Author Topic: What are advantages and disadvantages of powered and aerodynamic landing?  (Read 38855 times)

Offline Archer

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Thank you for your answers!

I was thinking about transportation between factory in LEO (space station in LEO) and Earth, not other planets (I cannot imagine why we will have a lot of traffic from other planets/Moon soon).

Actually, I was trying to find out what types goods can be manufactured in space, which would justify such venture.
Surprisingly, I couldn't find any information about how much would be price of kg of something transported from LEO to Earth.
It seems that nobody ever made even a paper-spacecraft, designed to bring goods from orbit to surface; spacecraft that is designed to be launched empty (and refueled in orbit if it uses powered landing), and return with cargo.

With current launch prices, I guess, only mining gold and platinum from asteroids will close the business case, but if the price can be less than 100$ per kg down, we have more options.


The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline Solman

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Thank you for your answers!

I was thinking about transportation between factory in LEO (space station in LEO) and Earth, not other planets (I cannot imagine why we will have a lot of traffic from other planets/Moon soon).

Actually, I was trying to find out what types goods can be manufactured in space, which would justify such venture.
Surprisingly, I couldn't find any information about how much would be price of kg of something transported from LEO to Earth.
It seems that nobody ever made even a paper-spacecraft, designed to bring goods from orbit to surface; spacecraft that is designed to be launched empty (and refueled in orbit if it uses powered landing), and return with cargo.

With current launch prices, I guess, only mining gold and platinum from asteroids will close the business case, but if the price can be less than 100$ per kg down, we have more options.




 I remember reading a book years ago by the British Interplanetary Society called "Man and the Planets" that mentioned using waveriders of such a simple design and low mass that they were disposable. They glided to a horizontal landing.

 The first thing to manufacture in space is perhaps spacecraft. After all - they are so valuable that it is worth the cost of launching them to orbit.

Steve

Offline gbaikie

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What are advantages and disadvantages of powered landing (future Dragon) and aerodynamic (Space Shuttle, Dream Chaser) landing types?

For example, let's assume I have a factory at LEO :), and I need to transport product from LEO to Earth, and also to move workers up and down (just a thought experiment).

As mentioned, it depends upon cost of rocket fuel in orbit. Or the cost of getting rocket fuel from earth. So with SpaceX and it's plan of lowering payload to $100 per lb- one essential has the cost of rocket fuel of whatever is left the rocket as less than $100 per lb [you don't need go somewhere to get it- because already available].

So if rocket fuel as cheap as $100 per lb, it favors using more rocket fuel to brake with.

As for thought experiment of a factory in space. I am guessing you mean something which doesn't high volume- making drugs or something with low mass but is valuable. So perhaps 10 tons per year shipped to earth per year? With increase possible, perhaps to say 100 tons per year?

And you want move worker up to space. And that seems to be the expensive part.

Generally, getting down from orbit is much cheaper than getting to orbit- say somewhere around 1/10th the cost or less.
If whatever you shipping from space to earth surface can withstand high gees- it's cheaper. 50 gees is a car accident. If payload can withstand over 100 gees, "landing" is more like a controlled crash. A controlled crash into a lake, could something with fairly high terminal velocity. And one major aspect is the accuracy of hitting say 10 sq kilometer area.
Normally, one want re-entry which is lifting body- to reduce gees [and heat- though heat isn't as challenging as gee loads].
« Last Edit: 02/26/2012 10:49 pm by gbaikie »

Offline Archer

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The first thing to manufacture in space is perhaps spacecraft. After all - they are so valuable that it is worth the cost of launching them to orbit.

Steve
Plants that build electronics costs billions on Earth, and market for satellites is very small. That's too much for a risky enterprise.

As for thought experiment of a factory in space. I am guessing you mean something which doesn't high volume- making drugs or something with low mass but is valuable. So perhaps 10 tons per year shipped to earth per year? With increase possible, perhaps to say 100 tons per year?
Exactly. I just don't know what small (both low mass and small dimensions) and expensive can be manufactured in space, that cannot be manufactured on Earth.
As far as I know only mining metals from asteroids can be profitable (if delivery from LEO to Earth surface is 100$/kg).

If whatever you shipping from space to earth surface can withstand high gees- it's cheaper. 50 gees is a car accident. If payload can withstand over 100 gees, "landing" is more like a controlled crash. A controlled crash into a lake, could something with fairly high terminal velocity. And one major aspect is the accuracy of hitting say 10 sq kilometer area.
Normally, one want re-entry which is lifting body- to reduce gees [and heat- though heat isn't as challenging as gee loads].
Good point about g-loads.
It seems that my factory will need 2 types of LEO-shuttles: one for workers (with gentle landing) and one hard-duty automated cargo truck.
« Last Edit: 02/28/2012 06:42 pm by Archer »
The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline Jim

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 The first thing to manufacture in space is perhaps spacecraft. After all - they are so valuable that it is worth the cost of launching them to orbit.


