Phobos 1: trouble on the way to Mars.

Phobos 1: Trouble on the way to Mars

The first spacecraft sent toward Mars since the two U.S. Viking craft took off in 1975 is in trouble. The Soviet Union's Phobos 1 vehicle, launched on July 7 and due to reach the little Martian moon Phobos in January, went out of control on Sept. 2 after a ground controller sent it an incorrect command.

The craft is one of two in the elaborate mission, designed to photograph, probe and sample its target (SN: 6/18/88, p.392). But Phobos 1's problems affect more than just the Mars mission. Scientists have hoped Phobos 1 would work jointly this month with the Earth-orbiting U.S. Solar Maximum Mission satellite, making stereo images of the sun by looking at it simultaneously from different angles. The U.S.-Soviet collaboration has been anticipated as a major activity in a 13-country effort called the International Solar Month (SN: 8/27/88, p.134).

Phobos 1 and Phobos 2, launched July 12, are similar but not identical. Phobos 1, for example, is the only one equipped with the white-light coronagraph and X-ray telescope envisioned for the solar observations. It is also the only one carrying an extreme ultraviolet solar emissions detector, as well as a neutron spectrometer whose measurements could help researchers judge the water content of Martian rocks. Phobos 2, on the other hand, has the mission's only "hopper," designed to be deposited on the moonlet's surface, where it will jump from place to place on spring-loaded legs, making measurements at the different sites.

Phobos 1's problem appeared when the craft apparently lost its proper orientation and began following a conical wobble, so that its solar panels failed to pick up enough energy to sustain even its transmitter. Nothing had been heard from the craft as recently as Sept. 14, but officials were hoping the solar panels might get properly aligned with the sun later this month to restore power.