Author Topic: What are advantages and disadvantages of powered and aerodynamic landing?  (Read 38868 times)

Offline Archer

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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).
« Last Edit: 02/21/2012 07:33 pm by Archer »
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Offline go4mars

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Wings are heavy, but provide more cross-range if that is needed. 
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Offline kevin-rf

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Doesn't this belong in the advanced concept section, as it applies to more than just spaceX?
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Offline Lee Jay

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

Wings are orders of magnitude more efficient at generating lift than rocket fuel and engines are.

Offline AbeJ

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It seems to me to be a tough sell to justify carrying the mass of all the fuel needed for powered landing all the way up to LEO. 
I've also wondered about the extra heat shielding needed for the exhaust plume as the vehicle nears touchdown - especially for returning launch stages which don't have re-entry shielding, as has been proposed.
I think, for the scenario proposed here, aerodynamic would be the way to go - especially in a reusable form such as Dreamchaser.

Offline Robotbeat

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

Wings are orders of magnitude more efficient at generating lift than rocket fuel and engines are.
Over long distances, maybe. But not for small amounts of lift just for landing, especially if you have the rocket engines and tanks and everything anyway. In that case, it's just a case of making the whole thing a little higher performing versus making your entire vehicle completely different with completely different load paths and different orientations, etc.

If you need 10-30 seconds of thrust to land, you need 10-30 seconds of fuel. If you need to land, your wings are still huge.

The trade is pretty close, though. Different folks are trying it different ways. I still sort of side with the vertical landing folks... Wings are dead weight in space.


May the best design win!
« Last Edit: 02/22/2012 03:23 am by Robotbeat »
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Offline Lee Jay

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Over long distances, maybe. But not for small amounts of lift just for landing, especially if you have the rocket engines and tanks and everything anyway.

In that case, nearly all of the delta-V comes from aerodynamics, and that's because wings (even they they are low-aspect-ratio ones like capsules) are more efficient than rocket fuel and engines.

Offline Proponent

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As has been said before, if you're flying very frequently, then the cross-range provided by wings is pretty valuable, because it potentially allows you to return to the launch site on each orbit.  With propulsive landing, however, you might have to wait a day for your orbital track to pass over the launch site.  I think it's going to be a while, though, before flight rates are high enough that an extra half day or so in orbit is a significant drag on the economics of an orbital transportation system.

There's also the question of launch abort.  SpaceX's Dragon shows how the landing system can double as a launch escape system.  Intact abort for a winged vehicle is potentially a little trickier, since for low-altitude aborts the winged vehicle is going to need a pretty powerful boost to get it and its wings up to flight speed.

Wings represent a large area requiring thermal protection on re-entry, which can be problematic as we saw with Columbia.  On the other hand, by presenting a large area on re-entry, the winged vehicle may get away with lower temperatures and hence cheaper, more durable materials over much of its wings than the a capusule would require over its smaller heatshield.

I guess I'm a powered-landing guy myself, but I think it's great that both approaches are being actively pursued (e.g., CST-100, Dragon, Orion for powered, Dream Chaser for winged).
« Last Edit: 02/22/2012 04:46 am by Proponent »

Offline colbourne

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Fuel is a low cost part of a space launch system. Musk reckons the re-usability of his craft will more than out weigh the extra fuel cost.

The choice between wings and rockets will vary between the various planets/moons being landed on.

If coming from orbital velocity, aerobraking saves a lot of fuel and wings can be required to make this feasible on some planets.

Designing a craft to land on Mars without a massive fuel requirement for this process should be a top priority as any weight saved in landing will make a huge difference to the take off mass from Earth.

Offline Robotbeat

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Over long distances, maybe. But not for small amounts of lift just for landing, especially if you have the rocket engines and tanks and everything anyway.

