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> * (or "we can put a couple humans on Mars for 3 days for $100 billion")* Is there actually a NASA proposal like that? As far as I know, orbital dynamics don'
by wcoenen 6y ago
> * (or "we can put a couple humans on Mars for 3 days for $100 billion")*
Is there actually a NASA proposal like that? As far as I know, orbital dynamics don't allow for this. One has to wait for a Hohmann transfer orbit window to return home.
- garmaine 6y agoThere are faster transfer opportunities, but not 3 days. But I think he way saying 3 days of surface ops. Which is still an exaggeration. I think the NASA reference mission is 30 days?
- wcoenen 6y agoI had a peek at the Mars Design Reference Architecture 5.0 [1], and under "trajectory options" they talk about two classes of missions. "Opposition class missions" stay on the surface for 30 to 90 days. "Conjunction class missions" stay for 500 days or more. That confirms the 30 days that you mentioned as a reasonable minimum. [1] https://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf https://www.nasa.gov/pdf/373665main_NASA-SP-2009-566.pdf
- jccooper 6y agoThere is a "short stay" option, where you return on the same synod. This requires a higher-energy transfer, involving Venus on at least one leg, to get there early enough to hit the return window and also have enough time to actually do something on the surface. Apparently you can get up to 90 days in some situations, but 30 is more likely, out of a total elapsed mission time of 400-650 days. https://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html https://nssdc.gsfc.nasa.gov/planetary/mars/marsprof.html Of course, this in in the "resource-constrained" mode of thinking. If you allow for giant vehicles with on-orbit refilling, SpaceX-style, you just spend a bunch of energy to get there fast instead of monkeying around with Venus.