Future Venus Missions |
Future Venus Missions |
Jul 1 2005, 01:30 AM
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Solar System Cartographer Group: Members Posts: 10256 Joined: 5-April 05 From: Canada Member No.: 227 |
Oh well, might as well start that new topic since it's already well advanced in the Juno area...
My perspective on landers is as follows. All the landers we've had so far were dropped blind onto an essentially unknown surface. Any future landers can be targeted for specific terrains. It really is not true that we have had representative landings. Even a descent image or two, a panoramic photo plus a bit of surface composition, from a simple Venera-class lander just updated a bit, would be useful if we could put several down at well chosen targets. My choices would be: Examples of the main plains units (smooth, fractured, ridged) tesserae high elevation radar-bright tesserae large fresh lava flow unit ('fluctus') crater dark parabola crater ejecta outflow unit dunes area. And I have always assumed, rightly or wrongly, that it would be relatively easy to put these down, so they ought to be fairly inexpensive as planetary landers go. 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 28 2005, 03:34 AM
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Solar System Cartographer Group: Members Posts: 10256 Joined: 5-April 05 From: Canada Member No.: 227 |
Bruce, yes, lots of tesserae have small ponds of lava in low spots, and fingers of it extending from the plains, a common embayment relationship. They show up clearly in Magellan images, but please don't ask me to unearth one right now! There must be patches of aeolian sediment, dark parabola material or ejecta in low spots, or other complicating factors as well.
The trouble with the high res radar is that, yes, you get better images, but no, you still don't know exactly which spot the lander came down on. Only descent imaging can do that for you, or the very difficult task, likely to be almost impossible on Venus, of matching features in surface panoramas with orbital images. There is no other way to locate a landing site exactly at the scale needed for knowing its geological context. Of course this does not apply in the case of homogeneous plains. In tesserae or any other complex landscape you are still better to go with descent imaging if at all possible, using heavy compression if bandwidth is the issue. I just ran a test, and I can easily reduce a 1 MB TIFF to 25K without compromising its usefulness for site location, probably smaller. 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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