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.'"

Why land?

[Ecuador]

We don't really have to land the large vehicle. Getting within transporter range should be enough.
Oh, wait...

Re:Why land?

[Tablizer]

We don't really have to land the large vehicle. Getting within transporter range should be enough. Oh, wait...

Were you talking into your mouse when you said that?
     

Re:Why drop?

[Glonoinha]

Bunch of NASA whiners must have replaced 'The Right Stuff' through worthless politically correct hiring practices - this new generation of 'engineers' and 'rocket scientists' have forgotten history and thus are being forced to re-invent the wheel. The logistics of these landings were worked out years ago - as you can plainly see in this simulation [frontiernet.net].

Re:

[IAmTheDave]

Or, they could get off their duffs and figure out this whole "gravity" problem once and for all. Oh, "it's a bend in space-time"... Well unbend it already!

Re:

[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

Impact

[eck011219]

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

Re:Impact

[Spy der Mann]

Landing at mach one still sounds pretty fast -- better aim for water!

Don't worry! We'll just tell Quaid to start the reactor [wikipedia.org]. Oh, wait...

Re:Impact

[HTTP Error 403 403.9]

Don't worry! My method will get them down in one piece. You wanted them alive? Oh, wait...

Re:Impact

[stuktongue]

You bring up an interesting idea.

This is where design validation comes in. For those not familiar with this term in the context of system engineering (and, in particular, system engineering of complex aerospace/defense systems), design validation generally refers to the activity whose purpose is to show that a design actually meets the customer's needs (i.e., that it is a 'valid' design). The effort takes design requirements into consideration, of course, but should also make use of system modelling based on the design, among other inputs.

Assuming the statement of work includes support for design validation, and the team doing the validation is competent, a lot of the risk of incomplete requirements can be mitigated, at least in theory. However, the engineering of complex, never-been-done-before systems always has associated 'escape' risks. A lot will depend on how the development effort is phased, and whether or not sufficient system engineering is performed up front, with sufficient lead time to modify/add to the design without severely negatively affecting the overall development in terms of cost or schedule.

In the end, of course, dealing with a competent and ethical development group is key. In my opinion, the contracts folks shouldn't "get in the way" of doing the right thing if problems surface. But in today's world, with today's financial sensitivities--and today's ethics--there are risks.

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:

[Anonymous Coward]

I think the GP was probably referring to the scarcity of water on Mars rather than its hardness, but could be wrong...

Re:Impact

[Dakkus]

Dude! There's nothing but water in Mars. It's just red. Just like in Red Sea.

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?

[TimmyDee]

"The Hypercone is bigger and costs more."

--Vorticity Ltd.

Re:

[WindBourne]

IANAE, but I think that the issue is pretty obvious. I am guessing that they want the craft to take a direct landing rather than burning up some speed in the outer atmosphere. With a parachute as soon as you open it, it takes ALL of the stress up front. IOW, you just hit your brakes in full. It is possible (and in fact probable) that you will rip the chute. With the hypercone, it will be folded up on itself. You will get less drag on the "chute", but sufficient to start a slow "slowing". As the speeds, the

Re:

[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.

Re:Parachute?

[DeeVeeAnt]

Actually the difference is that a parachute would instantly shred at the supersonic speeds they are talking about. It needs a clever shape and tougher materials. They will probably need to make it out of unobtainium.

Re:

[timmarhy]

so it's just a fancy parachute?

Re:

[UncleTogie]

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

When I first saw the "hypercone" I just figured they played a lot of badminton. Squash a shuttlecock, show it to marketing, and Presto, you have a "hypercone"...

Re:Parachute?

[ArsonSmith]

I didn't read the article or anything but from what I gather this will work while a parachute wont.

Re:Parachute?

[Rosco P. Coltrane]

Some care to elaborate on the difference between hitting the ground at mach 4 and hitting the ground at mach 1?

Hitting the ground mach 3 slower.

Re:

[chris_mahan]

So I guess this adds one more possibility to the list of explanations behind the unfathomable black holes on Mars.

Space ladder?

[theurge14]

Just extend the space ladder from Earth to Mars.

Re:

[Spy der Mann]

Just make sure it doesn't wrap around the sun, or we're fried.

