Author Topic: Inflatable re-entry vehicle?  (Read 45653 times)

Offline JasonAW3

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Inflatable re-entry vehicle?
« on: 03/02/2010 04:26 am »
Another weird thought for everyone;

     As inflatable prop driven planes have not only been built, but flown, (Goodyear did it in the late fourties or early fifties) and Bigalow Aerospace is building inflatable habitat modules, if one could use a ceramic thermal blanket, much like the ones on the upper surface of the Space Shuttlle's wing, surrounding a inflatable lifting body shaped structurte and use it as a re-entry vehicle?
     Would it require some sort of internal structure for rigidity, or would it work better being flexible?  Would a capsule or lifting body work better?
     We've already experimented with an inflatible aerobrake, and it appears that it could work for aerocapture, but could it work to actually return a crew or cargo planetside?

     As an added benifit, should a water landing be required, it's already inflated, so it sould float just fine!

     Just FYI, I call this kind of weird thinking, thinking outside of the can.

« Last Edit: 03/02/2010 05:35 am by JasonAW3 »
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Offline meiza

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Re: Inflatable re-entry vehicle?
« Reply #1 on: 03/02/2010 09:51 am »
They're called ballutes and have been investigated.
http://www.andrews-space.com/content-main.php?subsection=MTA0

IIRC, some Russian ballutes have flown but I don't remember if any have been recovered.

Offline Paul Adams

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Re: Inflatable re-entry vehicle?
« Reply #2 on: 03/02/2010 10:27 am »
I am working with a group looking at inflateable re-entry vehicles as a technological spin-off of another project.

It is quite feasible and promises a low cost means of returning cargo from orbit.

The main question now is how much cargo is there to return from orbit?

Paul
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Offline A_M_Swallow

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Re: Inflatable re-entry vehicle?
« Reply #3 on: 03/02/2010 04:51 pm »
Until we mine the Moon and asteroids only small amounts of cargo need returning to the Earth.

There may be a market for returning to the Earth the upper stages of launch vehicles going to low Earth orbit (LEO).  Currently it is cheaper to buy new upper stages and crash the used ones back than fit heat shields, including the cost of reduced payload.

Spaceships repeatedly flying between LEO and say the Earth-Moon Lagrange points could use a low cost way of slowing down on the return journey.  Lifting the propellant to perform the 3.77 km/s delta-v is normally considered too expensive, so currently spacecraft reenter.
http://en.wikipedia.org/wiki/Aerocapture

Offline neilh

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Re: Inflatable re-entry vehicle?
« Reply #4 on: 03/02/2010 05:07 pm »
Some other random ideas along these lines: Perhaps the heat from reentry could be used to heat up the internal gas of the inflatable, so it could essentially act as a hot-air balloon on the way down. After velocity is lost, it could help reduce the rate of descent or even float above-ground.

If there's a sufficient amount of internal gas, perhaps it could even act as a buffer for reentry heat. I imagine you'd have to come up with some sort of protect passengers/cargo from the heat, though.
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Offline Robotbeat

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Re: Inflatable re-entry vehicle?
« Reply #5 on: 03/02/2010 05:23 pm »
Orbital manufacturing techniques which require ultrahigh vacuum or microgravity require that the products be returned to Earth. One example is large pieces of metal foam, far larger than can be produced on Earth with a consistent foam structure. Industrial high-purity drug production would be another example. Another is hollow ball bearings. There are lots of biomedical applications, as well. High quality artificial gems may be another possibility. All of these examples would need large-scale down-mass if they really took off.

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Offline Paul Adams

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Re: Inflatable re-entry vehicle?
« Reply #6 on: 03/02/2010 06:11 pm »

That is an interesting thought. The re-entry stuctures we are considering could be made very large without much weight and so could bring a first stage down quite gentally.

We have already done a drop test to look at stability, and the thermal requirements we understand and can handle.


Until we mine the Moon and asteroids only small amounts of cargo need returning to the Earth.

