A while ago we discussed the difficulties associated with aerobraking in the thin atmosphere of Mars. I seem to remember someone mentioning a concept where a Mars Lander used an extraordinarily wide, possibly inflatable, aerobrake in order to decelerate before landing. I even remember seeing an artists concept of the thing.

But now, for some reason, I can't find any references about this idea.

Here is an image I've made from memory; perhaps someone who knows what I am talking about can give me a reference, or perhaps tell why it wouldn't work.
http://www.orionsarm.com/ships/reentry2.png

Any ideas?

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Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

Ballute?

(My dim wit recalled "balut" which is something altogether different. Delicious, though.)

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That's probably it- interesting that the toroidal part is called a 'burble fence'- sounds like something out of Lewis Carroll.

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Here's a ballute which consists of nothing but a toroid-
http://fun3d.larc.nasa.gov/ballute_CAD.jpg
it seems that the torus is important for stability, so much so that you can get rid of the rest of the structure altogether.

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Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

Mar's areobraking works fine. What's the issue, again???

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I am Mugs, of the Alien clan of Usa, Nordamerica, a Terran, of Sol.

Perception isn't reality. It's merely an abstraction thereof, and quite often not a very good one at that.

I am human. Fully human.

I think the "issue" was inflatable devices for Mars aerobraking, the usage or proposals, and documentation thereof.

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Another version is this is the Hypercone.

Long and short of the issue is how much mass can be delivered to the surface under current designs for breaking?

They did that in the movie 2010

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Eagle Eye Observatory

Yes, it works fine for smaller, light weight craft.
But a simple cone shape, as used by Apollo landers, would not give enough surface area to brake a heavy craft in Mars' very thin atmosphere; so the cross sectional area of the aerobrake has to be increased, and a ballute is one way of doing this.

The toroidal section seems to be important in many designs- see this NASA proposal.
http://fun3d.larc.nasa.gov/ballute_CAD.jpg

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Higher lift entry designs, like ellipsleds and biconics are another way past the problem. They also have lower G and heat loadings as well, and can be targeted more accurately. NASA DRM versions 1.0, 2.0, 3.0, 4.0 and (what little I have seen) the forthcoming 5.0 all opt for this approach.

Jon

I didn't know what an ellipsled was, so I googled it; this pdf has examples of a number of ellipsled and biconic shapes
http://technology.arc.nasa.gov/docs/...tunePaper2.pdf
the ellipsled shape looks something like a lifting body without wings. Do you have any images of the current Martian proposals, Jon?

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I was aware of the neptune studies not had not seen one in such detail, Thanks! Ellipsleds are need transitional to lifting bodies, generating more lift than traditional shapes bu less than lifting bodies. Chapter 10 of Larson and Pranke's "Human spaceflight" (1999) has a useful discussion on these issues, but ufortunately does not go into various exotic solutions like ballutes, hypercones etc.

During the mid 80's to early 80's there was a lot of interest in bent biconics for both manned and unmanned landings. The shapes were based on classified work for manuoeverable missile wareheads. The is a nice series of artwork on such landers by Emmert Carter for the Case for Mars II and III conferences. Artwork yes, but the shapes are identical to what was considered. There portfolio is at http://spot.colorado.edu/~marscase/c...cfm84plan.html

The NASA Mars 3.0 DRM showed looking into modelling heat flow on a straight triconic shape in section A3.3.3 and A3.3.4 at http://ston.jsc.nasa.gov/collections...P-6107-ADD.pdf (4 MB file)

Hope this helps.

Cheers

Jon

Yes, it does: thanks for that.

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Orion's Arm . The Starlark . Voices: Future Tense . OA Flickr set

By the way, that's an excellent drawing. You should be an artist! (If you aren't already)

Your drawing appears as if it would work. There might be a few stiff arms from the hub to the rim, though.

__________________
I am Mugs, of the Alien clan of Usa, Nordamerica, a Terran, of Sol.

Perception isn't reality. It's merely an abstraction thereof, and quite often not a very good one at that.

I am human. Fully human.