Re:Space ladder?

[BlueParrot]

A space elevator would actually not be such a bad idea. You can deploy it from orbit, and since Mars has a lower mass than earth it would significantly reduce the requirements of the cable. Getting the damned thing there might be a bit difficult thou.

Re:

[compro01]

Not to mention that it might have to be pretty stretchy since earth and mars don't have synchronous orbits

then all we need to do is devise a way of making them synchronous!

Re:

[theurge14]

And Teflon nanotubes to survive being in the sun!

Hypercone looks like...

[Change]

Dunno about the rest of you, but the Hypercone immediately reminded me of a rolled-up condom.

I wonder when that idea...uh...arose?

Condom?

[Anonymous Coward]

Care to explain what a condom is to the rest of us /. geeks?

Space Elevator?

[bhmit1]

Would a space elevator be more feasible on Mars with the reduced gravity and atmosphere? Admittedly, you have to find a way to get a counterweight and cable all the way there, but it may be worth the tradeoff of the high speed landing with airbags, parachutes, rockets, and everything else we lug there to make it a slow crash. And surely rockets would be more useful than they say, otherwise, there's no way to get back off the planet.

Re:

[bhmit1]

There's also something to be said for splitting up the payload. Food and equipment can be sent ahead of time and land much faster than people need to. All the people need is a lightweight lander and some way to travel to the other equipment. Why are they determined to send it in one large complicated package?

Re:

[BlueParrot]

Would a space elevator be more feasible on Mars with the reduced gravity and atmosphere? Yes, unfortunately Mars also has two moons with orbits that intersect the equatorial plane. Thus this means you would either have to keep the space elevator mobile ( maybe along some track on the surface ) or you would have to shift the orbit of a 22km diameter rock. Taking care of the moon the old fashion American way unfortunately won't work as the amount of scrap that would be flying around in the orbit would becom

Re:Space Elevator?

[Kozar_The_Malignant]

Meh! Build the elevator and counterweights out of the moons.

Re:

[smbarbour]

The counterweight doesn't necessarily need to be a problem. A robotic ship with ion engines could probably retrieve an asteroid from the "nearby" belt to use as a counterweight. The logical course of action to reliably placing humans on Mars, would be to start with a lunar base on Deimos or Phobos (maybe both to ensure that control could be maintained while one or the other is out of radio contact, although satellites could work for that purpose as well). From there you can have robots construct a space

Re:Space Elevator?

[bigbigbison]

Bases on Deimos and Phobos? Surely such an effort would be Doomed.

Re:

[fjf33]

It has been mentioned before in both SF and Scientific Literature. It is easier because you have Olympus Mons which takes you WAAAAY up so that you avoid most/all of the little atmosphere that is there. The gravity is obviously less which helps a lot. The problem of the moon getting close to the tether was avoided by sending elevators up and down at calculated intervals to set up a resonance motion therefore making the cable undulate like a string, therefore avoiding the moon altogether.

Armadillo

[WindBourne]

Look, if it is possible to take a craft like the armadillo to Earth's LEO and back, then it will be easy enough to do the same at Mars. And yes, it is in a moon style approach. Of course, it might be better to have a better fail safe approach to it, such as the hypercone.

Mach 3 Chute

[Nyeerrmm]

I did a project on this about a year and a half ago, and the solution we came to was in fact a parachute, but one capable of opening at Mach 2 or 3, similar to what Viking used. Unfortunately, since this has little use on Earth it is a very costly development process, and anything larger than Viking is significantly different, and a higher velocity opening speed would be nice. Following this a normal parachute, retro rockets, airbags or combinations thereof are still necessary.

Also, the problem with a retro rocket the whole way isnt just that its heavier gravity (just means more fuel,) but also the process of igniting a rocket with an incident airflow of mach 3 or higher is not a trivial problem.

Overall, Mars is the hardest place to land in the inner solar system. the Moon and Mercury are small and have no atmosphere, so Apollo is an obvious and easy choice. Venus has an atmosphere so thick you can drop any funny shaped item in and it will drop to the surface at low speeds, assuming the static heat doesnt destroy it. Earth, obviously, you can do well enough if you're careful with the shape and throw up some parachutes at the end. Mars though has such a thin atmosphere it makes everthing hard.