There may be a market for returning to the Earth the upper stages of launch vehicles going to low Earth orbit (LEO).  Currently it is cheaper to buy new upper stages and crash the used ones back than fit heat shields, including the cost of reduced payload.

Spaceships repeatedly flying between LEO and say the Earth-Moon Lagrange points could use a low cost way of slowing down on the return journey.  Lifting the propellant to perform the 3.77 km/s delta-v is normally considered too expensive, so currently spacecraft reenter.
http://en.wikipedia.org/wiki/Aerocapture
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Offline daniela

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Re: Inflatable re-entry vehicle?
« Reply #7 on: 03/02/2010 06:17 pm »
Google IRDT. Was considered by Russians and Esa. Some have flown.

Offline JasonAW3

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Re: Inflatable re-entry vehicle?
« Reply #8 on: 03/03/2010 01:50 am »
Ok,

     I guess I wasn't clear enough.

     What I am proposing is using a TPS shielded inflatable habitat module AS a rentry vehicle, not to use a ballute as the TPS system.  In other words, put a returning crew, samples, etc. into an inflatable structure, covered in a TPS blanket, with only enough of a rigid structure to hold the basic shape intact during re-entry, and to handle the Gee loads from either parachute deployment and landing, or if it's an inflatable lifting body, from the skidding across either a desert surface or water for ocean landings.

     A capsule shaped re-entry inflatable would use a combination of inflatable / deflatable flaps and cold gas jets for re-entry maneuvers as would an inflatable lifting body.

     An inflatable capsule could land on land or water, with the addition of a n inflatable pad between the inner hab module and the TPS blanket, with some blow-out panels.

I do'n't kbow how practicle this would be, but it is an interesting idea.

Jason
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Offline KelvinZero

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Re: Inflatable re-entry vehicle?
« Reply #9 on: 03/03/2010 07:18 am »

The main question now is how much cargo is there to return from orbit?

Paul

My uninformed opinion: Not just how much, but how often and what size when you do.

I am guessing that usually we dont need to return much intact (apart from crew) but sometimes we want to return a fairly large object. For example even if you are not reusing an upper stage it must be useful to be able to examine one in detail after real use occasionally.

This idea of an inflatable re-entry vehicle seems very worthwhile because it could let you occasionally return large objects when really needed while not paying for this ability even in missions where it is not required, as with the shuttle.

Offline JasonAW3

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Re: Inflatable re-entry vehicle?
« Reply #10 on: 03/04/2010 12:57 am »

The main question now is how much cargo is there to return from orbit?

Paul

My uninformed opinion: Not just how much, but how often and what size when you do.

I am guessing that usually we dont need to return much intact (apart from crew) but sometimes we want to return a fairly large object. For example even if you are not reusing an upper stage it must be useful to be able to examine one in detail after real use occasionally.

This idea of an inflatable re-entry vehicle seems very worthwhile because it could let you occasionally return large objects when really needed while not paying for this ability even in missions where it is not required, as with the shuttle.

     The biggest issue that I can see would be recovery of cargos. 

     Parachutes would be effective in slowing down the particular cargo, but in the case of a large, heavy, delicate cargo, (like the Hubble Telescope) you would probably want to use an inflatable lifting body drone full of helium and set up a crushable, expanded foam layer between the TPS and the inner pressure layer, then, for the final several hundred feet, you'd want both a series of rocket deployed parachutes and a retro pack, like the Russians use (or used to use) on the Soyuz capsules for their landing.

     Arial capture of really large cargos, (like Hubble) would be impractical, and most likely too dangerous for any sort of airplane capture, like via a C-130, C-17 or a C-5A.  Dangling at the end of a teather or it's parachutes would make most cargos uncontrollable.  (Unless the inflatable is a lifting body, in which case. if the teather is on the front of the inflatible, then it could be flown into the cargo bay of one of these craft, by remot control, as its' teather is taken up on a spool).

