ExoMars - Schiaparelli landing |
ExoMars - Schiaparelli landing |
Aug 12 2016, 07:07 PM
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#101
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Solar System Cartographer Group: Members Posts: 10172 Joined: 5-April 05 From: Canada Member No.: 227 |
Starting a new topic here - hopefully that's OK! Clearly there will be a lot of action around this in the next weeks and months with descent images and HiRISE views of the hardware.
I thought I had posted this map earlier but apparently not. This shows the various landing ellipses in this area. The original plan was for an ellipse oriented NW-SE, but it changed with the different launch date and is now nearly E-W. Note that the ellipse shown in the recent ESA release is the envelope of all ellipses over a given launch period, but the actual landing ellipse for the given launch date is smaller. Opportunity's final landing ellipse is shown for comparison. http://exploration.esa.int/mars/57445-exom...6-landing-site/ http://exploration.esa.int/mars/57446-exom...6-landing-site/ 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 PD: 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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Oct 30 2016, 04:58 PM
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#102
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Senior Member Group: Members Posts: 2346 Joined: 7-December 12 Member No.: 6780 |
I should have remembered that from a few days before...
If it's really pure hydrazine with no water content, it freezes near 2 C. According to this article, the vapor pressure of solid hydrazine at 0 C is 2.60 mm Hg or 2.60 hPa x 1013.25 / 760 = 3.47 hPa. Therefore at estimated 6 hPa on Mars, there should be a narrow temperature range, where hydrazine would be an oily liquid. But due to the zero partial hydrazine pressure on Mars, it will boil, then evaporate until it freezes, then sublimate. But again, it is likely to decompose in an explosion on impact: QUOTE Hydrazine is listed among shock-sensitive chemicals, as a chemical prone to rapidly decompose or explode when struck, vibrated, or otherwise agitated. Or on contact with the surface material on Mars, especially with the iron oxides bearing dust: QUOTE Hydrazine spontaneously explodes upon contact with calcium oxide, barium oxide, iron oxides, copper oxide, chromate salts, and many others. This may be dependent of the temperature, but it's reasonable to assume, that the hydrazine in the tanks was warmed and liquid on impact. If the hydrazine contains some stabilizing additive, odds for staying stable on impact might be a little better. But it will nevertheless react or decompose in the Martian environment after days or weeks. |
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