I'm bored. Let's plan a manned Venus landing.

[nhnifong]

Wow, everyone taking the easy route out eh? First you need to survive EDL. I would propose some form of two stage re-entry using lifting guidance like the techniques employed by Apollo and Curiosity. This give pinpoint landing accuracy for picking the most hospitable locations on the surface which would be prescouted using probes. This probes would also test techniques for withstanding the surface pressure and harsh environment. Parachutes would give easily enough drag to allow an unpowered descent.

Second is craft design. I would suggest a Bathysphere type design. Good for re-entry (proved by soyuz) withstands pressure well. Allows for a minimal number of facets for acid to cause trouble at. The only blemishes would be for extending legs, and the engine. A single airlock allows egress (more on this later). Comms would be established via a small ruggedized plastic balloon that would carry a wire aloft beyond the worst of the atmosphere. A rover could fold out from the lower regions of the sphere for extra mobility. The sphere would be large with two floors and an engineering section (containing three chemical rockets and a nerva that runs on gas extracted from the atmosphere during Venus Ascent)

EVAing would be less like wearing a spacesuit and more like donning a turn of the century diving suit. It will be very heavy. Maybe the exoskeleton could contain some servos to aid the astronaut?

Power would be supplied by the on board reactor that also runs the NERVA.

The stay would be short and after takeoff the craft would use a Mercury gravity assist to slingshot back to Earth, with a travel time of not more than 300 days. This limits radiation exposure. Th Bathysphere design inherently offers a fair amount of radiation protection due to the structural elements necessary for the atmospheric pressure on Venus.

Supplies would be freeze dried and stored maybe a small supplementary hydroponics lab but Venus is not going to permit any kind of inflatable habitat for growing food.

What do you think? Please give comments and criticism.

I really like many of the features of this lander! It sounds pretty heavy though, but nothing a few chemical rockets docked in orbit can't handle.

I don't think an ascent engine is worth bringing. For starters we could just try a one way trip. The astronaut(s) would work on the surface until supplies ran out and then painlessly commit suicide. Sounds harsh, but there will certainly be some qualified volunteers anyways, and it offers all the same benefits of a manned mission (except sample return)

The nuclear reactor is going to be heavy, and in space, it's going to require some seriously large radiators. Reactors on Earth all use water to cool them, but that's not available in space. The reactor on venus could use the atmosphere for cooling, but since it's very hot to begin with, that's still a huge challenge.

I would go with solar for energy. the panels dont need to be as big because of the closeness to the sun down there. But you still need a ton of energy for your refrigerator system. You still need big radiators in space, but at least in the atmosphere of venus you can use a traditional gas exchange refrigerator, it's just going to be inefficient and eat lots of power. Whether sufficient solar energy can be gathered at the surface dictates whether the design will require another energy source.

Coating the outer surface of the craft with ~50 micrometers of aluminum oxide (ruby) should be sufficient to protect it from the hot acidic atmosphere. It's clear in the absence of impurities, so you can cover the solar panels in it too. Absolutely no metal must be exposed without being coated in aluminum oxide.

On the surface, rather than using an airlock and flexible suits, which introduce many weaknesses where acid can get in and corrode important equipment, ground exploration would be accomplished by driving the entire ship around. The astronauts stay inside at all times. It needs as few moving parts as possible to prevent corrosion. A solid state electrostatic hovercraft which accelerates the dense Venusian atmosphere using charged plates may be possible depending on whether the electrodes can be properly shielded from acid without impairing their functionality.

[dharak1]

Why not some sort of tether? Like a really big balloon in a high part of the atmosphere that lowers a small pod with crew in it to the surface then they get back in get raised up and the rocket takes off from the balloon.

[Brotoro]

People are going on about the nasty acid, but the sulfuric acid in Venus' atmosphere is confined to the clouds, high above the surface (and the acid that rains out of the clouds does not get very low before it evaporates and returns to the clouds). You won't need to worry about acid on the surface. A simple aeroshell will protect your ship from the acid clouds during entry, then eject it lower down and the problem is gone.

Edited June 17, 2013 by Brotoro

[th3shameless]

the real issue would be getting off, with gravity similar to earth and blistering heat; we'll need propulsion which can burn hotter than the atmosphere to takeoff

[ZingidyZongxxx]

I would go with solar for energy. the panels dont need to be as big because of the closeness to the sun down there. But you still need a ton of energy for your refrigerator system. You still need big radiators in space, but at least in the atmosphere of venus you can use a traditional gas exchange refrigerator, it's just going to be inefficient and eat lots of power. Whether sufficient solar energy can be gathered at the surface dictates whether the design will require another energy source.