In that case, nearly all of the delta-V comes from aerodynamics, and that's because wings (even they they are low-aspect-ratio ones like capsules) are more efficient than rocket fuel and engines.
Yup, for high delta-v lift, there's an advantage. At low delta-v, there's a certain mass for wings. You just need a little bit of fuel, on the other hand, if you go propulsively.
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Offline douglas100

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The trade is pretty close, though. Different folks are trying it different ways. I still sort of side with the vertical landing folks... Wings are dead weight in space.

May the best design win!

Agree that the trade is close. I prefer wings for aesthetic reasons, but I also agree that vertical landing has its merits. (I thought the latest video of Xaero was very cool.)

I could even imagine both approaches being used in different contexts.
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Offline douglas100

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One advantage of wings that has been mentioned is a potentially softer landing for ISS crew after 6 months on orbit. The Soyuz landing is pretty brutal.
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Offline go4mars

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Away from Earth, wings are a disadvantage almost all the time.  SpaceX wants to have Mars capable hardware and systems (as much as possible).
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Offline Proponent

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One advantage of wings that has been mentioned is a potentially softer landing for ISS crew after 6 months on orbit. The Soyuz landing is pretty brutal.

But there's no reason a powered landing can't be gentle -- consider the Apollo LM, for example.

Offline grakenverb

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This looks extremely difficult for a whole variety of reasons.  I can see the first and second stages having enough fuel left to make the return journey, but I can't imagine that there would be enough room in the Dragon for the fuel required for powered descent.  I thought they would go with a combination of parachutes to slow Dragon, then the Super Dracos for the last 30 or 40 thousand feet.







BTW:  Has there EVER been a spacecraft that has returned from Earth orbit using powered descent all the way to the surface?
« Last Edit: 02/22/2012 06:06 pm by grakenverb »

Offline douglas100

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Away from Earth, wings are a disadvantage almost all the time.  SpaceX wants to have Mars capable hardware and systems (as much as possible).

I am taking the title of the thread to mean aerodynamic landing on Earth. There are other threads for discussing Mars landing techniques.
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Offline Robotbeat

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Away from Earth, wings are a disadvantage almost all the time.  SpaceX wants to have Mars capable hardware and systems (as much as possible).

I am taking the title of the thread to mean aerodynamic landing on Earth. There are other threads for discussing Mars landing techniques.
We're interested in going beyond Earth, so it's relevant if the same techniques can then be applicable for other worlds besides the Earth.

...for extremely high Mars entry speeds, wings with their higher hypersonic lift/drag (used "negatively") can help keep the entry craft from skipping off into space. But that's a pretty extreme example.
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Offline douglas100

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But there's no reason a powered landing can't be gentle -- consider the Apollo LM, for example.

That's true. The comment I made was based (I think) a claim made by SNC about Dream Chaser. And being Devil's advocate for a moment, and speaking against my own preference, powered landing has the advantage of not needing a runway-any reasonably level piece of terrain will do.

On the other hand, a winged landing means that all propellant on board can be burned or vented before landing, greatly reducing the risk of fire or explosion in the event of a hard impact. A powered lander must land with prop on board. I remember the DC-X trying to land on three legs, falling over and being engulfed in flame.

I think I still (slightly) favour wings...
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Offline douglas100

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...for extremely high Mars entry speeds, wings with their higher hypersonic lift/drag (used "negatively") can help keep the entry craft from skipping off into space. But that's a pretty extreme example.

It is. And wings cannot be used for landing on Mars by themselves, of course. So I hold to my point that if we are talking about aerodynamic landing (I take that to mean winged landing, not parachutes), we are talking about landing on Earth. (OK, we might mention Titan, in which case we might make the lander a seaplane.  :))

Aerodynamic maneuvering is a different matter and can in principle be carried at any Solar System  body (excluding the Sun!) which has an atmosphere.
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Offline Robotbeat

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...for extremely high Mars entry speeds, wings with their higher hypersonic lift/drag (used "negatively") can help keep the entry craft from skipping off into space. But that's a pretty extreme example.

