LOSS of the spacecraft the Soviets sent to study the Martian moon Phobos is an international tragedy that focuses attention on NASA's 1992 Mars Observer launch. This now becomes the first opportunity for international cooperation in Martian exploration.
The two Phobos spacecraft launched last July had come to symbolize this cooperation. Scientists from many countries joined the Phobos team as the Soviets abandoned their former secrecy and opened their civil space program for wide foreign participation.
Then, last September, a technician's error disoriented Phobos 1 and the craft lost contact with Earth. Now, controllers have been unable to reestablish contact with Phobos 2, having lost it a week ago, apparently because of some spacecraft failure. There had been trouble with some Phobos 2 systems for several months.
Phobos 2 has returned some data, including pictures of Mars and Phobos. It has found evidence that Mars, like Earth, may have encircling ``radiation belts'' of electrically charged particles trapped in a magnetic field. But, essentially, the mission seems to be lost. MEANWHILE, American and Soviet scientists, working under agreements for cooperation in Mars exploration, have been studying how to coordinate their programs. Together with foreign partners, they want to extend the cooperation begun by the Phobos mission to make the 1990s a decade of international Mars study.
NASA's 1992 Mars Observer mission is to put a spacecraft into orbit around Mars to make detailed surveys of the planet's surface and atmosphere. Its mission now is to include cooperation with a Soviet mission, planned for 1994, that would drop balloons and even roving vehicles on the Martian surface.
Beyond this, NASA, the Soviets, the European Space Agency, and other national space agencies have begun study of a possible joint mission to return some Martian samples to Earth late in the next decade.
It is too soon to know how the Phobos failure will affect these plans. But the future of the Soviets' 1994 mission is now uncertain.
The failure will also reinforce the American position that US-USSR cooperation must be planned in such a way that the failure of one partner's equipment won't jeopardize the main mission of the other partner.
Mars has been a frustrating target for the Soviets. They have conducted 19 Mars missions over 28 years, 17 of which failed. The other two missions were flights to make engineering tests not scientific observations.
The missions failed for a variety of reasons including rocket explosions, failure to orbit, failure to leave Earth orbit and head for Mars, on-board equipment failure, and human error.
Soviet scientists continued to try for Mars until they lost four missions in 1974.
Although their Mars program did return some data and did succeed in landing instrument packages (that malfunctioned), it had generally been a failure. They then abandoned Mars for 14 years, finding more success in studying Venus and Halley's comet.
SEEN in this perspective, the loss of the two Phobos spacecraft is more disheartening for Soviet space scientists than just the failure of an important mission. It can seem like the renewal of a historical pattern of failure in trying to study the Red Planet. The Soviets, however, have been remarkably persistent in trying to rise above such failure.
Experts in other countries who have commented on the failure expect the Soviets to try again. And this time, they can look for international help and encouragement that was unavailable in 1974.