This concept sure looks interesting though.

Re:

[secPM_MS]

I suspect that the lines in the parachute would be vaporized upon entry. The cone provides a heat-shield type environment that is reasonably stable until the velocity drops to a reasonable level.

Personally, I think this is a waste of money and time. Use probes. Why do we want to drop down a gravity well anyway? If we are going into space, go for the smaller bodies (asteroids / pseudo-comets, etc). The energetics for the earth crossing asteroids are definitely favorable and they have available mass that ca

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:

[MikeFM]

Why not split off the humans from their supplies and land in two stages? Land the supplies using some mix of the before-mentioned possibilities (rockets, chutes, and airbags) and the humans on their own. The article made it sound as if small craft might land with chutes without to hard a landing. As for the supplies - well as long as they survive the landing they don't have to be let down near as carefully as the people.

I just find it hard to believe that among all the so called intelligent beings from Eart

Re:

[einhverfr]

I had two solutions after reading the article. Both of which require rethinking the design of the CEV a bit.

The real challenge is that no matter what you do, you are moving *fast* at the beginning of the entry to the Martian atmosphere.

1) Very Large Heat Shields. The primary challenge to this is that it is next to impossible to launch them from earth. So don't launch them from earth-- assemble in earth orbit instead. This would require switching to more established systems after reaching mach 1.

2) Ver

Oh Yeah? Try Landing on Jupiter!

[iamlucky13]

You're going to have a lot harder time landing on a body with no surface (or at least it's so deep we don't know where it becomes solid).

I'm a little bothered that the article dismisses as useless components that in actuality will probably be used for landing on Mars and are unrelated to the problem addressed in the article, and it tends to treat each idea as a complete solution, rather than pieces of a multistate solution.

The problem is not touching down on the surface. It's that first bit of decelleration during which you cover most of the distance to the ground. You've got to bleed off a lot of speed really fast, and Mars atmosphere isn't very conducive to accomplishing that. The article does cover this part well.

Previous landers, especially the Mars Exploration Rovers, have used multiple stages. The first is the heat shield. Because of their small size, the MER's have a high surface area/mass ratio. The heat shield slowed them down to mach 2 and a supersonic parachute deploys. Then retrorockets fired, slowing it to a complete stop a little ways above the ground, and lastly, the cable cut, dropping it relatively gingerly onto the airbags.

So just for the little MER's, there were actually 4 stages involved: heat shield, parachute, retro-rockets, and airbags. Although the article on focus on the airbags in its discussion of the MER, those were really only to allow a margin of error for the retrorockets (although a needed one), and were unrelated to the supersonic transition part.

The hypercone is basically a specially-shaped parachute, but it still won't slow a lander sufficiently to survive hitting the ground. I'm expecting the final solution if we ever commit to it will include heat shield, hypersonic chute, possible a middle stage chute, main chute, retrorockets, and airbags.

Also, you mention lighting a rocket in a supersonic airstream is hard (I'm not sure about that...the combustion chamber is static), and the article claims it would be better if Mars had no atmosphere. Regardless, if you're committing to rockets for anything more than what a modestly sized parachute leaves you travelling, then it doesn't much matter if you use the rockets down near the ground, or as part of a longer de-orbit burn. Either way you're getting rid of KE.

Re:

[khallow]

Overall, Mars is the hardest place to land in the inner solar system.

Hard I suppose is relative, but as I understand it Mercury, Venus, and the Moon all require more delta V to get there once you take into account the advantages of atmospheric braking. More delta V means "harder" for me.

Also, the problem with a retro rocket the whole way isnt just that its heavier gravity (just means more fuel,) but also the process of igniting a rocket with an incident airflow of mach 3 or higher is not a trivial pr

Re:Mach 3 Chute

[king-manic]

Overall, Mars is the hardest place to land in the inner solar system

I think the sun presents a greater issue.

One lander per person?

[rleibman]

If the problem is that you can't land the whole crew at once because of weight... why don't you land each member separately, in tiny containers and then a big load with the unmanned portion of the mission? Another advantage of something like this is that if one of the landings fails and you lose a team member your mission is still safe.