Actually, less solar energy reaches the surface of Venus because of its dense cloud layer. The clouds block out the sun so much that you can't even see it.

the real issue would be getting off, with gravity similar to earth and blistering heat; we'll need propulsion which can burn hotter than the atmosphere to takeoff

Yeah, I mentioned this before. The atmosphere is extremely dense too, so we would have to deal with more drag. The lander would have to be multiple stages too, since we can't even ascend from Earth in one stage yet.

Edited June 17, 2013 by ZingidyZongxxx

[rodion_herrera]

People do it regularly in Orbiter. I know one guy did a really detailed mission profile once, with a lander, that returned to earth. But I can't find it. I did find THIS in YouTube, but of a Manned FLYBY and no landing, but still quite interesting to watch:

[magnemoe]

I really like many of the features of this lander! It sounds pretty heavy though, but nothing a few chemical rockets docked in orbit can't handle.

I don't think an ascent engine is worth bringing. For starters we could just try a one way trip. The astronaut(s) would work on the surface until supplies ran out and then painlessly commit suicide. Sounds harsh, but there will certainly be some qualified volunteers anyways, and it offers all the same benefits of a manned mission (except sample return)

The nuclear reactor is going to be heavy, and in space, it's going to require some seriously large radiators. Reactors on Earth all use water to cool them, but that's not available in space. The reactor on venus could use the atmosphere for cooling, but since it's very hot to begin with, that's still a huge challenge.

I would go with solar for energy. the panels dont need to be as big because of the closeness to the sun down there. But you still need a ton of energy for your refrigerator system. You still need big radiators in space, but at least in the atmosphere of venus you can use a traditional gas exchange refrigerator, it's just going to be inefficient and eat lots of power. Whether sufficient solar energy can be gathered at the surface dictates whether the design will require another energy source.

Coating the outer surface of the craft with ~50 micrometers of aluminum oxide (ruby) should be sufficient to protect it from the hot acidic atmosphere. It's clear in the absence of impurities, so you can cover the solar panels in it too. Absolutely no metal must be exposed without being coated in aluminum oxide.

On the surface, rather than using an airlock and flexible suits, which introduce many weaknesses where acid can get in and corrode important equipment, ground exploration would be accomplished by driving the entire ship around. The astronauts stay inside at all times. It needs as few moving parts as possible to prevent corrosion. A solid state electrostatic hovercraft which accelerates the dense Venusian atmosphere using charged plates may be possible depending on whether the electrodes can be properly shielded from acid without impairing their functionality.

Note you can make an NERVA with TWR higher than one and good trust. You could perhaps use an nuclear ramjet to as soon you get up in speed and out of the dense atmosphere. Might considering balloons in the heavy atmosphere, but not sure if it would survive.

Mission profile would be an lander with an landing stage with the cooling and an lab airlocks and suits. This would be left on ground, the astronaut(s) and samples would leave for the accent stage and get out.

Now an sample return mission would be more realistic and would have the same issues however scaled down.

Soft land a craft with perhaps two rovers, they collect samples, return them to craft, they are transferred to accent stage who leaves.

[Kerbface]

Magnemoe, why are you using the word "an" in place of the word "a" in so many places?

[metaphor]

Note you can make an NERVA with TWR higher than one and good trust. You could perhaps use an nuclear ramjet to as soon you get up in speed and out of the dense atmosphere. Might considering balloons in the heavy atmosphere, but not sure if it would survive.

I was thinking something like this for a lander with a rigid envelope balloon. By pumping gas in and out of the tank you can change the buoyancy.

NERVAs could be used to get out of the atmosphere but the technology is probably farther away, that's why I only used them in the interplanetary stage.

[nhnifong]

Does anyone know the ∆V requirement of an LEO to Venus transfer burn? I'm guessing its the same as mars at about 4.5 km/s but I can't find it, also similarly to Earth, ascent to low venus orbit (without balloons) should be about 7 km/s plus 4 or 5 to gravity and drag.

that's a total of at least 15 km/s. starting in LEO. We're talking about a vehicle the size of like three Saturn V rockets in orbit

[metaphor]

Does anyone know the ∆V requirement of an LEO to Venus transfer burn? I'm guessing its the same as mars at about 4.5 km/s but I can't find it, also similarly to Earth, ascent to low venus orbit (without balloons) should be about 7 km/s plus 4 or 5 to gravity and drag.

that's a total of at least 15 km/s. starting in LEO. We're talking about a vehicle the size of like three Saturn V rockets in orbit

Transfer to Venus is a little easier than transfer to Mars. LEO to Earth escape is about 3.2 km/s, and using the Oberth effect you need only a little bit above that to get to Venus or Mars. Venus is about 3.5 km/s and Mars is about 3.6 km/s from LEO. The trajectory browser from NASA is pretty fun to look at for things like this. Getting from Venus transfer to LVO is about 3.3 km/s. So at the very least the interplanetary stage needs 3.5 + 3.3 + 3.3 = 10.1 km/s. I used a nuclear thermal rocket for interplanetary burns with an Isp of 1000s, which is actually not too far off in terms of technology. With that kind of engine you don't really need that big of a rocket in LEO. I used a delta-v calculator to figure out how big the rocket stages would have to be.

