Following the launch failure of Saturday November 16, the Mars '96 probe has finally returned to Earth. Pieces of the probe crashed at 01:34 UT into the Pacific Ocean, 900 miles southeast of Easter Island at 31 degrees south and 96.3 degrees west.

Igor Lissov of Novosti Kosmonavtiki reports:

There're some details on Mars 96 mission events based on Monday news conference in the Russian Space Agency. The mission was more difficult (and interesting) than we could think.

Short info:

Proton-K launch vehicle with Block D-2 upper stage and Mars 96 spacecraft (a.k.a. Mars 8) was launched from Baykonur on Nov.16 at 20:48:53 UTC.

Mars 96 with its small stations, penetrators and radioisotopic generators reentered early on November 17 on orbit 3 near perigee, presumably in the Soutern Pacific.

Block D-2 reentered on November 18 at approx. 01:13 UTC and parts of it fell into the Southern Pacific at 01:20 UTC at 50.9S, 168.1W.

More details:

Proton-K (8K82K) worked perfectly and Block D-2 (11S824F) first burn was made successfully. Initial circular 160 km orbit was deduced from measurements from ground stations during LEO insertion and part of orbit 1.

The planned second burn of 3150 m/sec by Block D-2 engine was not achieved. Instead, some 20 m/sec in wrong direction was given by Block D-2 resulting in Block D-2 orbit of 145.7x171.1 km. This was object 1996-064A and it lasted for 28.5 hours. On orbits 2 through 5, telemetery from Block D-2 was recieved. Then the upper stage was not in sight from Russian ground stations and by evening of November 17, chemical batteries were depleted and communications from Block D-2 was not restored. It barely missed Australia and ended in the Pacific.

Mars 96 separated from Block D-2 after unsuccessfull second burn in the beginning of orbit 2. Solar battaries and external elements were deployed and the spacecraft tried to catch the required velocity by its own engine, the ADU. This was impossible because the spacecraft had not enough fuel to make a 3700 m/sec delta-V. So, this burn was not successful either. Moreover, it effectively killed Mars 96.

On orbit 2, telemetery from Mars 96 was recieved at Yevpatoriya ground station in Crimea from 22:19:14 till 22:26:55. Ussuriysk station also recieved signal from Mars 96 from 22:55-22:57. (Different transmitters were used on Mars 96 and Block D-2 so the controllers can say for sure which object they tracked) The spacecraft was found in a kind of orbit of 87x1500+some km. It survived the first perigee and was tracked by the Russian Center for Space Surveillance on orbit 3, some 100 minutes after orbit 2. By this time, flight controllers were ready to command Mars 96 to maneuver to some stable LEO orbit for possible future use in Earth research. Unfortunately, flying at 87 kilometers proved to be too bad. On orbit 3, Mars 96 wasn't transmitting already and cannot be commanded.

Mars 96 was not tracked on orbit 4 and the conclusion was that it reentered in orbit 3 perigee somewhere in Southern Pacific.

Igor Lissov
Novosti Kosmonavtiki
VideoCosmos Co.
Moscow, Russia

More news on Mars '96:

IKI's Mars '96 Homepage
Latest news on CNN
Florida Today Space Online

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