     However, on the subject of crew retrieval, it occured to me that if the inflatables were too flexible, a lightweight outer structure (maybe plywood and fiberglass?) with a disposable TPS applied to the outer shell (probably the same sort of TPS that Orion would have used.  By using an inflatable for the pressure hull and putting the RCS thrusters and other equipment that needs to be kept external to the pressure hull attached to the ultra-light weight hull, would create a craft that would mass a fraction of an all metal, or partially composit types of craft.

     Could anyone double check this for me?  Essentially, I am suggesting using the fiberglass and wood "mock-up" with working control surfaces, hybrid rocket motors, and the actual TPS coating for the Orion craft, AS The Actual Space Craft!  Is this nuts or could it actually work?  If so, the actual mass and costruction cost of such a beast would be in the thousands of dollars, with the exceptions of the RCS systems, Avionics, Hybrid motors, which would be modular and easily removable from the semi-disposable shell. (Would the resins used for the fiberglass covering of the wood handle vacume and extremes of heat and cold?  Maybe a mylar insulating layer could be used as well?

Jason
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Offline RanulfC

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Re: Inflatable re-entry vehicle?
« Reply #11 on: 03/04/2010 04:08 pm »
FYI: The Goodyear "InflatoPlane" structural concept was explored by Goodyear for several other possible uses including commercial aircraft, light-aircraft flyers market AND a concept for a Reentry vehicle. Unfortunatly not a lot of documentation for ANY of the concepts let alone the construction and manufacturing for the Inflatiplane have been found.

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Offline JasonAW3

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Re: Inflatable re-entry vehicle?
« Reply #12 on: 03/04/2010 04:31 pm »
FYI: The Goodyear "InflatoPlane" structural concept was explored by Goodyear for several other possible uses including commercial aircraft, light-aircraft flyers market AND a concept for a Reentry vehicle. Unfortunatly not a lot of documentation for ANY of the concepts let alone the construction and manufacturing for the Inflatiplane have been found.

Randy

Hmmmm...

     Got to admit, I didn't know that they'd explored the use of the Inflatoplane for a re-entry vehicle!  Wow!

     After thinking about it, I am uncertain whether or not an inflated structure, even with a good flexible TPS system, could handle the transition to supersonic speeds, let alone hypersonic speeds.  That's why I was looking at the disposable outer shell concept.  Properly designed with drop and lock skids or wheeled single use hydraulic landing gears, (and a drogue parachute to slow it to a stop) it should be able to act as a pretty good lifting body.

Jason
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Offline colbourne

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Re: Inflatable re-entry vehicle?
« Reply #13 on: 03/06/2010 03:18 am »
I thought as an inflatable or telescopic wing might make sense for landing on Mars.

Landing heavy vehicles on Mars is difficult to do without massive rockets so any lightweight solution would be great.

If we can slow down in the atmosphere and then convert the speed into lift we can then use maybe rockets for the last few feet. Parachutes have the problem that you hit the planet fast before getting to a sensible speed.

Offline Jim

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Re: Inflatable re-entry vehicle?
« Reply #14 on: 03/06/2010 11:25 am »
I thought as an inflatable or telescopic wing might make sense for landing on Mars.

Landing heavy vehicles on Mars is difficult to do without massive rockets so any lightweight solution would be great.

If we can slow down in the atmosphere and then convert the speed into lift we can then use maybe rockets for the last few feet. Parachutes have the problem that you hit the planet fast before getting to a sensible speed.

No, you just don't get it.  The atmosphere is too thin.  Like we have said to you many times, rockets are needed for more than a few feet.  The wings would be enormous  and instead of a vertical speed then is now a high horizontal speed.


Offline JasonAW3

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Re: Inflatable re-entry vehicle?
« Reply #15 on: 03/06/2010 01:36 pm »
I thought as an inflatable or telescopic wing might make sense for landing on Mars.

Landing heavy vehicles on Mars is difficult to do without massive rockets so any lightweight solution would be great.

If we can slow down in the atmosphere and then convert the speed into lift we can then use maybe rockets for the last few feet. Parachutes have the problem that you hit the planet fast before getting to a sensible speed.

