Soviets’ Martian Moon Probe in Trouble : No ‘Stable Radio Contact’ With Phobos 2; Sister Ship Lost Earlier

Times Science Writer

Soviet scientists have lost “stable radio contact” with a spacecraft scheduled to rendezvous with the Martian moon of Phobos late next week, an ominous development that could mean the most ambitious planetary program that the Soviets have attempted in the past decade may be in serious jeopardy.

The spacecraft, called Phobos 2, is the survivor of two unmanned craft launched toward Mars last July.

According to a report by the official news agency Tass, the spacecraft’s “on-board control system” ordered the craft to turn Monday so that its camera could take pictures of the moon Phobos.

“After these operations were completed, the information was to be sent back to Earth, but mission control was unable to establish stable radio contact with the probe as scheduled,” the report said. “The possible causes of the loss of contact are being analyzed, and efforts are continuing to regain it.”


The first craft, Phobos 1, was lost last October when a ground controller sent it an erroneous computer message, disorienting it so that its antenna was no longer pointed toward Earth and thus could not receive commands. After trying unsuccessfully to re-establish contact, Soviet officials finally abandoned the effort.

The loss of the first craft was considered a major setback, because it had special instruments to study the sun that were not duplicated aboard its sister ship. But at the time, Soviet scientists could take heart in the fact that they had a second craft, launched just five days after the first, that could carry on the mission. Redundancy has been the hallmark of the Soviet space program.

But it is the second craft that is now in jeopardy.

The extent of the problem was not clear in the United States on Tuesday, largely because the Tass report included few details. The National Aeronautics and Space Administration, which has assisted the Soviets in the Mars mission through its deep space network of antennas, was scheduled to hold a teleconference with Soviet officials this morning to see if any further assistance is needed.


NASA would not speculate on the nature on the problem, and the space agency’s scientists have been specifically prohibited by NASA from commenting on problems with Soviet spacecraft. The attitude in NASA is that bad news ought to be announced by the Soviets, not by NASA officials.

If the second craft is lost, the Phobos mission will be a total failure except for some data that was radioed back to Earth as the craft orbited Mars over the past few weeks.

13 Nations Participate

The Phobos mission is an international effort involving scientists from 13 nations, including the United States. Most of the scientific instruments aboard the craft have been provided by European countries.

The loss of “stable radio contact,” coupled with a change in the orientation of the spacecraft, could mean that the craft failed to return fully to the correct position, with its antenna pointing directly to Earth. All may not be not lost, however, if it is possible to communicate at all with the craft.

On April 7, the spacecraft is scheduled to go through a very exacting maneuver. It is to skim over Phobos--just 150 feet above its icy, rocky surface--and deploy two landers. One of the landers is supposed to hop around Phobos, which is only about a dozen miles in diameter, studying the soil. The second is to attach itself permanently to the surface and carry out a wide range of experiments.

The spacecraft must operate in an automated mode for those goals to be carried out because it takes too long for commands to be transmitted back and forth between Earth and Mars for ground controllers to guide it through the precise maneuvers. Thus, any problem with the craft’s on-board control system is considered extremely serious.

The Phobos mission has been a high profile project for the Soviet space community. Western journalists were permitted to watch the launches last July and have been given extraordinary access to Soviet scientists involved in the mission, thus making it a showcase for the country’s new spirit of openness.


More than a decade ago, the Soviet Union attempted several planetary missions, all ending in failure. Meanwhile, the United States claimed almost exclusive domain over the planetary sciences with missions to various planets, including Mars. U.S. Viking spacecraft actually landed on the surface of Mars in 1976 and sent back photos. Even earlier, the Mariner 9 craft orbited the planet and sent back the first close-up photos ever of Phobos.

The two Phobos spacecraft represented the Soviet Union’s re-entry into the arena of planetary exploration. No Soviet spacecraft has ever landed on the moon of another planet.