Venus surface sample return mission?

[Der Anfang]

I'm talking about a real life scenario, here. It probably seems silly to ask, considering all of the circumstances. But, let's put the silliness aside. What exactly would it take for an unmanned surface sample return mission from Venus back to Earth? Is that even possible with current, modern technology? If so, what kinds of numbers are we looking at, here? And what exactly would you need to do? How would the mission be conducted?

[Joonatan1998]

1. Venus is almost as large as earth, so getting in orbit requires an huge rocket.

2. Rockets don't react well to the conditions at surface.

3. High pressure makes rocket engines almost useless.

Small lander takes a sample, then returns with a balloon.

Rocket uses a huge ballon to stay in upper atmosphere.

The sample return balloon is somehow picked up.

The rocket returns to orbit.

A probe picks the sample up from low orbit and returns it to earth.

The re-entry fails, sample lost.

Edited June 15, 2015 by Joonatan1998

[Dangerous_Beans]

back in the 50's or 60's, they accidentally launched "man-hole cover" into space using a nuke. basically, they accidently made a Verne gun/space gun (https://en.wikipedia.org/wiki/Space_gun). maybe a probe that bores a shaft to use as a barrel, some explosive (small nuke) as propulsion and another craft to retrieve the sample would work?

still has the problem of the atmosphere and gravity, but seems like a potentially practical solution.

edit: ok, the plate was the Pascal B test, and probably burnt up on ascent (i love that problem!), but the basic idea clearly works. the payload would just need better aerodynamics.

Edited June 15, 2015 by Dangerous_Beans

[AG5BPilot]

A real life Venus ascent would likely be quite challenging. KSP's Eve is a cakewalk be by comparison.

While Eve's atmospheric pressure of 5 atmospheres causes Kerbaldom severe rocketry problems, the real life Venus's atmospheric pressure is a staggering 92 atmospheres. Pushing a rocket upwards through that soup would require a lot of energy -- or a completely different ascent strategy.

And you need to build your entire spacecraft like a submarine, with a reinforced pressure hull to keep the whole thing from imploding.

However, dealing with the atmospheric pressure is probably the EASY part. The killer is the temperature -- around 462 degrees Centigrade (862 Fahrenheit). Typical solder melts at 183 C or 361 F, so you're going to have trouble with electronics -- and probably everything else, too.

If you can solve the temperature problem -- and that's a HUGE "if" -- I imagine you would want to make use of the dense atmosphere to ascend by using either wings or some sort of balloon. On the other hand, getting down should be very, very easy. Terminal velocity is low enough to land softly without propulsive landing or even parachutes. (The earliest Russian Venera Venus surface probes died before reaching the surface because the descent under parachute took so long that the batteries were exhausted before reaching the surface. Later Venera probes used parachutes to slow down -- then cut the chutes 50 km up and floated down to a soft landing without a parachute.)

And did I mention the atmosphere contains sulfuric acid clouds? Yet one more challenge to be overcome.

Given the extreme temperatures, if you wanted a surface sample, it would need to be a very fast mission. No loitering on the ground. We know how to get down -- pre-chill the spacecraft before deorbit, brake in the upper atmosphere, then use very low drag descent systems to get down quickly. Slowing down is easy -- imagine the overpowered KSP airbrakes -- except it really works on Venus.

Once down, almost immediately you'll need to grab your surface sample, and ascend back up. Probably some sort of lighter than air system would be best. An inflated balloon should be able to get you up in the atmosphere pretty quickly, above a lot of the pressure and heat. Then some soft of rocket or rocket/plane combination to get you the rest of the way to space and give you orbital velocity.

In KSP, almost every problem is a matter of getting enough delta V. On Venus, however, survival is the biggest problem.

[Streetwind]

You might want to ask a moderator to move your thread to the Science Forum. You'll probably get much better answers there.

But to give you an idea what you're asking:

Take Eve, in KSP. Ponder how difficult it is to land on Eve and return, how much the engines are penalized. Realise that Eve has about 5 times the atmospheric pressure of Kerbin. Now visualize the fact that Venus has 92 times the atmospheric pressure of Earth. Oh, and by the way, that air is boiling at 500°C, and it is raining concentrated acid. Which is also boiling.

Abandon all hope, ye who land here. You will not return.

[Hcube]

This would fit better in the Science Labs forum...

Anyway i really like Joonatan1998's idea of a baloon to get the small lander back up. However having another huge baloon to keep the main rocket in uoper atmo seems hardly feasible... How would you keep it in the same spot with the winds, and how would you pick up the lander ?

[eddiew]

Small lander takes a sample, then returns with a balloon.

That's pretty much the only option right there. The thickness of the atmosphere would mandate an unpowered ascent. Handily, there's a nice band of the high Venusian atmosphere that's round about 1atm pressure, above the acid clouds and rain, and a comfortable room temperature - easy place to hang around for a pickup.