No, it is because it is cheaper to do it on the ground.  A factory in orbit is expensive.  I content it will be cheaper to recover raw materials from space on the ground, re-manufacture and launch for many decades* before it will be cheaper to do it in space.

* as long as humans have to be present.
« Last Edit: 02/28/2012 07:23 pm by Jim »

Offline savuporo

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One advantage of aerodynamic landing [ from LEO ] is that it has actually been done before.
Orion - the first and only manned not-too-deep-space craft

Offline Robotbeat

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One advantage of aerodynamic landing [ from LEO ] is that it has actually been done before.
So has powered (Soyuz), to a certain extent. More times than Shuttle, actually. Without parachute may be another matter, but it should be pointed out that that's essentially what MSL is doing... On Earth, a capsule's terminal velocity is about the same as what MSL will be on Mars with parachutes.
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Offline douglas100

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I wouldn't call what Soyuz does a powered landing. The solid retrorockets fire only a metre above the ground. It's more an impact attenuation device like an air bag. (And its failure means a very hard but not fatal landing.)

A powered landing would be something like DC-X or the Masten or Armadillo vehicles. And savuporo is right: that kind of manned landing hasn't been done yet.
Douglas Clark

Offline Robotbeat

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I wouldn't call what Soyuz does a powered landing. The solid retrorockets fire only a metre above the ground. It's more an impact attenuation device like an air bag. (And its failure means a very hard but not fatal landing.)

A powered landing would be something like DC-X or the Masten or Armadillo vehicles. And savuporo is right: that kind of manned landing hasn't been done yet.
Not from space, but it has been done with Harrier airplanes, etc. It happened several times during Apollo, of course (on the Moon). "Oh, well that doesn't count..." :)
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline douglas100

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Harriers don't count unless you are proposing a spacecraft that returns from orbit, deploys turbofans and executes a vertical landing!  :)

To be serious (and I think this has been said before) it's quite easy to imagine both approaches being used concurrently in different vehicles. If manned Dragon and Dream Chaser are both chosen and developed you would get an operational insight into the strengths and weaknesses of the two approaches. Whether this is likely I have no idea.

A similar comparison would arise of course, if SpaceX and the Air Force's reusable booster proposals were developed.
Douglas Clark

Offline nacnud

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I wonder what the trade of propulsive vs autogyro (with and without tip rockets) would look like these days.

Offline douglas100

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I wonder. Back to the days of Roton...
Douglas Clark

Offline RanulfC

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I wonder what the trade of propulsive vs autogyro (with and without tip rockets) would look like these days.
"Roto-Chute"
http://blog.modernmechanix.com/2007/01/29/roto-chute-for-rocket-pilots/

http://www.secretprojects.co.uk/forum/index.php?topic=9084.0

Several variants also including a "flexible" disk-rotor one, and one that used two deployable intermeshing rotors :)

Or you could go with THIS design:
http://www.highfrontier.org/Archive/Jt/Syromyatnikov%20-%20Hybrid%20Winged%20Reusable%20Spacecraft%20D2S2B-04Transports.pdf

(The "best" of both worlds! Capsule reentry and then transforming to a winged jet powered aircraft...)
Ok the Russians actually didn't think of this first here's an early American type design:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19700078267_1970078267.pdf

Note that this one "transforms" after reentry into a Mach-2 aircraft :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline douglas100

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These are interesting links.

As far as rotors are concerned, I believe there was a proposal in the early days of designing Vostok to use deployable rotors to land the capsule. This idea was quickly abandoned in favour of a parachute.

The only serious proposal to use rotors all the way through the atmosphere to landing was Roton. I'll say no more about that: there are posters on this forum with far more knowledge about Roton than me.

The capsule that converts into a lifting body seems like a bad idea. It is needlessly complex both in design and operation. Compare it with the simplicity of the CST-100 or Dream Chaser.
Douglas Clark

Offline RanulfC

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These are interesting links.
Thanks I hope to have more to come on various proposals :)

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As far as rotors are concerned, I believe there was a proposal in the early days of designing Vostok to use deployable rotors to land the capsule. This idea was quickly abandoned in favour of a parachute.
The same with the "Roto-Chute" concept, it was seen as "easier" to simply use well-known and tested parachutes instead. Times have changed and some of the "older" concepts are getting new looks...
 
