In regards to [a] request for information on the Soviet PHOBOS 1-2 missions to Mars, the following is revised from an article I wrote on the history of Soviet Mars exploration in the October 1989 issue of the Electronic Journal of the Astronomical Society of the Atlantic (EJASA). I hope it will be found useful. THE ROCKY SOVIET ROAD TO MARS Copyright (c) 1990 by Larry Klaes [...] Revived Ambitions for the Red Planet The Soviets were not completely idle with their Mars program. By the early 1980s, the Space Research Institute of the Soviet Academy of Sciences, lead by its director, Roald Z. Sagdeyev, were developing plans for a whole new series of robot Mars explorers. The ultimate goal of these efforts were to lead to manned expeditions. As the decade progressed, new spacecraft designs were emerging from the Soviet Union, sometimes being revealed to the rest of the world far in advance of their launchings. This was something almost unthink- able only a few years earlier. Much of this behavior came about from the changes in the Soviet political climate, brought on by Soviet President Mikhail Gorbachev. Like Krushchev, Gorbachev wanted to bring the Soviet Union up to the standards of the modern world. Unlike his predecessor two decades earlier, Gorbachev decided to follow this path by frequently working with other nations, rather than treating them as adversaries. One of the results of this new political climate was the PHOBOS program, whose existence was announced in 1983, five years before its scheduled launch. PHOBOS was ambitious in many new areas. Two 6,220-kilogram (13,684-pound) probes were to be sent to study the Martian moon Phobos, as well as Mars itself and possibly its smaller moon, Deimos. The craft would drop several small landers on the dark, cratered face of Phobos, a first in the history of space exploration. Studying the Martian moons made a great deal of sense from the point of view for human exploration. The satellites' close proximities to Mars and low masses could serve as excellent "space stations" for crews preparing to land on the Red Planet. The two PHOBOS spacecraft were to be launched from the Soviet Union in the summer of 1988 and go into orbit around Mars early the following year. The orbiters would wait several months, studying Mars and its moons, while they achieved the proper trajectory to flyby Phobos at the incredibly low altitude of fifty meters (165 feet). At this point that the orbiters would drop off three landers (one from PHOBOS 1 and two from its sister craft), two of which would anchor themselves with a harpoon into the dusty soil of the small moon. The other lander would use metal bars to move across Phobos' surface by "hopping" until its batteries ran out of power. The landers would send images and information about the moon to their orbiters, which would relay the data back to Earth. The United States would play a vital role in the communications aspect of the mission by using NASA's Deep Space Network (DSN) of radio telescopes to pick up PHOBOS' weak signals during their missions, just as the Jodrell Bank radio telescope in Great Britain had done for the Soviets in their Mars missions two decades before. There was also a variety of scientific equipment from over a dozen other nations onboard the probes. The complexities and international cooperation of the mission were meant to be a sign of the great things to come in the Soviets' renewed ambitions towards the Red Planet. PHOBOS Heads to Mars PHOBOS 1 left the launch pad at Tyuratam on July 7, 1988, atop a PROTON rocket, followed by PHOBOS 2 on July 12. Like the Mars probes sent before them, the PHOBOS craft conducted studies of the Sun and interplanetary environment while in transit towards the Red Planet. On August 31, PHOBOS 1 was being prepared for an important international solar experiment. During one of the regular communication sessions with the probe, a command message with one character accidentally omitted was sent to the craft. This seemingly minor incident quickly snowballed as PHOBOS 1 was subsequently given a computer command to shut off its attitude control system. The resulting error caused the probe to begin tumbling, aiming its solar panels away from the Sun. Power in the spacecraft dropped dramatically until it could no longer function, and communications ceased. Despite several days of intense efforts by the Soviets to re-establish contact, PHOBOS 1 was permanently silent. Mission officials became extremely cautious about ensuring the continued functioning of PHOBOS 2, as it was now the only PHOBOS spacecraft left to carry out the mission objectives; however, even their pampering was not enough to keep PHOBOS 2 from developing troubles of its