Although admittedly the mechanics of that pickup would be hard as hell, and you'd need a balloon that could survive the surface conditions Assuming you had the materials for the job, it might be possible to produce a very small robot lander that could balloon itself to the very brink of space, then kick itself up into orbit for rendezvous with a transfer stage that never went into the atmosphere at all.

Edited June 15, 2015 by eddiew

[KerikBalm]

Basically, you'd want to get this thing to Venus, and have it hanging from a baloon:

https://en.wikipedia.org/wiki/Pegasus_%28rocket%29

Then you'd want your lander to go down, take a sample, and balloon up and meet with the rocket-balloon (so some sort of electric fans to allow it to navigate, ie, a blimp)

Now that balloon would need to lift the pegasus rocket up pretty darn high, well above 1 atm, as the pegasus launches from much less than 1atm on earth (and also a couple hundred m/s already).

Luckily, the atmosphere of venus is denser at the same pressure (CO2 has a higher molecular weight than N2), so you'll have more lifting power.

You may want to modify the pegasus to make use of an air augmented rocket stage... I'm not sure how usefull it would be at high altitude, but if the rocket is dropped lower into the atmosphere, then it becomes more desireable.

Then your payload with the sample needs to do an orbital rendevous with something in orbit of venus to actually get back to Earth.

Not very feasible

[waterlubber]

If only we could pump all the CO2 from Venus' atmo to Mars. I like Mars better.

[cryogen]

Here's a NASA study on this idea:

"Venus Surface Sample Return: A Weighty High-Pressure Challenge"

http://ntrs.nasa.gov/archive/nasa/ca...0010003946.pdf

Since Venus is a large planet (Earth-size), you'd need quite big an ascent rocket to get off of it. Even bigger than a Mars sample return. In the concept I linked, they try an Apollo-type mission, with a separate Venus orbiter/return vehicle, and Venus lander/ascent vehicle. The ascent uses three stages of solid rocket, and gets launched from a balloon, inflated with helium from tanks. I guess, given the very thick atmosphere, a giant balloon would be cheaper than a rocket powerful enough to push through the soup.

Getting a sample-drilling machine to work at the surface would be a major challenge. Silicon IC's won't work at the high temperatures of the Venus surface. You'd need either a very heavy, inefficient refrigeration system, or a very fast surface mission packed with ice, or a new / exotic type of high-temperature electronics.

The overall mission size isn't bad -- they think it could be launched with a single Delta IV M+ (the single-core with SRB's -- smaller than the three-core 'heavy'. That's less than 13 tons in LEO).

Edited June 15, 2015 by cryogen
minor typos / OCD

[lajoswinkler]

back in the 50's or 60's, they accidentally launched "man-hole cover" into space using a nuke. basically, they accidently made a Verne gun/space gun (https://en.wikipedia.org/wiki/Space_gun). maybe a probe that bores a shaft to use as a barrel, some explosive (small nuke) as propulsion and another craft to retrieve the sample would work?

still has the problem of the atmosphere and gravity, but seems like a potentially practical solution.

edit: ok, the plate was the Pascal B test, and probably burnt up on ascent (i love that problem!), but the basic idea clearly works. the payload would just need better aerodynamics.

Lower atmosphere of Venus is a supercritical fluid. It's not gas, it's not liquid. It's kind of both in the same time. You don't fire anything through such fluid. Aerodynamics breaks down in such environment.

The only thing applicable would be an aerostat, but good luck making one that could withstand the pressure. I'd compare it to making a vacuum baloon on the surface of Earth, but worse.

[Nibb31]

back in the 50's or 60's, they accidentally launched "man-hole cover" into space using a nuke.

That's a bit of an urban legend. One of the people on the team calculated that the shaft cover of the nuclear test would be launched into space, however chances are it was obliterated during the test.

Edited June 15, 2015 by Nibb31

[annallia]

Rocket uses a huge ballon to stay in upper atmosphere.

The rocket returns to orbit.

Wasn't that a Lost in Space episode?

[Stargate525]

That's a bit of an urban legend. One of the people on the team calculated that the shaft cover of the nuclear test would be launched into space, however chances are it was obliterated during the test.

It wasn't obliterated. They got one frame of it in the air, intact and moving. Torn apart during the flight, maybe, but not obliterated by the blast.

[Shpaget]

They calculated it could reach just about escape velocity, not that it would escape (Earth or destruction).

[Voyager55]

I imagine something like a ballistic missile that is lift to a high altitude by balloons, where it can be launched to avoid the brunt of the thick atmosphere.

[11of10]

Or land an extremely simple mechanical computer, robustly built to survive long enough to collect the samples and send them on their way up.