Sending Men To Venus |
Sending Men To Venus |
Jul 20 2005, 04:40 PM
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Member Group: Members Posts: 212 Joined: 19-July 05 Member No.: 442 |
While it is likely that future Venus missions will be robotic craft, at one point someone in NASA carried out an interesting contingency study on sending a manned craft to orbit Venus.
The file (Click here:Manned Venus Mission 1967) works on the assumption that either the NERVA project had been carried through to completion or that NASA had retained the capacity it was developing for Apollo. While the author does not rule out the possibility of a landing on Venus, he notes that owing to the unknown surface conditions they would be highly unlikely. Launch times are given as being between 1975-1986 and are designed to allow 40 days in orbit at Venus. As someone who was growing up during the period mentioned I would like to say that such missions would have been far more interesting than what actually occurred. |
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Jan 10 2008, 07:54 AM
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Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
It still occurs to me that surface sample return is beyond our capabilities at the moment. Venus has a gravity field very similar to that of Earth -- you would need something more powerful than a Delta II to get a sample off the surface and into an escape trajectory, I would think (especially when you consider how much more atmospheric drag it would encounter on the way up).
That's an awfully big rocket to land on Venus and to engineer such that it will survive any sort of surface stay long enough for teleoperations. Here's a question, though: just how valuable would a sample of Venusian air, collected at, say, 50km altitude, be? We're still above a lot of the atmosphere at 50km, right? You could design an entry probe to pump a chamber full of Venusian air (complete with dust particles, etc.), or perhaps several chambers at different altitudes. Then, when the vehicle is still moving relatively fast (we're talking Mach 6 to Mach 10 operations, here) all you would really need to boost the sample chamber(s) back to an escape trajectory would be something like one of those air-to-orbit rockets. I'd think the data on isotope abundances and elemental compositions of dust particles would make the samples worthwhile, and you could collect such samples and then rendezvous the collection chamber(s) with a manned flyby, just as John described. What do y'all think? -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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Jan 10 2008, 08:21 AM
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
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Jan 10 2008, 08:43 AM
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Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
Launch from the surface of Venus is definitely a dicey proposition (imagine a Delta rocket descending by parachute into a 900F hell and the liquid propellant not exploding). With the density of Venus' atmosphere, I think any rocket would have severe gravity loss penalties. You would need to avoid any significant dynamic pressure (easily builds up in Venus atmospheric density) and I think that'd actually imply subsonic velocities (and you still might have high losses due to air drag) for much of the atmospheric ride up. How does this translate to gravity losses? If you're constrained to a velocity, your acceleration is even more constrained. The best (cheapest in terms of delta-V) way to get something into orbit is to send it up as fast as possible to minimize the time gravity decelerates you before you go on a ballistic trajectory with negligible further gravity losses. Fast accelerating rockets in other words. On Venus, your inertial acceleration would be limited to about 1 G (giving a total of about zero for early phases of flight) for a long time so the gravity losses would skyrocket. You'd need much more total delta-V imparted by the rocket than on Earth precisely because you're not allowed to accelerate fast enough in the lower atmosphere. It begs the question if rockets can be even remotely feasible on Venus and that's even neglecting high surface temperatures and pressures and issues they cause with propellants. -------------------- |
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