Mmmmm... RAIA

[Anonymous Coward]

Redundant Array of Inexpensive Astronauts

Re:

[rleibman]

Funny, not Starship troopers, in fact I just now thought of that, but it may have been on the back of my mind as I'm rereading my favorite Heinleins to celebrate his 100th anniversary.

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

[khallow]

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 don't do a better job of colonizing other planets. Terraforming Mars is only a step in its colonization. The first and most important step is having people live on Mars. Second, there are all sorts of unpleasant things that can happen to people on Earth. In addition to the small chances of extinction, I think there's a good chance that we reset civilization in the next century or two. Aggressive space colonization can get us a foothold in space before nuclear war, a biological weapon, or other human-made disaster can set back Earth-side civilization to the early industrial age or earlier. Alternately, we could face centuries or millenia of stagnation in a "water empire" [wikipedia.org] style government. In other words, colonizing space, particular the Moon, Mars, and other select bodies is a great way to diversify the habitat of human life.

We could wait for the next big technology advance like nanotech, or we could get started with the capabilities we currently have rather than count on the uncertain future to do our work for us.

Another point is that we can expand our economy into space. Sure you can expand it profitably into deep ocean, Antartica, etc. No reason not too unless you're an environmental type in which case you should like the absence of an environment to harm in space. But space has the benefit that there's a lot more of it with a lot of energy and mass available, dwarfing anything available on Earth. Economic expansion past a certain point will require a presence in space.

Re:

[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

Re:

[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 w

Message for Humanity

[sehlat]

all these worlds are yours
except mars
attempt no landing there

Re:Message for Humanity

[Rosco P. Coltrane]

Dude, this is Slashdot. The proper message is:

All your base are belong to us
You are on the way to destruction
What you say!

How about a "Sky Crane"

[Avionics Guy]

This is how JPL intends to land the next rover, Mars Science Laboratory: http://video.google.com/videoplay?docid=1404791803 599052711 [google.com].

Robots should build a landing strip first

[six11]

Perhaps I am inclined to think things like this because everybody around me has an infection for which the only antidote is "robots", but... Robots!

We should send a massive fleet of robots down and they can build a runway of some sort. Once they've finished that, they can also build a little village complete with a bar. That way when people go to mars, they have a place to land, and then they can get a drink and maybe some munchies.

Distributed, Forward Stage Lander

[aldheorte]

All these ideas seem to assume a heavy lander is necessary. Pack 4 of everything since you want backups anyway. Break up all the parts of the habitation module and such into separate small pieces that break up from each other just when the atmosphere is encountered so they land in roughly the same area using already proven landing mechanisms. Assemble them with the humans still in orbit using proven rovers, robotics, and UAV technology (and with local humans, minimal time delay). Make sure environmental con

Airbags can't be used...

[posterlogo]

...for OBVIOUS reasons? This is not so obvious to me. It will obviously feel kind of funky, but some of the amusement park rides out there are pretty brutal already. Now, I know you can't just drop them like pathfinder, but the last two rovers were quite big and complex, and NASA didn't exactly want them bouncing around all over Mars -- I'm not at all convinced humans couldn't survive that, especially in combination with a partially powered descent and parachutes. At the least we should be able to model thi

Re:

[MoodyLoner]

It will obviously feel kind of funky, but some of the amusement park rides out there are pretty brutal already.

Twenty gees.
What amusement parks do you go to?

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).

One word.

[Fantom42]

Nuclear.

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:

[VENONA]

Read Zubrin's _The Case for Mars_, which goes into quite a lot of detail. It covers cancer risks, etc. It *doesn't* cover the landing issue, beyond assuming aerobraking.

The basic scheme is to send an atmosphere converter ahead of the manned mission to create a stock of methane and oxygen propellants for the return, as most of the mass you'll need is still fuel. Mars has a surface gravity around 1/3 of Earth's, so quantities required are much lower than for the trip out. In a way, you're right about using nu

Airbags?

[PhotoGuy]

Why can't air bags be used? If the balloon bags that the last probes bounced around and landed with, were okay for all the sensitive equipment aboard, would they not be okay for humans? Or did those landers still take one hell of a beating, and were just tough enough to stand it? Anyone know the impact forces the gear sustained?