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The only serious proposal to use rotors all the way through the atmosphere to landing was Roton. I'll say no more about that: there are posters on this forum with far more knowledge about Roton than me.
Actually....

The Roto-Chute and/or some other type of deployed rotor landing system was taken VERY seriously and extensive testing done in the early to mid-60s as this was seen as pretty viable system if somewhat complex in application. Extensive studies were done for rotor performance and technical risk mitigation from supersonic (@Mach-4) through Transonic to low-subsonic speeds and they were considered a viable option for the Apollo recovery but again the decision was made to go with standard parachutes. (Mostly due to continued gross mass growth of the Apollo capsule)

Volume-1 Subsonic:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710007058_1971007058.pdf

Volume-2 Transonic:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710007059_1971007059.pdf

Volume-3 Supersonic:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710007060_1971007060.pdf

The Society of Automotive Engineers has a 1963 report by the Kaman company:
"Test Results of Rotary-Wing Decelerator Feasibility Studies for Capsule Recovery Applications"
http://papers.sae.org/630382/

I'll probably pay the $23bucks this payday to download it...

A good "review" source on the various landing and recovery methods under consideration at NASA is this 1962 Compilation of presentations made to NASA HQ from the various centers:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19730061695_1973061695.pdf
(FYI: Rotary is pg 228-pg235)

There was a proposal around the mid-90s by Jeffrey Hagen at JSC for a Rotor Recovery System for the CEV, though the paper no longer seems available on the web. According to this 2011 Johnson Space Center article on rotor recovery:
http://research.jsc.nasa.gov/BiennialResearchReport/2011/82-2011-Biennial.pdf

They got some funding to do model tests in 2010 and it seems Rice University did some work on the concept also:
http://design.rice.edu/2011-Posters/Rotocapsule.pptx

As another "FYI" I should mention that rotary deceleration and landing systems (as well as on-planet movement) is still very much of interest for missions to Mars, Venus, Titan, and many other destinations.

ESA, "Armada" Mars mission:
http://robotics.estec.esa.int/ASTRA/Astra2008/S05/05_02_Graziano.pdf
http://robotics.estec.esa.int/ASTRA/Astra2008/S05/05_03_Lutz.pdf
http://esamultimedia.esa.int/docs/gsp/completed/C21233ExS.pdf

Titan:
http://www.planetaryprobe.org/SessionFiles/Session4/Papers/Steiner_Rotary_Wing-Paper.pdf

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The capsule that converts into a lifting body seems like a bad idea. It is needlessly complex both in design and operation. Compare it with the simplicity of the CST-100 or Dream Chaser.
Pretty much the same reaction I get from everyone on that design :) But again it's an "attempt" to get the "best" of both types of recovery. Practical? I've my doubts...

Of course lest I forget I should also point out that you actually CAN have the "best" of both worlds in one vehicle! (But then again we knew that "they" already knew this one ;) )

The "Lenticular" type vehicle pretty much reenters as a normal "blunt" capsule and transitions to hypersonic high-L/D flight all the way down to a "normal" landing on any land landing site. The design "technically" doesn't even need wheels as the heat-shield and rounded underbelly allow a fairly smooth oscillation during skid-out with a very efficent energy disipation.

Water landings as a "glider" are right out though. ANY wave action and the vehicle tends to either sky-rocket off the crests or flip/roll/skip all over the place.

Of course the way out of this is to simply deploy parachute or para-foil once the vehicle drops to low subsonic speed and use that for final velocity cancelation and touch-down. Again since it was considered a highly viable option for NASA they did extensive studies on the type. Note that they DO require a set of deployable "wings" or drag devices to maintain stabilty in transonic and subsonic velocity:

Landing Characeristics:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19980228014_1998386517.pdf

Stability, Mach-6 to around Mach-2:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19710070176_1971070176.pdf

Stability Mach-1.99 and below:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20020076018_2002124973.pdf

In 2005 Georgia Tech even used the base-line design as the basis of a Space Tourism concept:
http://www.nianet.org/rascal/forum2005/presentations/georgia_presentation.pdf

(This is pretty much the "original" Keck Lenticular Reentry Vehicle design for Apollo BTW. As a note it had the highest hypersonic L/D rating, even higher than the HL-10 Lifting body proposal!)

Of course as has been said before the original "question" can be answered quite simply with a simple; "Well, that all depends...." at which point you have to get down into the nitty-gritty of what you WANT out of the design in the first place :)

Me? UFO's for the "win" :D

Randy

From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline douglas100

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Again, very interesting links. (You learn stuff on this forum!)

So I should have said: "the only serious proposal to use rotors all the way through the atmosphere to landing that I know of is Roton."