You would not take off with a rocket from the surface of Venus. Going through that thick atmosphere would take a ridiculous amount of delta-v, something like 50 km/s. But from near the top of the atmosphere it would only be a little more delta-v than the 7 km/s orbital speed. (See my post on page 2 for what I thought the mission architecture could be.)

Edited June 18, 2013 by metaphor

[th3shameless]

You would not take off with a rocket from the surface of Venus. Going through that thick atmosphere would take a ridiculous amount of delta-v, something like 50 km/s. But from near the top of the atmosphere it would only be a little more delta-v than the 7 km/s orbital speed. (See my post on page 2 for what I thought the mission architecture could be.)

ya, definantly a balloon or a rocket powered glider of some sort to get off would be needed

[Brotoro]

I don't know if we can build refrigeration systems that can pump heat to the 735K temperature of Venus' atmosphere. If not, I suppose the lander could carry a big tank of liquid helium down to the surface and use it to cool everything down until it's used up. I wouldn't imagine it will not give you a great duration stay.

Of course, if we can make a flexible balloon material that can withstand 735K, we can be filling the balloon with the hot helium we vent out of the cooling system as we get near enough to the end of the stay, then ride that balloon as far up as possible. The rest of the way up (and the flight down) could be powered by nuclear jet engines (developed in the 50s and 60s but never used on Earth).

If you want to do an EVA (and if not, why are you sending people instead of robots?), it will be very tough. Venus' atmospheric pressure is equivalent to what you'd find at an ocean depth of one kilometer on Earth. Our most extreme diving suits have only managed to reach 610 meters, and those are VERY heavy, which is not so much of a problem underwater, but will be on the surface of Venus. These diving suits are like wearable submarines. Plus they'll need to be even heavier to add insulation and refrigeration equipment...and a powered exoskeleton to move the damn thing. It would be like a little human-shaped tank. Not really what I'd call an EVA.

But maybe you could have a bell-shaped chamber on the bottom of your lander that makes a tight seal to the ground (maybe because it has an alloy around the rim that softens enough at 735K)... Place this against a flat area of the surface and start pumping the Venus air out of it. Venus' atmospheric pressure would mash it down powerfully to the surface by the time you pump out the Venus air and pump in some cool oxygem-helium mix at a lower pressure. Then you can open up the top airlock and stand on the surface of Venus naked if you wear insulated booties. But a cooling suit would be advised. Pick up some rocks, drill a sample, plant a flag, pee on the dirt, whatever. Then get back in the main part of the ship for liftoff, because the bell will get detached an left behind.

[th3shameless]

realistically, we'd probably be better off trying to put a floating base in the upper atmosphere. there temperatures are a comfortable ~20c and pressure is around earth pressure. the only real protection needed would be from the sulfuric acid and occasional heat.

pee on the dirt

LOL, gotta claim the land somehow

[Kilmeister]

"A few small drops for man, On giant piss for mankind"

Maybe not as elegant, but even other animals would get the message.

[th3shameless]

"mission control the piss has landed i repeat the piss has landed"

[nhnifong]

I'm replying to your first post here. somehow I missed it until you pointed it out.

Btw, thanks for the excellent link to NASA's trajectory browser.

Since you need about 7-8 km/s delta-v to get to low Venus orbit, you would have to use a different return rocket that is waiting at 50 km. At 50 km altitude, the pressure is 1 atmosphere and the temperature is about 20 degrees Celsius. The return rocket would use a big inflatable balloon to stay up at that height. It would have to be a pretty big multi-stage rocket, with a very small capsule, Dragon-size or smaller. Once the crew used the return rocket, they would meet with the interplanetary stage and deep space habitat in low Venus orbit, and use them to return back to Earth.

So, you've got a balloon-suspended ascent rocket waiting at 50km, and the deep space hab waiting in LVO.

Wind speeds on venus are in the range of 100 to 300 km/h (I don't know aout the 50 km alt. specifically, but it's probably close). That floating balloon is going to be long gone by the time you attempt to go back to it. You might want to wait for it to go all the way around the planet.

Taking a hint from our Eve landings, we could choose a high altitude landing site to save on fuel. Maxwell Montes is 11 km high, and 63° north of the equator.

At this latitude, assuming the wind just blows around the planet all the the same direction in all places at 250 km/h, the balloon would make it's way back to it's starting point in only 72 hours. But I think it's actually slower at more northern latitudes, so it might be that the wind takes up to 150 hours to make a circuit around the planet no matter the latitude, the same time it would take at the equator.

