Mariner Mars 1964, Mariners 3 and 4 to Mars: imaging plans? |
Mariner Mars 1964, Mariners 3 and 4 to Mars: imaging plans? |
Apr 28 2005, 05:05 PM
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Solar System Cartographer Group: Members Posts: 10226 Joined: 5-April 05 From: Canada Member No.: 227 |
I am currently working on a book about lunar exploration, but looking ahead to the next one, which will cover Mars. One question to which I think I have an answer - but I'd like to see what my fellow Mars enthusiasts think - is this:
Mariner 3 failed to leave Earth. But if it had flown successfully, what area on Mars would it have photographed? My understanding is that there was no specific plan. The MM64 press kit, for instance, says nothing about image coverage for either Mariner 3 or Mariner 4. I believe that navigation to planetary distances was still so uncertain that the flight team could not predict at launch the sub-spacecraft point at closest approach - uncertainties included the exact time of the flyby, the distance and the point at which the spacecraft would pass through the target plane. These things would be known closer to the flyby but they weren't precisely predictable at launch, so Mariner 3 never got to the stage of having an imaging plan. Am I right? Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PDF: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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May 1 2005, 07:59 AM
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
Mariner 69 and it's mission was designed around a much slower communications link than they ended up using. ... some 512 bits/sec compared with 8 <at mars> for Mariner 4. The 16,200 bps data rate was an "engineering test" included on teh spacecraft. The original goal was to tape some 8 late far encounter full disk images and fill the rest of the tape with near encounter images.
Since the high-data-rate link worked flawlessly and clearly had plenty of margin at Mars, the mission ended up using it for all it was worth. Similarly, Mariner Venus/Mercury 1973 <Mariner 10> was designed around a 16,200 or whatever datarate, and included an engineering-test data rate of 144,000 or some such data rate with the intent of using it for real time transmission of all data if it worked and taping the closest encounter frames on a Mariner 9 vintage tape for backup and multiple replay to get best quality data. |
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