Six Minutes of Terror - Landing Humans on Mars

OriginalArlen writes "Universe Today has a fascinating article discussing the difficulty of executing EDL (entry, descent, landing) on Mars for vehicles bigger than MER, Viking and Pathfinder, and the challenges for manned craft in particular. Airbags can't be used for obvious reasons, but the atmosphere is too thin to be used for parachutes or aerobraking by large heavy vehicles. The stronger gravity (compared to the moon) makes an Apollo-style powered descent impossible. The best current idea is a huge inflatable torus called a hypercone: 'Imagine a huge donut with a skin across its surface that girdles the vehicle and inflates very quickly with gas rockets (like air bags) to create a conical shape. This would inflate about 10 kilometers above the ground while the vehicle is traveling at Mach 4 or 5, after peak heating. The Hypercone would act as an aerodynamic anchor to slow the vehicle to Mach 1.'"

Comments

Parachute?

[MankyD]

The Hypercone would act as an aerodynamic anchor to slow the vehicle to Mach 1.'"

Some care to elaborate on the difference between this and a parachute?

Re:Parachute?

[Waffle Iron]

The atmosphere on earth is dense enough to slow down a capsule or winged orbiter to below hypersonic speeds just using the shape of the vehicle itself. Then the parachutes can be deployed without them getting burned up or ripped to shreds by a hypersonic gas stream.

The real question is

[Rosco P. Coltrane]

Do we really need to land heavy stuff on Mars? "Something heavy" here means some spacecraft with human creature comfort (you know, a hull, life support systems, etc... in order to keep wetware inside alive). However, there is no need for manned flight to other planets anymore: probes do a much better job more easily, at a fraction of the cost, and a probe's survivability is much less of an issue.

Probes are an extension of humanity's collective intelligence, and they bring back to humanity at least as much data as a real, flesh and bone human. So why send humans at all? Of course, if we're talking about colonizing Mars for good, there's some terraforming to do, but heavy machinery isn't necessarily required for that either, and it's not going to start within our lifetime anyway, and the planet won't be ready for us in 200 years minimum anyway.

I say forget about hauling big stuff over to Mars. The only folks who care are prez Bush, for demagogic purposes, and people who think watching a Neil Armstrong type character utter some silly piece of wisdom when setting foot on a planet is the pinnacle of human space exploration. What we need is more research into nanotechnology, so probes get smaller and lighter, and educating people.

Re:The real question is

[R3d M3rcury]

[...] probes do a much better job more easily, at a fraction of the cost, and a probe's survivability is much less of an issue. Probes are an extension of humanity's collective intelligence, and they bring back to humanity at least as much data as a real, flesh and bone human. That's always the question I have. Do Probes do a "better job"?

Now, I'll admit I disagree with your opinion on sending people to Mars. But I agree with the basic tenets about the expenses involved--probes are definitely easier and cheaper. The question I always have is--do you get better science when you send scientists versus sending probes?

I'm not sure that question has ever been explored. Do we know more about the Moon than the Soviet Union because we sent astronauts versus robotic probes? I know we brought back a lot more moon rocks (Apollo brought back 381kg versus the Luna missions' 0.325kg), so there has to be some value there. The Soviet Union's 2 Lunakhod rovers travelled 47km, whereas the 3 LRVs transported astronauts 90km (in comparison, Spirit and Opportunity together have travelled about 18 kilometers). Obviously, the more you see the better chance you have of making a discovery.

Personally, what I think might be a cheaper way to go is "telepresence." Rather than sending people to land on Mars, you send people to orbit Mars. You then send down a batch of rovers which can be controlled by the people in orbit. You'd probably be able to achieve much better bandwidth between a probe on the planet and a person in orbit (versus a person on Earth), allowing for 3D cameras with very high resolution. "Bionic" hands on a rover could pick up interesting things that the astronaut sees and take them to a launcher which would send them up to the astronauts in orbit. There'd be negligible signal delay, allowing for real-time images and decision making by an astronaut driving the rover along the surface. After awhile, the ship with the people returns to Earth with tons of new data about Mars and leaves the rovers on Mars.

The idea is to get the brains closer to the thing they need to study. While I agree that we don't necessarily need to send people to walk around on Mars (though I think that's a good goal), I'm not sure 50-300 million miles away is a good idea either.

Re:The real question is

[khallow]

Even if there is a huge disaster on Earth than destroys much of the infrastructure, it is not going to destroy all knowledge. So we are not going to go back to pre-industrial life. It was too easy to create the industrial age in the first place. There will be plenty of people able to reboot the iron age, and progress from there, given current knowledge, will be swift.

It won't be "current" knowledge, it'll be whatever knowledge survives. And the destruction of law, society, and other infrastructure isn't something that gets fixed merely because you know what you should be doing. A number of of today's societies don't bother to improve themselves even though the knowledge is easily available. In any case, it'll be a period of decades, perhaps centuries when the human race won't be progressing but just covering old ground. And this will happen every time society collapses.

Message for Humanity

[sehlat]

all these worlds are yours
except mars
attempt no landing there

Re:Impact

[iknownuttin]

Landing at mach one still sounds pretty fast -- better aim for water! Oh, wait ...

