Quote:
Originally posted by damienpaul@Jan 12 2004, 04:04 AM
thats actually an interesting point, it just occurred to me that maybe we have several orbits and orbital fluctuations actually not accurate enough. Is this at all possible as a scenario and explanation?
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It seems unlikely, most of the Russian Mars probes seemed to have failed either near to Earth (usually booster failures of some sort) or enroute to Mars (usually some sort of electronics failure causing loss of radio communication). Some exceptions were Mars 5 (failed after a few days in orbit) & 6 ("lander failed on impact") as well as Mars 7 which is described as "Lander missed the planet"! Mars 2 burned up entering the Martian atmosphere and Mars 3 failed 20 secs after landing on Mars.
The American failures are pretty similar but less frequent--Mariner 3 failed during boost phase when the shround failed to separate from the upper stage, Mariner 8 "failed during launch", Mars Observer launched in 1992 apparently failed as it tried to fire it's main engine to enter orbit around Mars (as I recall they think the engine exploded) and of course the Mars Climate Orbiter failed in '98 due to the infamous metric/imperial units snafu and burned up in the martian atmosphere having stepped on the brakes too hard. Mars Polar Lander is believed to have crashed due to a software fault causing premature shutdown of the retro rockets during final descent phase.
So maybe Mars 7 could be blamed on orbital navigation issues, but apparently none of the others.