Phobos 1
Illustration of the Phobos 1 spacecraft
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| Operator | IKI |
|---|---|
| COSPAR ID | 1988-058A |
| SATCAT no. | 19281 |
| Website | Phobos Mission |
| Spacecraft properties | |
| Launch mass | 6,220 kg (13,710 lb) |
| Start of mission | |
| Launch date | 17:38:04, July 7, 1988 |
| Rocket | Proton-K 8K82K/D-1 |
| Orbital parameters | |
| Reference system | Areocentric |
| Epoch | planned |
Phobos 1 was an unmanned Russian space probe of the Phobos Program launched from the Baikonour launch facility on 7 July 1988. Its intended mission was to explore Mars and its moons Phobos and Deimos. The mission failed on 2 September 1988 when a computer malfunction caused the end-of-mission order to be transmitted to the spacecraft. At the time of launch it was the heaviest interplanetary spacecraft ever launched, weighing in at 6,200 kg.
It was to take an estimated 200 days for the Phobos 1 space probe to travel from the Earth to Mars. Two mid-course corrections were planned. The first between days 7 and 20, and the second between day 185 and 193. These corrections would place the probe in a highly elliptical orbit around Mars. Next, it was to move into an almost circular observation orbit at 350 km. After achieving observation orbit the lower stage of the propulsion system would be dropped. The probe would then rendezvous with Phobos; drop a lander containing scientific equipment from an altitude of 50 meters, and move into a final equatorial orbit above Mars where it would study the martian surface and atmosphere.
The Phobos 1 probe's scientific study was separated into three phases. In stage one the probe would investigate the Sun and interplanetary space while traveling from the Earth to Mars. In stage two the probe would study Mars and Phobos while in orbit around Mars. During the final stage it would approach to within 50 meters of the Phobos surface while conducting several experiments.
The Phobos probe carried several scientific experiments. It carried a radar transmitter, X-ray and alpha-backscatter spectrometers, camera, and a laser that could vaporize tiny spots so a reflector could analyze the vapor for atomic masses.
The probe also carried a "hopper". The hopper would be dropped onto Phobos to drill and analyze the soil. It would be able to bounce across the terrain by using spring loaded legs.
On September 2, a faulty key-command was sent up to Phobos 1 from ground control in Yevapatoria. A technician unintentionally left out a single hyphen in one of the keyed commands. All commands were supposed to be proofread by a computer before being transmitted, but the computer that checked code was malfunctioning. The technician violated procedure and transmitted the command before the computer could be fixed to proofread it. This minor alteration in code caused the end-of-mission command to reach the spacecraft; shutting down all of the systems aboard Phobos 1.
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