It is. And wings cannot be used for landing on Mars by themselves, of course. So I hold to my point that if we are talking about aerodynamic landing (I take that to mean winged landing, not parachutes), we are talking about landing on Earth. (OK, we might mention Titan, in which case we might make the lander a seaplane.  :))

Aerodynamic maneuvering is a different matter and can in principle be carried at any Solar System  body (excluding the Sun!) which has an atmosphere.
The title asks:
"What are advantages and disadvantages of powered and aerodynamic landing?"
One of the advantages of powered landing (vs aerodynamic) is that it can be done at places other than Earth. To artificially exclude the rest of the solar system is to deny one of powered landing's best advantages. We're going to have to get good at powered landing anyway.

Another is that wings are generally pretty heavy and are only really very good at returning from LEO. Do we really want to be restricted to only returning from LEO?
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Offline antiquark

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Don't think anyone mentioned this yet, but wings are pretty reliable compared to rocket engines.  Wings are simple chunks of metal with few moving parts, whereas rockets are complicated chunks of metal with lots of moving parts.


Offline Robotbeat

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Don't think anyone mentioned this yet, but wings are pretty reliable compared to rocket engines.  Wings are simple chunks of metal with few moving parts, whereas rockets are complicated chunks of metal with lots of moving parts.


Columbia was a loss-of-crew-event because of wing failure (due to debris impact... wings present extra area which can be hit by debris).
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Offline Namechange User

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And engines can explode for any number of reasons.....

It's a trade that depends on many factors and one that definitively will not be answered on this thread.
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Offline antiquark

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Here's a thought experiment to put it into perspective: imagine you had a wingless space shuttle. What kind of engines, and how much fuel, would be needed for a vertical landing?

Offline Namechange User

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Why would anyone have a "wingless space shuttle"?  If it did exist, it wouldn't be the "space shuttle" anyway and therefore how many engines, amount of prop, etc would be a completely different context. 
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Offline deltaV

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Don't think anyone mentioned this yet, but wings are pretty reliable compared to rocket engines.  Wings are simple chunks of metal with few moving parts, whereas rockets are complicated chunks of metal with lots of moving parts.

On the other hand it's easier to design for engine-out than for wing-out.   ;)

Offline Namechange User

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Don't think anyone mentioned this yet, but wings are pretty reliable compared to rocket engines.  Wings are simple chunks of metal with few moving parts, whereas rockets are complicated chunks of metal with lots of moving parts.

On the other hand it's easier to design for engine-out than for wing-out.   ;)

But that whole argument of "wings get hit by debris" is a bias looking for justification. 

Yes, it happened in the past.  But windows get hit by birds on aircraft take-off.  There is a risk there but it gets mitigated by any number of ways.  Same with powered-landings.

So a particular tactical solution to the design is based partly on the strategic reason for the vehicles existance in the first place and the overall concept of operations.

It is ok to have more than one solution. 
« Last Edit: 02/22/2012 07:03 pm by OV-106 »
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Offline antiquark

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Just imagine you're designing a wingless spacecraft that has the same capabilities as a shuttle orbiter:

http://en.wikipedia.org/wiki/Space_Shuttle_orbiter

For example, the "wingless shuttle" would have a crew of 8, max payload of 55,000 lbs, payload bay that is 60 ft long, etc, etc.

Based on my crude calculations, it would need ~100,000 lbs of fuel for a rocket-powered landing. So actually wings might be more efficient in this case.



Offline A_M_Swallow

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{snip}

Another is that wings are generally pretty heavy and are only really very good at returning from LEO. Do we really want to be restricted to only returning from LEO?

The spacecraft could use a mixed system - engines to slow down from escape velocity to just under LEO velocity and use wings for the rest of the landing.  The wings would be replacing the parachutes.

This slow down would require a delta-V of about 3.23 km/s to trigger re-entry plus extra fuel for manoeuvring.

I will leave it to other people to decide if the extra mass is worth while.

Offline douglas100

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The title asks:
"What are advantages and disadvantages of powered and aerodynamic landing?"
One of the advantages of powered landing (vs aerodynamic) is that it can be done at places other than Earth. To artificially exclude the rest of the solar system is to deny one of powered landing's best advantages. We're going to have to get good at powered landing anyway.

