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NASA: Let's Explore Venus in Solar Zeppelins and Build a Cloud City

4 points by stevenjgarner 12y ago

stevenjgarner 12y ago
Could Venus be a more enticing option for an upcoming manned mission than Mars? Not having to perform descent and subsequent launch, such a mission presumably could be done for a fraction of the cost of a Mars mission.
- dalke 12y ago
  There are three possible mission plans I know of for Venus. 1) Venus flyby, like what was planned in the 1970s with Apollo hardware. 2) Orbit Venus, and 3) this one to descend into the atmosphere. For Mars there are four: 1) flyby, 2) orbit, 3) land on one of the Martian moons, 4) land on Mars. The latter has a variant: Zubrin proposed that we can make rocket fuel on Mars and use that for the ascent and/or return. Of these, I don't see why a flyby does anything other than say we did it. Our automated probes are now much more capable than we had in the 1960s/1970s. Though if a human were useful, the Venus is definitely quicker to get to than Mars. As far as I can tell, it's about the same amount of delta-v to get to Mars as Venus, so orbiting either is possible, except the longer flight time for Mars and back means a lot more extra supplies (something like 5kg/day * 14 months?) and more risk of something going wrong. Venus comes out ahead. But what does a human orbiting either planet add that a robotic probe does not? The most often given example is fast response time for a rover, since it's at least a 4 minute lag for Venus and 6 minutes for Mars. I would rather have a dozen slow rovers on the ground controlled from Earth, or a dozen long-term probes orbiting the gas giants than a single one by a human above Venus. In any case, we know we can put capable rovers on Mars. On Venus they tend to melt. This one to descend into the atmosphere of Venus means a return vehicle almost as powerful as what's needed to get someone off Earth. That's going to be tough to solve. Our biggest balloon launched rockets are, I believe, from amateur organizations. OTOH, robots don't need to come back to Earth. Landing on a moon of Mars would combine Mars observations and visual exploration of (what's believed to be) an asteroid. Though it would be easier if we go to a near Earth asteroid instead. In the balance of things, I think Mars is still more enticing. Though I'm definitely in the robot probe camp. And I would much rather have people on the Moon again, since my hopeful belief is that trained geologists on the ground for a full lunar day would be more capable than the equivalent cost in robots at understanding lunar geology. (I ask myself though if it's worth the 1% chance of death.)

4 points by stevenjgarner 12y ago

Could Venus be a more enticing option for an upcoming manned mission than Mars? Not having to perform descent and subsequent launch, such a mission presumably could be done for a fraction of the cost of a Mars mission.

dalke 12y ago
There are three possible mission plans I know of for Venus. 1) Venus flyby, like what was planned in the 1970s with Apollo hardware. 2) Orbit Venus, and 3) this one to descend into the atmosphere. For Mars there are four: 1) flyby, 2) orbit, 3) land on one of the Martian moons, 4) land on Mars. The latter has a variant: Zubrin proposed that we can make rocket fuel on Mars and use that for the ascent and/or return. Of these, I don't see why a flyby does anything other than say we did it. Our automated probes are now much more capable than we had in the 1960s/1970s. Though if a human were useful, the Venus is definitely quicker to get to than Mars. As far as I can tell, it's about the same amount of delta-v to get to Mars as Venus, so orbiting either is possible, except the longer flight time for Mars and back means a lot more extra supplies (something like 5kg/day * 14 months?) and more risk of something going wrong. Venus comes out ahead. But what does a human orbiting either planet add that a robotic probe does not? The most often given example is fast response time for a rover, since it's at least a 4 minute lag for Venus and 6 minutes for Mars. I would rather have a dozen slow rovers on the ground controlled from Earth, or a dozen long-term probes orbiting the gas giants than a single one by a human above Venus. In any case, we know we can put capable rovers on Mars. On Venus they tend to melt. This one to descend into the atmosphere of Venus means a return vehicle almost as powerful as what's needed to get someone off Earth. That's going to be tough to solve. Our biggest balloon launched rockets are, I believe, from amateur organizations. OTOH, robots don't need to come back to Earth. Landing on a moon of Mars would combine Mars observations and visual exploration of (what's believed to be) an asteroid. Though it would be easier if we go to a near Earth asteroid instead. In the balance of things, I think Mars is still more enticing. Though I'm definitely in the robot probe camp. And I would much rather have people on the Moon again, since my hopeful belief is that trained geologists on the ground for a full lunar day would be more capable than the equivalent cost in robots at understanding lunar geology. (I ask myself though if it's worth the 1% chance of death.)