How does K'breel do it?

[bl8n8r]

I'm sure they laugh at our measly doughnuts.

Unit conversion

[jimmux]

I suspect mach 1 on Mars is not the same as mach 1 on Earth (due to different speeds of sound in the planet's respective atmospheres). Which are they actually refering to in this case?

The true terror begins

[monopole]

As the astronauts consider if the calculations were made in metric or imperial units.

Stop wasting time on Mars

[stmfreak]

We should focus on establishing a presence in space first. Let's get space working for lots of people, not just a select three at a time (plus celebrity). Think asteroid mining. Collecting hydrogen from the solar wind. Solar power arrays beaming clean energy back to Earth. Once we have refueling and industrial capacity in orbit or on platforms around the solar system, conquering the gravity wells of the other planets will merely be costly.

Six minutes of terror

[slickwillie]

I thought it was going to be a story about my sex life.

Re:Six minutes of terror

[slickwillie]

Who said there was anyone else involved?

What about Venus?

[Door-opening Fascist]

I've always thought that floating cities on Venus [wikipedia.org] would be pretty cool. You wouldn't need to break that much, because at 50km up the atmosphere is already as dense as it is on Earth at sea level.

Re:

[Frosty Piss]

It's a gas bag, as is an air bag. But it's not filled with air...

Re:Make up your mind

[tulmad]

The current landing setup (the one used on the rovers) involves inflating airbags around the lander, then bouncing the lander into the surface at high speeds, then eventually coming to a stop after a few bounces. This is fine when your lander is filled with robotics, but would obviously be bad when the lander is filled with people.

The landing setup they're proposing is actually more like an air-braking system. It inflates around the lander while it's still at a high enough altitude, giving the lander a considerably larger volume. This would hopefully slow the lander as it continues its descent.

Re:

[halcyon1234]

Then why not drop a robot bulldozer onto Mars via airbags. Once it lands, have it build a huge, flat landing strip. Then just land on Mars. Just fly around the planet a few times to shed off a few machs using air brakes or retro-rockets or whatever. Then glide in, land, and voila! You're on Mars.

Re:

[belmolis]

You're assuming that things are like they are on earth. Air brakes won't work because the atmosphere is too thin. Retrorockets require a lot of fuel.

Re:Make up your mind

[halcyon1234]

Even if the atmosphere isn't as thick, it's still an atmosphere. Mach 4 is 1361.1 m/s. The escape velocity of Mars is 5.027 km/s. If you enter at Mach 4, you have nowhere to go but down. Deploy a large enough glider, and you will glide. Since the atmosphere isn't a vacuum, there will be drag. Fly around long enough, and you will slow down enough to glide safely in. I'd rather spend a few hours circling the runway than six seconds ramming into it.

Re:

[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:

[X0563511]

You know, that would work but for the trick with slowing down once touched-down. Here, we use some parachutes to slow the shuttle down, and that is a HUUUGE runway... and that runway was a single concrete pour that lasted several years. And the air here is much denser, making those parachutes much more efficient than they would be on Mars.

The logistics alone in making that runway are impossible without getting people there first... and then what about the materials?

Re:

[jnnnnn]

The flight simulator X-Plane has dynamics for Mars (or did have, years ago), and there were a few planes that would fly in a Mars atmosphere. They had to fly quite fast and had fairly (but not obscenely) large wings.

I don't think the Shuttle would cut it, however.

There's a big difference.

[MrTrick]

The 'airbag' approach means BOUNCING.

Humans don't bounce too well, and neither does anything with too much mass (inertia). It was okay for the landers because they are much smaller than a manned spacecraft was.
(analogous to the oft-quoted maxim that you can drop a mouse from any height and it will survive, but a cat will not)

As the craft gets heavier, the size of the airbags that would be required to safely land it would I think increase geometrically.

Even with huge ...'tracts of land'... it will probably n

Re:

[networkBoy]

Um...
not entirely true. Drop a mouse from high enough and it will burn up.

(yes I know what you meant, but still...)
-nB

Re:

[fred fleenblat]

Jet engines require oxygen, of which there is very little in the Martian atmosphere.

