OUR most recent odyssey to Mars began in July 1988, with the launch of two spacecraft called Phobos (1 and 2), and ended in March 1989, when ground controllers lost touch with the second craft. The international project involved 14 countries and the European Space Agency. It was the first flight designed especially to study one of the rocky minor bodies of the Solar System. Most of these orbit the Sun as ‘asteroids’, between the orbits of Mars and Jupiter. But Mars has two small moons that are probably asteroids captured by the planet. The space mission was intended to investigate the larger of the two, Phobos – hence its name.
The results from the Phobos mission came in three stages. The first were observations made as the spacecraft travelled between Earth and Mars; the second comprised observations and measurements of Mars; and the third, the observations of the moon Phobos itself.
Unfortunately, the Phobos mission did not carry out its programme in full. Early in September 1988, ground controllers lost contact with Phobos-1 after sending it an incorrect command. This switched off the orientation system of Phobos-1, and its solar panels stopped facing the Sun. With the onboard systems starved of power, the probe could not respond to any commands sent from the Earth.
After the loss of the first probe, the controllers took additional measures to make Phobos-2 more foolproof. They decided to correct its trajectory on the way to Mars only once, instead of twice as originally planned, even though this would increase the height of its orbit over the planet’s surface and produce fewer scientific results.
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