own. As the probe neared Mars, the main fifty watt transmitter aboard the craft malfunctioned, leaving only the five watt backup to keep PHOBOS 2 in touch with Earth. The main bus cameras and several scientific instruments also malfunctioned along the way, though they were later corrected by the time PHOBOS 2 went into Mars orbit on January 29, 1989. For the next two months, the craft spent its time examining Mars and Phobos, while adjusting its altitude above the planet to match that of its target moon. Placement of the two landers on the surface of Phobos was scheduled to occur around April 7. On March 27, almost two months after PHOBOS 2 was placed in orbit around the Red Planet, controllers ordered the craft to orient itself to take photographs of Phobos. Since the probe's main antenna was not on a separate swivel platform from the orbiter, the entire craft had to be turned away from Earth while the picture set was being taken. It would then reorient itself to transmit the images to Earth. Instead, the technical problems which have haunted the Soviet Mars missions since their beginning caught up with PHOBOS 2. The orbiter turned away for the imaging, but did not turn back as planned. For two hours after the mishap, Soviet controllers tried to raise the craft. They were rewarded for thirteen minutes when faint signals were received from the probe, but soon after the signals disappeared, PHOBOS 2 was not heard from again. It was surmised that, like its sister probe, PHOBOS 2 began to tumble when contact with Earth was lost, and the craft eventually shut down when its solar panels moved away from direct sunlight. Ironically, the orbit of PHOBOS 2 might inadvertently cause the probe to someday become the first human-made vehicle to land on the surface of the Martian moon, though certainly not in the manner it was intended. Two main theories quickly arose as to the cause of PHOBOS 2's permanent silence. Perhaps some debris, a meteor or even the probe's jettisoned propulsion module, had struck the spacecraft, disorienting it and pointing the antenna away from Earth. The attitude control system (possibly a faulty gyroscope) might also have malfunctioned when the craft turned away from Earth to photograph its target moon, and then could not aim the spacecraft back at its planet of origin. Project officials have since come to believe that an onboard computer may have had either an internal malfunction or been affected by a power supply problem. Another contribution to the ultimate failure of PHOBOS 2 may have come from the revelation of a lack of overall cooperation between the spacecraft's builders and the mission scientists. Such divisions will need to be removed if future Mars projects are to be successful, particularly when other nations and human life are involved. Though the Soviets officially wrote off PHOBOS 2 on April 18, 1989, the mission was not without its successes. The first spacecraft to explore the Red Planet since the accidental shutdown of the VIKING 1 lander in November of 1982, PHOBOS 2 made a number of important studies with a variety of instruments at its disposal in the two months it functioned high above Mars. One experiment named FREGAT used Charged Coupled Device (CCD) images of Phobos to reveal that the moon is uniformly gray in color and recorded areas missed by the VIKING orbiters ten years earlier. A scanning radiometer designated TERMOSKAN made infrared images of the surface of Mars, indicating previously unknown warm and cool regions of the planet. [...] Should MARS 1994 succeed, the Soviets may head back for the moon Phobos again several years later, this time going several steps further with the mission goals set for PHOBOS 1 and 2. Two PHOBOS- type craft would be sent off into space in 1996-1997, one to the small Martian moon, the other to investigate a number of planetoids beyond the orbit of Mars, including Vesta. The Phobos probe would drop a lander on Phobos to analyze the moon, and perhaps even return soil samples of the tiny world to Earth - the first acquisition of material from another planet's moon. [...] Bibliography: Johnson, Nicholas L., THE SOVIET YEAR IN SPACE (1988 and 1989), Teledyne Brown Engineering, Colorado Springs, Colorado. Miles, Frank, and Nicholas Booth, RACE TO MARS: THE MARS FLIGHT ATLAS, Harper and Row, Publishers, New York, 1988. ISBN 0-06-016005-5 Smith, Arthur, PLANETARY EXPLORATION: THIRTY YEARS OF UNMANNED SPACE PROBES, Patrick Stephens Limited, Wellingborough, Northamptonshire, England, 1988. ISBN 0-85059-915-6 Wilson, Andrew (Editor), INTERAVIA SPACE DIRECTORY 1989-90, Jane's Publishing, Inc., New York, 1989. Wilson, Andrew, SOLAR SYSTEM LOG, Jane's Publishing, Inc., New York, 1987. ISBN 0-7106-0444-0