[nhnifong]

About the refrigerator, A concept design for a sterling cooler has been designed for a small Venus rover. The working fluid is helium and It is capable of pumping 100 W of heat across the barrier at a cost of 240 W of electrical power.

The temperature at the peak of Maxwell Montes is about 380 °C. So in order to achieve a 20° internal habitat temperature, a 360 °C differential must be maintained. The thermal conductivity and the surface area of the habitat will roughly determine the wattage of heat that will be conducted into the habitat at this temperature differential.

Let's assume the habitat is a sphere with an outer diameter of 4 meters, insulated with 20 cm of silica aerogel. The thermal conductivity of aerogel is about 0.02 W/(m*K). If I'm doing the math right, then that's 0.02 W/mK * 360 °K / 0.2 m, giving 36 W/m². I believe this is the conductance per square meter. Our habitat has a surface area of 50.26 meters, we have to pump out 1806.36 W of heat. Our heat pump's efficiency is 0.44, so we need a 4112.18 W power source to drive it.

I leave it up to you guys to figure out how to make a 4 kW power source on the surface of venus, (well on Maxwell Montes at least)

Edited June 19, 2013 by nhnifong

[sai99999]

Considering Venus is so hot, you could use a steam-based generator.

How much power it would make, I don't know, but probably not 4kW. Maybe have good batteries with lots of electricity? But just having batteries won't have enough power.

Or wireless charging. Perhaps the refuelling station can have some solar cells or some other type of electricity generation, beamed down to the lander.

But still, doesn't the refuelling station need cooling too? I would expect the station to be much bigger than the lander, and likely needs more power.

Wireless charging from Earth is viable, but it would take several seconds for electricity to come across such a huge space. On-board batteries should be important.

EXCEPT that wireless charging doesn't work as well at such a distance.

Much speculation is required.

[Bunsen]

Taking a hint from our Eve landings, we could choose a high altitude landing site to save on fuel. Maxwell Montes is 11 km high, and 63° north of the equator.

At this latitude, assuming the wind just blows around the planet all the the same direction in all places at 250 km/h, the balloon would make it's way back to it's starting point in only 72 hours. But I think it's actually slower at more northern latitudes, so it might be that the wind takes up to 150 hours to make a circuit around the planet no matter the latitude, the same time it would take at the equator.

With wind speeds like that, I think you'd be better off with a nuclear-powered winged aircraft flying circles (or just keeping station) above the landing site. That comfortable 50km altitude is right in the middle of Sulfuric Acid City, though, so have fun making that engine last more than a few minutes. You might be able to get something to last a while above the clouds; the pressures there aren't out of line with high-altitude aircraft or balloons here on Earth. The low temperatures would make nuclear thermal propulsion pretty efficient.

[falofonos]

Not the strongest material but glass is resistant to sulfuric acid, a fiberglass rigid balloon at whatever altitude you can happily maintain tethered to the surface with turbines for propulsion and or electrical generation. From this balloon you drop some form of unobtanium chimney stack to your landing site. Using power from the wind or your nuclear reactor you can pump atmosphere up to some point above you providing a good volume of gas to vent heat into (i'm sort of stealing this from a book by http://en.wikipedia.org/wiki/Jack_McDevitt ) .

If the chimney isn't practical then a heat pipe arrangement may work, although finding a pipe material that can survive the environment while providing thermal conductivity needed would be tricky.

Stirling engine coolers coupled with large scale Peltier coolers may work to keep your habitat survivable.

While the idea is completely insane, my main concern would be about ground stability. A balloon is pretty crazy but at least you're unlikely to have to deal with your landing gear sinking into the molten lead, or just sinking through the crust altogether.

The problem of supplying such a long duration mission can be overcome with multiple launches of food, oxygen and toilet paper but the whole endeavor is going to be quite expensive for little scientific return.

At least there's verified water on Mercury to use for in place supply.

[The Jedi Master]

An idea: What if we used aerospikes (or they're real-life equivalent), a la Eve landers in KSP?

[nhnifong]

I think you're onto something there falofonos, maybe we could power this thig with a couple of ordinary wind turbines

[Alfondoo]

4kw wind turbine, if the atmosphere is more dense then with more force pushing the blades you could probably scale it down and still achieve 4kw. The only problem is trying to fit it into a constrictive design, wind turbines aren't small...

Potential for deployable turbines?

Edited June 21, 2013 by Alfondoo

[Kamsko]

Basically what the title says. Can we KSPers get around the whole thing about an acidic atmosphere and lots of volcanoes and lots of pressure and how hard it is to get beck, etc.? We will find out. Also, feel free to add whatever near-future tech you may wish.

First, I think we need to come up with a proper material. I would say diamond, but really, have you ever heard of a rocket made out of diamonds? Keep weight in mind, too.

Begin!

So if we aren't taking into account literally every Venus defining feature, are we not landing on Venus?