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Venus sample return faces extreme challenges beyond Mars missions - the 90x Earth's atmospheric pressure and 450°C surface conditions make rocket launches nearl
by ethan_smith 1y ago
Venus sample return faces extreme challenges beyond Mars missions - the 90x Earth's atmospheric pressure and 450°C surface conditions make rocket launches nearly impossible, while sulfuric acid clouds would rapidly degrade balloon materials. The energy requirements for escape velocity from Venus are also substantially higher than Mars.
- mattashii 1y agoWouldn't it be possible to float teflon balloons (without ever descending to the surface), and use those to carry a launch platform? Samples do not need to be surface samples, the atmosphere itself seems quite interesting already. And note that you may be able to "fish" for samples from an atmospheric floating platform; there is no specific need to get all the way down to the rocks with your rocket.
- IgorPartola 1y agoI thought the atmospheric conditions there were also quite violent.
- TeMPOraL 1y agoThat depends on the layer; there's apparently one that's quite nice, and there's been some work scoping a possible manned mission there - IIRC, there's even some ISRU possibility due to useful chemicals being in layers immediately below.
- OhMeadhbh 1y agoVenus Express did aero-breaking to go into orbit in 2005(?). I don't think it was configured to scan its surface for microbes afterwards, maybe we could add something like that for later missions. IIRC, there's only a thin layer of atmosphere where we think the microbes live, and I'm not sure if VE (or future missions) descended to that layer during aero-breaking, but it's an idea.
- pavel_lishin 1y ago> And note that you may be able to "fish" for samples from an atmospheric floating platform; there is no specific need to get all the way down to the rocks with your rocket. That never even occurred to me! That's a brilliant idea.
- arp242 1y agoLots of things are east to imagine in principle, but actually doing them is just so much harder. There are so many practicalities you run in to. The first from the top of my head would be the required length and sheer weight of the cable attached to that Teflon balloon, to say nothing of the weight of the balloon itself or its contents. Speaking of which, actually keeping the contents in that balloon might also be surprisingly tricky. You need to drag that all the way to Venus, then decelerate enough to stop all that mass, then accelerate that again to come back to Earth, before decelerating to land here. Even without any extra weight that's actually a huge challenge due to the amount of fuel required. There's a reason none of the Mars rovers have come back.
- pavel_lishin 1y agoThe balloon wouldn't contain anything except a gas that's more buoyant than the Venusian atmosphere at the desired height, and maybe we can use the atmosphere itself, just heated up - similar to how hot air balloons work, except presumably fully enclosed. Not to say it'd be easy, but certainly easier than landing & returning.
- perihelions 1y agoAtmospheric sample retrieval—not from the surface—seems doable. > "90x Earth's atmospheric pressure and 450°C" — becomes Earth-like conditions at higher altitude > "while sulfuric acid clouds would rapidly degrade balloon materials" — Teflon coatings are a solved problem; JPL did coupon tests[0] > "The energy requirements for escape velocity from Venus are also substantially higher than Mars" — True, but you'd only need to launch a tiny, dumb payload into orbit, to rendezvous with the return craft. Like Apollo, sample returns aren't one monolithic spacecraft that does the full round-trip; think the Apollo Lunar Ascent Module, but, for ants [0] https://sci-hub.se/10.1016/j.asr.2007.03.017 https://sci-hub.se/10.1016/j.asr.2007.03.017 ("Prototype design and testing of a Venus long duration, high altitude balloon") > "Although the expected sulfuric acid concentration at Venus is expected to be in the range of 75–85%, tests were conducted up to 96% to understand our design margin. The material itself was found to be unaffected by prolonged exposure to all concentrations of sulfuric acid up to a temperature of 70 °C. Adhesively taped seam samples did show some discoloration at the tape edges, but there was no evidence of acid penetration into the joint using blotter paper on the inside surface. This test confirmed that the cover tape adhesive was indeed resistant to sulfuric acid as predicted and can support a long duration balloon mission at Venus." edit: I totally forgot—the Soviets already demonstrated that, in the 70's: https://en.wikipedia.org/wiki/Vega_program#Balloon https://en.wikipedia.org/wiki/Vega_program#Balloon
- OhMeadhbh 1y agoAlso, we could use this as an excuse to have a moon base: when we get sample returns, it's better to have them land on the moon and studied there instead of risking the sci-fi scenario of interplanetary bacterial overlords infecting earth. (Yes, I know the chances of that are low, but I really want a moon base since watching space:1999 as a kid, so I'm just using this as a justification for spending other people's taxes.)
- pavel_lishin 1y agoWhich is why I specified atmospheric sample returns.
- rekrsiv 1y agoWhat if we pushed an asteroid into the planet and collected material from the explosion from orbit?
- TeMPOraL 1y agoEasier to start with an atmosphere-less moon - you need a smaller rock. Also been done. Also, in a way, we've been doing it since before space travel, because such material occasionally reaches Earth's surface in form of meteorites. But that's of course using naturally occurring impactors.