LOL. I was once in Aruba and I rented a one of those Ski-doo things. I revved the fucker up to 55 and went off. Then I made a turn. Well, G-Forces took over and I went flying across the ocean. Now, you'd think water was soft (I know YOU don't because of your post, but others...), but when I hit it, it felt HARD. So, I went again, and did the same thing...well, look at my user name...duh! (I live up to it, man!)Oh, the water was still fucking hard at 50+ MPH!

Re:So you hit the surface ...

[Lee148]

Dude, read the article.

Why not a parachute

[ookabooka]

The Hypercone would act as an aerodynamic anchor to slow the vehicle to Mach 1.'"

So. . a parachute then?

On a serious note, why not use a parachute? They've been used before on many missions to mars to slow the vehicle down before the retrorockets fired. I mean I understand the hypercone would work too, but I dont understand why a larger and/or more parachutes wouldn't. Then again I'm no fluidynamicist (is that a word because it sounds really really cool).

Won't ever happen

[texwtf]

The original moon missions involved _enormous_ rockets. Even if you could land on Mars what is the likelihood you would be able to transport rockets big enough to get you back off there?

Oh yeah, and have it work after being dropped from outer space.

Maybe if they used nuclear power to lessen the wight somehow, it _might_ be possible. Otherwise it's just a long one way trip with a slow cold end.

Re:Mach 3 Chute

[Lumpy]

A chute opening at Mach 7 on mars is very different to a chute opening at Mach 7 here on earth. the atmospheric density is so much lower that it would be very feasable.

They already have designs that work, simply triple them up. They are also going to haveto do a powered decent no matter what, you are not going to get a plane to get any bite in that atmosphere at all (although a delta wing would be able to do breaking maneuvers lust like the shuttle does so it might not be a bad idea.)

Honestly they will have to send a robotic test mission like they did with apollo unless they are willing to accept a "oops" moment as we hear the news that 7 astronauts plummeted to their death because someone divided by zero.

The support ship will have to be huge, and the dry run with the support ship is not only a great idea, but will also tell us if the astronauts will get there with only one left and all the rest for some reason went for a walk and will be "back real soon now"

Re:Why mess with Mars?

[geekoid]

"There is no real reason to send a manned flight to Mars. None."
wrong. More in a moment.

"You would need to send enormous amounts of gear, several hundred tons of water
and food and air enough for the journey, the time spent on the planet and
the trip back. "

and

"You would need a "mother ship" and at least two 'landers' with return
capability. In addition, a habitat for the humans. If you think you are a
treehugger, imagine the colossal amounts of resources needed to get there
and the environmental impact on Earth, just to start this type of endeavor."

Because it's hard is why it should be done.

"Think people. That grey matter is supposed to be used."
You first. I mean really.
Now back to the first part...Why?

1) The resulting spin off products will create new spin off companies.(The taxes returned from the companies that sold products created from the Apollo missions had gotten 13 time the return in taxes then the Apollo cost.)

2) New technologies and RnD help drive science.

3) This would almost certianly be a global project. Big Global Projects can help bring people together.

4) The environmental research and technology would help us develop a better understanding of enviromental controls on earth.

5) So we can stick out our just chest and say "Been there, where to next?" Not to consider the emotional impact on people is foolish.

6) More experience with space flight is another step towards off world mining and colonies.

Yes, there should be robotic exploration as well.

Personal, I would send drop ships to drop supplies before humans left for mars. Complete satellite arrays, rover to scout out select landing zones. Maybe even send the returning vessel ahead. Pack it with what they will need to return, and nudge it to mars. No rush, you can send it a couple of years ahead of time. You could also send some different landing tests.

Re:Same way they land on Earth

[terrymr]

The temperature of nothing is nothing - true. But nothing doesn't absorb heat either.

Re:Why drop?

[SEWilco]

It's not easy to create a winged vehicle because the thin atmosphere means the wings have to be huge. But they can't use huge wings because they would first have to withstand orbital-speed entry heating and deceleration. If the wings aren't huge then they have to fly very fast in order to get enough lift. But there is no runway so they have to land slowly with huge wheels...or land on rockets.

Or start shipping the human living quarters, with robots assembling it, and putting all the packing peanuts in a crater for use during the landing.

Re:Make up your mind

[evilviper]

Deploy a large enough glider, and you will glide.

Okay, what does a glider that can carry several tons look like (on earth)? The ones that can only carry a single human's weight are pretty damn large.

Now, since the atmosphere on Mars is 1% what it is on the Earth... Have fun building your glider two orders of magnitude (100X) larger than normal, and then finding a way to launch that ridiculously huge thing from the Earth.

Re:Space ladder?

[Anonymous Coward]

My thoughts exactly.

I seem to remember one of the obstacles to an Earth space elevator is that if it snapped it would wrap itself around the planet a couple of times. Seems Mars could be a good place to test one if we can work out the logistics of transporting it.

Not to mention we'd get some layman-friendly practical research done which can only be good for funding.

CAPTCHA: "Dismount" well, quite.

Lean in to it..

[up2ng]

Grasshopper.

Try that on a motorcycle and you WILL see the difference between Asphalt and (soft cushy) water