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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Nov 29 2005, 10:31 AM
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Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
I'd have to dig in my "stacks" to find the review article that tried to evaluate a good number of candidates for Venus' Clouds against the observational data and failed. Hydrochloric was one of them, and flunked on a number of grounds, I think the main one being the observed abundance above the clouds was far to low for the clouds observed temperature. They'd have to have been much colder to have the observed HCL vapor levels.
Sulfuric Acid just didn't seem to be on anybody's list so the multiple choice answere was: D.) None of the above. It might have emerged as a leading candidate if it had been included in the list. Based on Venera and Vega descent composition data, and argued-about Pioneer Venus cloud particle spectrometer results, there are other composition particles in the clouds, but we know almost nothing about them, and the information is distinctly contradictory. Venera 13/14 and/or Vega 1/2 collected aerosol on a filter and then x-ray fluorescence'd them for element abundances, and got (besides sulfur), I think, Iron and Phosphourus. Iron Chloride was a proposed cloud component in the early 70's, I think. Sulfur crystals are one candidate for larger particles, but I don't know the current status on that as a candidate. Polarimetry has almost always been a technique in search of problems to solve in Planetary Science. Unfortunately, it's far less revealing of particle properties when measuring scattered light from solid, non-spherical particles, whether they're martian dust and ice hazes, Jovian etc ammonia and other hazes, or Titanian tholin smog. It does help study atmosphere structure, the size/abundance of aerosols with altitude, and the crude physical properties of the aerosol particles, but it's only had the one "mega-success" of nailing the main Venus cloud composition. |
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