Another is that wings are generally pretty heavy and are only really very good at returning from LEO. Do we really want to be restricted to only returning from LEO?

I am not artificially excluding the rest of the Solar System. The title "What are advantages and disadvantages of powered and aerodynamic landing?" is meaningless applied to bodies without an atmosphere. Such bodies are automatically excluded from such a discussion. And of course we are going to have to use powered landing for them.

I am only commenting on landing on Earth from LEO. As I said earlier, there are pros and cons on both sides but I still slightly favour wings.
« Last Edit: 02/22/2012 10:41 pm by douglas100 »
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Offline douglas100

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Actually, OV has it right:

Quote
It's a trade that depends on many factors and one that definitively will not be answered on this thread.
Douglas Clark

Offline Robotbeat

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...
I am not artificially excluding the rest of the Solar System. The title "What are advantages and disadvantages of powered and aerodynamic landing?" is meaningless applied to bodies without an atmosphere. Such bodies are automatically excluded from such a discussion. And of course we are going to have to use powered landing for them.

And again, one of the advantages of using powered landings on Earth is that the knowledge can be extended to allow the same technique in other places, allowing you to get more return on your investment. That still counts as an advantage, even if you're using it primarily on Earth.

And of course I agree that some little web forum thread won't decide the issue (was that ever in doubt?).

Virgin Galactic and XCOR and Skylon (and others) are attempting the HTHL approach, SpaceX and Blue Origin and Masten (and others) are attempting the VTVL approach. I happen to think the VTVL approach is better (for orbital). But smart people are trying both ways.
« Last Edit: 02/22/2012 10:52 pm by Robotbeat »
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Offline Robotbeat

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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).
It kind of depends on the product, actually.

One thing you have to realize is that all aerospace engineers have to learn all about wings and aerodynamics, etc. They don't have to learn as much about rockets, etc. That's probably partly why you see so many people saying they like the look of wings, that they're cooler, etc... People (engineers and aerospace enthusiasts) are more familiar with wings. That doesn't mean wings aren't a better solution, just that you might want to take that into account to explain the popularity of wings in some circles.

The US Air Force (who deals largely with winged vehicles, obviously) commissions flyback boosters (i.e. horizontal landing). SDIO (DoD missile guys) did DC-X (vertical landing). When you have a hammer, everything looks like a nail.
« Last Edit: 02/22/2012 11:08 pm by Robotbeat »
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Offline Proponent

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This looks extremely difficult for a whole variety of reasons.  I can see the first and second stages having enough fuel left to make the return journey, but I can't imagine that there would be enough room in the Dragon for the fuel required for powered descent.

The idea with Dragon is that the same propellant supply is used for launch abort, for in-orbit maneuvering and de-orbit, and for landing.  At most two of those three will be done on any one flight.

Quote
I thought they would go with a combination of parachutes to slow Dragon, then the Super Dracos for the last 30 or 40 thousand feet.

The way powered descent and landing is usually envisioned is that the vehicle falls to a low altitude -- like a few kilometers.  No parachutes are used, but drag still slows the the vehicle to below the speed of sound.  Then the engines are lit for, say 30 seconds, during which time the vehicle decelerates at 1 G or so and touches down gently.  Thus, there's no need to ignite the engines at high altitude, and the time that they need to burn is actually pretty short.

I suppose it might be the case that a returning Falcon first stage would perform a braking burn a high altitude (over 100,000 ft) so as to re-enter the atmosphere more slowly (since Falcon first stage apparently have a hard time staying in one piece during Mach 10 re-entries), but the engine would surely then be extinguished (or maybe kept running at very low thrust) until landing.
 
Quote
BTW:  Has there EVER been a spacecraft that has returned from Earth orbit using powered descent all the way to the surface?

