Monday, August 20, 2007

Phobos 1 & 2

Credit: Russian Academy of Sciences/Don P. Mitchell

And then began the long wait...

As Oliver Morton wrote in his book, Mapping Mars, "The failure to find any trace of life on Mars in the 1970s was as harsh a blow to science fiction as it was to science. It had almost always been the Martians, rather than their planet, on which the fiction had focused. From the mid-1970s to the mid-1980s there was remarkably little new science fiction about Mars." (p. 136)

The dearth in Mars-oriented science fiction went hand in hand with the dearth in missions to Mars. From 1975 through 1988, no new missions were launched by any country. Granted, the various Viking Orbiters and Landers remained operational from 1976 through 1982, providing a diminishing flow of new data as the Landers and Orbiters eventually went silent. However, from November 1982, when the Viking 1 Lander died, through January 1989, there were no working spacecraft on or orbiting Mars. Moreover, there were no attempts in the various launch windows in all those years, in contrast to the eleven missions launched in the past six launch windows, since 1996 (with seven missions successful, five missions still operational, and one, the Phoenix Mars spacecraft just launched).

In July 1988, the Soviet Union sent their first mission to Mars since 1973, when they had launched the four spacecraft, Mars 4 through 7. These two spacecraft, Phobos 1 and Phobos 2, were the first to focus primarily on the Martian moon, Phobos, in addition to Mars. Each spacecraft was a combination orbiter-lander (although, in the case of Phobos 2, there were two landers). The objectives of the Phobos Program were to: conduct studies of the interplanetary environment, perform observations of the Sun, characterize the plasma environment in the Martian vicinity, conduct surface and atmospheric studies of Mars, and study the surface composition of the Martian satellite Phobos.

Phobos 1 was launched on July 7, 1988 and was operating normally through September 2nd, when mission controllers were unable to contact the spacecraft. A few days earlier, on August 29th and 30th, some software had been uploaded that accidentally deactivated the attitude thrusters. Phobos 1 lost its lock on the Sun and could no longer orient its solar arrays properly, depleting its batteries.

Phobos 2 was launched five days later, on July 12th, and entered Mars orbit on January 29, 1989. The spacecraft was able to take a total of 38 different pictures using a number of different cameras, including a video-spectrometric complex (VSK), three CCD cameras and a optical-mechanical linear camera that operated simultaneously in red/near-infrared light (600 - 950 nm) and far thermal infrared (8.5 - 12 μ), using a cryogenically cooled detector. As mentioned above, Phobos 2 also carried two landers. Both were to land on Phobos, one being a stationery platform and the other a mobile "hopper." However, on March 29th, as Phobos 2 neared its namesake satellite, communications was lost. The cause of the failure was determined to be a malfunction of the on-board computer.

The above picture is a near infrared scan of Mars, taken during the daytime on March 26, 1989. Starting on the left, the large circular feature is the southern-most of the three prince volcanoes, Arsia Mons. Moving to the right, the large triangular region made up of a maze of deep, steep-walled valleys is Noctis Labyrinthus ("The Labyrinth of the Night"). Across the center of the image is the vast Valles Marineris, ending in the Eos Chasma to the right. In the darkness at the far right is Margaritifer Terra. The area directly south of Valles Marineris is Sinai Planum, and the area to the northeast of Valles Marineris (and northwest of Margaritifer Terra) is Xanthe Terra.

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