The use of rotors is very attractive but the engineering challenges to using them to land a spacecraft seem formidable. Do you have the rotors extended in some way through the whole re-entry like Roton, or do you deploy them at low Mach numbers just before landing?

I've only glanced at the stuff you linked. Have studies been made where the rotors are exposed to re-entry heating? If you wish to avoid that and deploy the blades just before landing, how mechanically complicated would that be? And how safe would that be compared with ordinary parachutes?

No comment about the "UFO" shape! :)

Douglas Clark

Offline RanulfC

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No comment about the "UFO" shape! :)
Awwwww... That's the best one ;)

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Again, very interesting links. (You learn stuff on this forum!)
Again, you're welcome! (And I used to think you couldn't learn anything on the internet :) )

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So I should have said: "the only serious proposal to use rotors all the way through the atmosphere to landing that I know of is Roton."
Probably, but it would be simply petty to bring that up ;)

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The use of rotors is very attractive but the engineering challenges to using them to land a spacecraft seem formidable. Do you have the rotors extended in some way through the whole re-entry like Roton, or do you deploy them at low Mach numbers just before landing?

I've only glanced at the stuff you linked. Have studies been made where the rotors are exposed to re-entry heating? If you wish to avoid that and deploy the blades just before landing, how mechanically complicated would that be? And how safe would that be compared with ordinary parachutes?
Again it "depends" on the various assumptions on the design. In the majority of designs that assumed rotor use with blunt-body reentry it seems the "deploy-before-entry" method was prefered but the more recent concepts tend to favor deployable rotors at subsonic speeds. (Yes various materials were studied for the rotors and various methods for TPS and cooling during entry)

Roto-Chute was (as far as I can tell) simply going to use high-temperature materials, while ROTON was going to use active cooling (water) both for the heat shield and the rotors. ("Active" TPS tends to be less often proposed because of the feeling since it's "active" any failure or low performance would lead to disaster. As it's "active" rather than "passive" chances OF failure as assumed to be higher. But since "passive" systems tend to be "beefed-up" in order to avoid failure the difference is not as great as many assume)

As to comparing with a parachute, that seems to be the major reason that "other" methods tend to not gain traction. Parachutes (and wings) are KNOWN quantity and are both available and have well documented data to point to. Other methods, not so much.

Just about any landing method requires SOME type of "deployment" segment with some being less "critical" than others in a general way. (Sure, failure to deploy the landing gear on a winged vehicle probably means a serious situation but failure to deploy parachutes, rotors, whatever on a ballistic lander and the situation is pretty terminal)

In most cases it seems that suggested alternate methods of landing (rotor/powered/etc) vertically seem to include "parachutes" as a back up which begs the question if you're going to have them why not simply use them as the primary?

For one thing more than one system gives you failure tolerent "depth" where you can "afford" to lose a system and still recover more or less intact. Even "standard" parachute systems often use this strategy relying on more 'chutes than required in case of a failure.

There is also the issue of controlabilty and guidance where a suggested system allows more accuracy than "normal" parachutes.

In the end it really comes down to the subject of this thread in weighing the "advantages" and "disadvantages" of various factors between systems and between what is desired for the outcome.

Like all things, the answer does tend to come down to simply "It depends" with the solution being highly dependent on what assumptions are being used, what results are desired, and what factors are being considered.

I've seen it "said" over and over again that "wings" (lifting) landing enhance reusablity because you don't have to re-pack the parachutes, But that is such a simplistic comparision as to be useless, and pretty much just highlights an assumed bias.

We have decades of experiance inspecting, packing, and using parachutes so the process' themselves are well known, highly understood, and (probably most important) with well documented and known data readily available. Mounting a fully certified "new" parachute in place of a used one would be a relativly straight-forward task and easily intergrated with the rest of the required vehicle refurbishment in getting ready to re-launch.

"Aerodynamic vehicles have greater cross-range" is another one which tends to disguise a bias rather than a real "factor" since in general the one who quotes this is refering to a winged vehicle veresus a ballistic capsule, but which ignores several dozen questions relating to "aerodynamics" and "cross-range" :)

Spacecraft are generally designed with SOME "aerodynamic-lift" if for no other reason than to reduce the G-stress' of reentry. However "cross-range" wise the Spacecruiser:
http://www.up-ship.com/apr/extras/scruiser1.htm
"spaceplane" had a higher "cross-range" than the Shuttle and it didn't have wings. It would be able to perform manuevers in the upper atmosphere and propulsively return to orbit which the Shuttle can't do. (And as the X-37 is suggested to do but that's another "thing" :) )

What it could NOT do is "fly" aerodynamically at low-supersonic/subsonic speeds. For that it needed a "parachute" (parafoil actually) and also to land. With a high hypersonic "L/D" it could perform manuvers at much greater velocities where "energy-wise" you get more bang-for-your-buck than supersonic or subsonic. But you "pay" for that at the lower speed ranges, hence the need for parachutes to land with.