No, you just don't get it.  The atmosphere is too thin.  Like we have said to you many times, rockets are needed for more than a few feet.  The wings would be enormous  and instead of a vertical speed then is now a high horizontal speed.



Ok Jim,

     Slow down please.   A few years back, NASA had proposed a drone type flyer to be deployed in much the same manner as described for a Mars Flyer.  The Flyer was to enter the Martian Atmosphere in ann aeroshell, slow to a certain speed several thousand feet above ground, pop the bottom loose and drop the drone, whose wings would unfold and take flight.  I seem to remember that they were debating whether to use a monopropellant for an internal combustion engine, or an RTG to power an electric motor to run the propeller.  They had experimenmted with both mechanically unfolding wings and inflatables in the stratosphere as a Mars analogue and had quite a bit of success when the project got canceled.  I think some of the technology and info got transfered to the Heilos project after that, or was it the other way around?  (Sorry, my memory's a bit fuzzy on this part).
     And as I seem to remember Titan was NOT the first place NASA proposed to send a hot air ballon, but Mars was.

     You can look up both projects on NASA's website.

     Now I realize that the Cube Root law would have a MAJOR effect here, possibly invalidating this idea, but to come in like gang busters and say that "you just don't get it" seems to me to be a bit rude.
     Maybe a craft like that would require a wingspan of five hundred plus feet with ten propellers twenty feet across with an average rotation of 10 rpm to remain aloft. I don't know.  I would have to run the numbers myself, but it seemks to me, with a central Bigalow style inflatable habitat, and a thin film  set of wings that could be hot air augmented, and an expanding foam reinforced wing spar, it could possibly work, but you'd have to land the module first, inflate it, expand the foam in the wingspars, and otherwise assemble the bird, then heat the martian air in the wings and tail sections, and you should atleast acheave neutral bouyancy. Then, a slight kick off the ground, run up the propellers to speed, and you're aloft! (Come to think of it, some of those prop driving motors, (most likely electric) could, in theory, be tilt rotors to take off kind of like the V-22 Osprey.  Using thin fild solar panels on top of the wing would augment the electrical power for the motors, as well as augment the heating of the martian air in the wings.

     I mean, if it weren't possible, why would NASA bother with parachutes for their Mars probes?  And why did VonBraun want to land a Flying Wing manned craft on Mars in the first place?  Prior to settling on the Giant Apollo Capsule design for some of the early baseline missions, NASA was actively considering a Lifting Body design for the Martain Landing.  In fact, some of the later Cargo Lander designs proposed by people like Boeing and Lockheed Marten, were suggesting use of lifting bodys, along with parachutes and rockets "For the last few hundred feet".  Now, maybe these systems wouldn't have worked for some reason that I don't know or comprehend, but the "Big Boys" thought they would.


Jason
« Last Edit: 03/06/2010 01:43 pm by JasonAW3 »
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Offline Jim

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Re: Inflatable re-entry vehicle?
« Reply #16 on: 03/06/2010 01:59 pm »

 1.      Now I realize that the Cube Root law would have a MAJOR effect here, possibly invalidating this idea, but to come in like gang busters and say that "you just don't get it" seems to me to be a bit rude.
   

 2.      I mean, if it weren't possible, why would NASA bother with parachutes for their Mars probes?  And why did VonBraun want to land a Flying Wing manned craft on Mars in the first place?  Prior to settling on the Giant Apollo Capsule design for some of the early baseline missions, NASA was actively considering a Lifting Body design for the Martain Landing.  In fact, some of the later Cargo Lander designs proposed by people like Boeing and Lockheed Marten, were suggesting use of lifting bodys, along with parachutes and rockets "For the last few hundred feet".  Now, maybe these systems wouldn't have worked for some reason that I don't know or comprehend, but the "Big Boys" thought they would.

We talking landing and not flying.

1.  this is a continuation of this thread
http://forum.nasaspaceflight.com/index.php?topic=17798.0

colbourne doesn't understand how thin the atmosphere is.