So, no, no powered landing would involve continuous thrusting from orbit down to the ground.
« Last Edit: 02/23/2012 01:14 am by Proponent »

Offline JohnFornaro

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One advantage of wings that has been mentioned is a potentially softer landing for ISS crew after 6 months on orbit. The Soyuz landing is pretty brutal.

But there's no reason a powered landing can't be gentle -- consider the Apollo LM, for example.

Of course, that was one sixth gee and no atmo, so not too comparable to an Earth landing. 

It's a complicated trade... I dont' know how to figure it.
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Offline Andrew_W

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Soyuz 1 hit the ground at less than 100mph with tangled drogue and reserve 'chutes. So if it's only terminal velocity you have to break against, you're probably talking about less than 10% of the re-entry mass needing to be propellant, wings would weigh more than that, heat shield is still required with both methods.
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Offline Robotbeat

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Soyuz 1 hit the ground at less than 100mph with tangled drogue and reserve 'chutes. So if it's only terminal velocity you have to break against, you're probably talking about less than 10% of the re-entry mass needing to be propellant, wings would weigh more than that, heat shield is still required with both methods.
...and wings which can survive reentry are not trivial.
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Offline nacnud

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IIRC I saw a web page that described some early designs of the Russian shuttle before it was decided to use the Buran design.

The preferred design was a lifting body that used rockets for landing, I'll try to find it again.


Offline antiquark

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IIRC I saw a web page that described some early designs of the Russian shuttle before it was decided to use the Buran design.

The preferred design was a lifting body that used rockets for landing, I'll try to find it again.



Found it!

http://www.astronautix.com/craft/buran.htm

"their preferred 1974 design was an unwinged spacecraft, consisting of a crew cabin in the forward conical section, a cylindrical payload section, and a final cylindrical section with the engines for maneuvering in orbit. This unwinged MTKVA would glide to the landing zone at low subsonic speed. The final landing maneuver would use parachutes for initial braking, followed by a soft vertical landing on skid gear using retrorockets."

Offline nacnud

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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.


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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 »
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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.
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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..." :)
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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.
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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.

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I wonder. Back to the days of Roton...
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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.
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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 ;)

Quote
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
Quote
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 ;)

Quote
RanulfC
Quote
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.

Offline gospacex

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Forgive my ignorance, but is it possible to pull on parachute suspension lines just before capsule touch-down, in order to reduce impact forces?

How much such a device would weigh?

Offline douglas100

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I believe such a device was discussed somewhere but I can't remember where. In principle there seems no reason why it shouldn't work, but in the big bad world of real engineering, that's a different matter...
Douglas Clark

Offline Rocket Science

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I believe such a device was discussed somewhere but I can't remember where. In principle there seems no reason why it shouldn't work, but in the big bad world of real engineering, that's a different matter...
It was done on the X-38, with electric actuators...
"The laws of physics are unforgiving"
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Offline Robotbeat

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I believe such a device was discussed somewhere but I can't remember where. In principle there seems no reason why it shouldn't work, but in the big bad world of real engineering, that's a different matter...
It was done on the X-38, with electric actuators...
It is done for landing military payloads as well, I think usually with a sort of pneumatic "muscle" device.
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Offline savuporo

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It is done for landing military payloads as well, I think usually with a sort of pneumatic "muscle" device.
I though that these guys used regular servos.
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Offline Robotbeat

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It is done for landing military payloads as well, I think usually with a sort of pneumatic "muscle" device.
I though that these guys used regular servos.
I don't know what they use (if anything).

But the idea of using a pneumatic muscle for landing is a relatively old one, dating back to 1949:
http://faculty.nps.edu/oayakime/ADSC/AGAS%20-%20Brown%20-%20A%20New%20Pneumatic%20Actuator.pdf
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 savuporo

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Well, you have to have something for steering anyway, just two servos pulling the toggle lines. So the same servos will flare and land as well.
Not sure what advantage a pneumatic system would give you there, over a regular electromechanical linear servo or for example an SMA actuator
Orion - the first and only manned not-too-deep-space craft

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