But again, that's part of the "needs" driving the design; the Space Shuttel was designed around the "needs" of low-speed handling and landing requirements while the Spacecruiser was designed with other criteria in mind.

"Wings give you more surface area so are easier to design for Low-G/Low-Stress reentry and landing" is another one where you can USE any system to get the result. Soyuz/Apollo/Gemini/etc all used "lift" during reentry to effect g-loads and reentry heat levels the same way the Shuttle did. Again that's a "design" factor not inherent to any one type of vehicle.

We've KNOWN about ballistic coefficent ratio for those factors even before we launched the fist spacecraft, but actually applying it as a design factor has been limited at best.
REALLY want to ensure your payload has the most gentle ride possible? Fine, use a "Para-Shield":
http://microsat.sm.bmstu.ru/e-library/etc/bremsat2.pdf
http://spacecraft.ssl.umd.edu/publications/2010/SpaceOps2010ParaShieldx.pdf
http://www.nianet.org/rascal/forum2006/presentations/1010_umd_paper.pdf
http://www.planetaryprobe.org/SessionFiles/Session4/Papers/Rohrschneider_Inflat&Deploy-Paper.pdf

But it's not really compatable with an aerodynamic landing, so anyone looking for an excuse to use wings or aerodynamic lift is going to gloss right over that...

"Capsules aren't reusable" which is right out there, because again it's design factors. We haven't needed or wanted a "reusable" capsule yet so none have been built. Technically there is not reason a capsule can't be just as "reusable" as a winged or lifting body vehicle.

And those are just a few (very few) of the various "factors" that need to be considered and/or designed to. And pretty much why the ONLY answer in total honesty to the OP question ends up being "It Depends" and why the debate will continue for a LONG, long time to come :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline Archer

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RanulfC
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Of course as has been said before the original "question" can be answered quite simply with a simple; "Well, that all depends...." at which point you have to get down into the nitty-gritty of what you WANT out of the design in the first place
At the first place I want lowest price for bringing goods from LEO down to Earth surface)

Ineresting links, thank you. Sounds very complicated though.
The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline RanulfC

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Ineresting links, thank you. Sounds very complicated though.
If it weren't complicated then everybody could do it :)

Seriously, it's all in the "details" which makes it VERY complicated but even more so when assumptions and bias' get in the way.

That's why we all sit back and let Jim design everything ;)

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RanulfC
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Of course as has been said before the original "question" can be answered quite simply with a simple; "Well, that all depends...." at which point you have to get down into the nitty-gritty of what you WANT out of the design in the first place
At the first place I want lowest price for bringing goods from LEO down to Earth surface)
Oh that ones easy! Don't put it in LEO in the first place! Then you just use FedEx to ship it around....
::::grin::::

Again, seriously (really I mean it this time) a ballistic capsule ala-Soyuz type vehicle sans all the manned parts and "extra" equipment is probably the best bet. That should work up to a ton or so. After that you want to probably find a way to "build" and "attach" a simple foamed-metal heat-shield onto your cargo and dump it into the ocean.

Now having said that, I didn't take into account G-loads, packing, WHAT the cargo is, or WHY you had to make it in orbit either. So your-milage-may-vary... A lot :)

Randy
From The Amazing Catstronaut on the Black Arrow LV:
British physics, old chap. It's undignified to belch flames and effluvia all over the pad, what. A true gentlemen's orbital conveyance lifts itself into the air unostentatiously, with the minimum of spectacle and a modicum of grace. Not like our American cousins' launch vehicles, eh?

Offline colbourne

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Inflatable spacecraft makes successful splash landing

http://www.newscientist.com/article/dn22094-inflatable-spacecraft-makes-successful-splash-landing.html

The vehicle travelled some 450 kilometres over the Atlantic Ocean, outside Earth's atmosphere. The 308-kilogram inflatable heat shield – or aeroshell – separated from the nose cone of its launch vehicle and was then inflated with nitrogen into a mushroom shape before falling through Earth's atmosphere.

"The launch went perfectly," says Stephen Hughes of NASA's IRVE-3 team.

Planned initially to enable the exploration of higher-altitude terrain on Mars, the IRVE-3 team is also anticipating its use as a link between here and the International Space Station, transferring waste and other cargo.

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