Re:

[physicsnick]

Theoretically, sure, but in practice, no.

Fuel. It takes way too much fuel to stop your orbital motion and to avoid crashing into the planet at a million miles per hour. That's why shuttles on Earth are designed like planes; they counteract gravity using air resistance, the same way planes do.

Having to bring fuel along means the costs go up exponentially. Putting enough fuel in space for both a landing and a launch from Mars would cost simply too much, especially when a little research could yield us some al

Re:

[wile_e_wonka]

I think the reason they don't do this is because NASA has had a hard time finding reliable martians with which it could entrust the construction of the landing strip [wikimedia.org].

Re:Same way they land on Earth

[BlueParrot]

The main problem with landing is that you pick up quite a bit of speed from falling towards the planet. On Earth we take advantage of the air resistance in a relatively thick atmosphere to slow down the space shuttle as it returns. Mars has a MUCH thinner atmosphere so for large objects this won't work. You either end up going in at such a flat angle that you just bounce straight off the atmsophere like a skipping stone, or you go in too steep so that you are unable to lose enough speed before hitting the surface. It is possible to land on objects with no atmosphere ( like the moon ) using retro-rockets to slow down your descent, but because mars has a much stronger gravity this becomes impractical.

Re:Same way they land on Earth

[Bin Naden]

What about a huge blimp? You carry frozen helium all the way to mars, then heat it before entry to fill a huge blimp.

Re:

[Rocketship Underpant]

Now, that's an interesting idea -- a lighter-than-air lander. But is it even possible in an atmosphere as thin as Mars?

Re:Same way they land on Earth

[Cecil]

The thermal heat capacity of space is also near 0. It's only "cold" in space because it's incapable of holding heat. If you put something in space, the only kind of cooling it can do is radiative. This is not nearly enough to counter the heating effect of solar radiation it absorbs.

Re:

[evilviper]

If you put something in space, the only kind of cooling it can do is radiative. This is not nearly enough to counter the heating effect of solar radiation it absorbs.

Actually it is. You can get either effect you want.

On the side facing the sun, you have the most reflective colors possible, either reflective (polished metal) or white. On the side that is in the shadow of your own craft, you use the darkest shade of black you can find.

The Space Shuttle already does something similar. The cargo doors are bl

Re:

[terrymr]

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

Re:

[soft_guy]

Obviously we need to go to Mars to fight Al Qaeda. Duh. It is part of the "war on financial sanity" that Bush is waging.

Re:

[Lee148]

Dude, read the article.

Re:

[reverseengineer]

That's the first thing that came to my mind when I read the summary. I think the notion is that airbags couldn't be deployed in the same sort of system used for the last few Mars rover projects, with a stately tetrahedron of cushions surrounding the rover package. If you've seen any of the NASA CGI dramatizations of what happens in these rover landings, these packages seem to hit pretty hard, and bounce wildly in all directions and orientations before settling to a stop.

I'm guessing the notion here is t

Re:

[ookabooka]

What are those "obvious" reasons? Air bags were used for the two bugs that are up there right now.

Because those things experienced a crap ton of G's when they hit. . erm, bounced off the ground, not to mention the rotational forces as the thing spins around before coming to a rest. Electronics and metal handle G's a bit better than us humans.

Re:

[sholden]

Those "bugs" aren't people and hence don't have internal organs that go splat.

Re:

[crabpeople]

It would splinter your spine. I bet you have never been in a high speed collision...

Re:

[wile_e_wonka]

Couldn't they make a sort of spherical container with an exterior shell and an interior shell. The exterior shell would be a completely separate piece from the interior shell and would hold the airbag equipment. The interior shell would be made to move freely inside the exterior shell, kept in proper position with gyroscopic technology. Put some shock absorbers on the astronaut's seats, and then you're set.

This is very rudimentary of course, but it seems plausible with my minuscule knowledge of physics a

Re:

[Abcd1234]

Because all that does is deal with roll issues. You still have the sudden, massive decceleration as the airbag hits the ground, creating intense G forces that a rover might be able to withstand, while a human would be turned into a lovely meat paste.

Re:

[compro01]

a box of circuits wouldn't mind 20 or go Gees on impact, but a human would have some issues with it.

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.