2.  Parachutes are used for deceleration and not landing.  Lifting bodies are for control during entry and not landing.

Offline JasonAW3

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Re: Inflatable re-entry vehicle?
« Reply #17 on: 03/06/2010 02:02 pm »
I thought as an inflatable or telescopic wing might make sense for landing on Mars.

Landing heavy vehicles on Mars is difficult to do without massive rockets so any lightweight solution would be great.

If we can slow down in the atmosphere and then convert the speed into lift we can then use maybe rockets for the last few feet. Parachutes have the problem that you hit the planet fast before getting to a sensible speed.

Nice idea, but I'm not a hundred percent sure it would work.

     Although NASA had experimented with similar ideas for a Mars Flyer as high up as the Stratosphere, and were largely successful, Jim has stated that this wouldn't work.  I'm thinking it's mostly a matter of scaling it up, as we run into the Cube Root law. Basicly, everytime you doulbe the size of an object, you triple it's mass.  I think that it may be that the size of the wing may become unmanageble.  Of course, if we're only talking about an inflatable lifting body to get cargos groundside, it MIGHT work, but there could be reliability issues, and I'm not certain that I'd trust an inflatable that has been stored in a vacume for nine months or more, to inflate without issue.  (In a vacume, materials tend to lose their flexibility, plastics start cracking, etc.)
     For something like that, for a manned lander, I'd want that system sealed away in a pressurized container until I was in orbit, then inflate it, give it both a systems diagnostic and a visual inspection including an EVA, in case patches are needed or the astronauts could spot something that might be missed on camera.  Either way, I wouldn't trust my life to it until I was one hundred percent certain that it wouldn't rupture on the way down.

     Jim, if you wouldn't mind, what issues are we overlooking on this subject?  I'd really like rto know so I don't keep coming up with stupid ideas that aren't well thought through.

Jason
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Offline JohnFornaro

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Re: Inflatable re-entry vehicle?
« Reply #18 on: 03/06/2010 02:12 pm »
I had never heard that VonBraun had considered a flying wing for Mars.  Is there a link for that?  I would have had to have been huge.

[How 'bout 'dat conjectural grammar?  "Would have had to have been"  What form is that?]
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Offline JasonAW3

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Re: Inflatable re-entry vehicle?
« Reply #19 on: 03/06/2010 02:25 pm »

 1.      Now I realize that the Cube Root law would have a MAJOR effect here, possibly invalidating this idea, but to come in like gang busters and say that "you just don't get it" seems to me to be a bit rude.
   

 2.      I mean, if it weren't possible, why would NASA bother with parachutes for their Mars probes?  And why did VonBraun want to land a Flying Wing manned craft on Mars in the first place?  Prior to settling on the Giant Apollo Capsule design for some of the early baseline missions, NASA was actively considering a Lifting Body design for the Martain Landing.  In fact, some of the later Cargo Lander designs proposed by people like Boeing and Lockheed Marten, were suggesting use of lifting bodys, along with parachutes and rockets "For the last few hundred feet".  Now, maybe these systems wouldn't have worked for some reason that I don't know or comprehend, but the "Big Boys" thought they would.

We talking landing and not flying.

1.  this is a continuation of this thread
http://forum.nasaspaceflight.com/index.php?topic=17798.0

colbourne doesn't understand how thin the atmosphere is.

2.  Parachutes are used for deceleration and not landing.  Lifting bodies are for control during entry and not landing.

Ok,

     I also skimmed through that first paper that was posted.
     I think that I see your point for the most part.  The lifting body inflatable would have to be HUGE, but not totally unmanageble, and would have to have a nearly flat bottom to disipate the heat and velocity.
     But here's an odd twist.  After doing both the entry deceleration with the lifting body, and the further atmospheric deceleration with a parachute, could a set of say three or more rapidly inflated balloons act to continue to decelerate the craft to a more managable speed?  I think it might conserve enough fuel to allow for an Apollo 11 type of landingsite change if need be.
     Mind you, the lifting body ballutes would be kept attached until the lander was at a relative descent velocity of 1 meter per second or less, gaining as much surface area lift and balloon lift from it as possible.

   Could this work?

Jason
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