If no signal comes by Aug. 25, he says, the best bet is a final search in December, when the probe’s antennas would be more aligned with Earth.

Astronomers have studied the nuclei of only two comets close up, Halley and Borrelly (SN: 9/29/01, p. 196: Probe’s comet encounter yields close-ups). If CONTOUR has indeed stopped functioning, researchers will have lost the opportunity for close-up studies of two additional comets, Encke and Schwassmann-Wachmann 3.

McFadden and her colleagues have another reason to lament the loss of CONTOUR. Data on Encke would have served as a guide for their own comet mission, Deep Impact. That probe, set for launch in 2004, will fire a projectile into Comet Tempel 1 and analyze the resulting debris.