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Possible Craft

Posted by: Sev - Sun Oct 10, 2004 4:10 pm
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Possible Craft 
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Post    Posted on: Thu Dec 23, 2004 11:34 am
I mentioned the rescue or recovery of upper stages orbiting the Earth several posts ago in this thread.

There is reason now to consider that idea again. According to the article "At the end of February, SpaceX’s Falcon 1 rocket will make its maiden voyage with some 125 civilian passengers." ( http://news.com.com/Space:+Final+fronti ... 98693.html ) under www.xprizenews.org Space Services - using SpaceX's Falcon I - says that "...The orbit..." of "...the final stage of the rocket... ...lasts more than 10 years...".

This may be sufficient time for Ball to get their ballute technology ready. If they manage to do that really there could be privately funded vehicles perhaps using this technology. These vehicle could get into the orbit close to that final stage, catch it cautiously and then use the ballute to slow down to velocities where safe reentry is possible.

When the ballute technology is ready it might be possible to make it available to the final stages directly...

These are thoughts based on the information according to the article and on the ballute technology only.



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Post    Posted on: Thu Dec 23, 2004 3:33 pm
Ekkehard Augustin wrote:
This may be sufficient time for Ball to get their ballute technology ready. If they manage to do that really there could be privately funded vehicles perhaps using this technology. These vehicle could get into the orbit close to that final stage, catch it cautiously and then use the ballute to slow down to velocities where safe reentry is possible.


Whether it's possible or not doesn't matter. The problem is that it's stupid.

The upper stages are SHELLS. They're a wrapper placed around some oxidizer, propellant and an engine. Bringing them back to earth for refurbishment will cost more than manufacturing a new one. What you're talking about would be possible in the same sense that it would be possible to re-use the cardboard box the McDonald's Quarter-Pounder I had for lunch yesterday came in. You just need someone to retrieve it from the dumpster, carefully uncrumple it, then clean and sanitize it. Possible, but not economical.

The primary value in upper stages in orbit is the fact that they're in orbit. If we're able to develop orbital manufacturing with the capability to make use of such materials -- they will be worth their weight in gold. Bringing them down to earth makes them worth their weight in aluminum -- except that you just paid their weight in gold to bring them back to earth.


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Post    Posted on: Fri Dec 24, 2004 9:10 am
All of this - or nearly all I know very well. I myself have been arguing like this already.

But regarding the ASP it is required to provbide a very high degree of reusability and there have been doubts wether this is possible if the upper stages are lost in space or burnt at reentry. So rescuing or recovering the upper stages ccould be a good assistance in fulfilling the reusability requirement.

Another reason to capture upper stages still is that they are dangerous orbital debris as long as they are going along thei orbits. Already the actual amount of orbital debris counting up to more than 170,000 objects is considered to be dangerous - all the very small debris like screws etc. not included. The reusability rule could help to prevent more debris.

An additional argument for bringing upper stages back to the surface is that multiple stage vehicles require upper stages each launch again. To bring back these stages means that no immediate production of new stages is required and no place to store them is required. All this could help to keep the costs and the investment low.

This could outweigh the value of leaving the stages in orbit.



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Post    Posted on: Fri Dec 24, 2004 10:48 am
If you could "harvest" the orbiting upper stages you might be able to reprocess them into something more useful, like the basis for an orbiting platform (the Russians are talking about putting a platform in orbit to act as a space dock but with their finance problems I cant see it happening).

It might be possible to melt the aluminium using a solar furnace to produce support structures for orbiting stations. One problem might be that the processing causes even more small pieces of debris in orbit though.

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Post    Posted on: Sat Dec 25, 2004 9:09 pm
Hello, andy Hill,

you are pointing to a similar direction of thoughts I have in mind. All you are mentioning is a possible good purpose to use the orbital debris and the upper stages for.

All the stages and all the debris should be distributed economically over the purposes - by criteria like price, costs etc.

All this will leave stages and debris fr purposes the Russians, you or mrmorris or someone else have in mind - and it will leave stages for reuse to launch vehicles.

To reuse stages for launching vehicles saves productin costs as well as costs of transforming stages into platforms. The criterion is the comparison between rescue costs on one side and transformation costs on the other side. And the ballutes will reduce the rescue costs supposedly.

Once there is orbital tourism reusability will be of very high meaning.



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Post    Posted on: Sun Dec 26, 2004 10:07 am
This is another point to think about. If space turism is going to be a success then the craft cannot be using disposable upper stages as these would eventually fill up the orbits with junk and become a hazard.

If the first vehicles have such stages then these will have to be constantly removed from orbit.

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Post    Posted on: Mon Dec 27, 2004 12:23 pm
In principle the arguments pro and contra rescue of stages, making use of orbital debris in space and other aspects have be collected and faced to the real requirements. This should be done by the market.

Each first step is to have access to space and especially to the orbit.

If this will be possible by SSTO in the nearby future no upper stages are required. So no upper stages will be placed into an orbit - no rescue possible, no rescue required and no stage available to be transformed into platforms or other space equipment.

If in turn it cannot be achieved by SSTO each launch will require an upper stage and the rescue of each stage and to reuse it at launch can save production costs and provide economies of scale - a comparison is required and should be done by the market because entrepreneurs will compete to find the way to the least possible costs and the maximum of economes of scale. Then platforms etc. for space have to be produced separate but no transforming work in space is required. This last point may make space missions cheaper because modifying work in space without assistance of robots is possible - there has been proof by the work o the ISS.

There are already many stages and other debris in orbit - this should be used first. And this will tend to cleanse the orbit.


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Post    Posted on: Mon Dec 27, 2004 1:39 pm
I think that the SSTO vehicle is not going to appear for a while yet and that alternative could use an "Armadillo stage" type vehicle to lift a craft to space where it would be released and fire its own engine to achieve orbit the "Armadillo stage" would return to earth making a suborbital flight.

The released spacecraft would incorporate an upper stage that carried enough fuel to gain the velocity necessary to achieve orbit. I noticed that the engines and bottom of the Delta IV common core boosters were covered in an ablative material to protect them from the heat, could this technology be used as a heat shield so that the returning spacecraft could enter the atmosphere upper stage engine first to deflect the heat. At a suitable height and velocity during reentry the spacecraft could separate from the upper stage and both could return to earth using a parachute system to be reused.

The armadillo spacecraft has been developed for suborbital flights and would only need to be scaled up to launch a large enough craft to a point where it could achieve orbit. Perhaps this is what Armadillo themselves envisage for an orbital craft.

This approach would mean that much more of the craft would be reusable, complying with ASP rules, and that there would be no upper stage left in orbit.

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Post    Posted on: Mon Dec 27, 2004 2:04 pm
There would be an economical advantage too: the suborbital tourists would pay for the propellenat and the depreciation of the suborbital stage.

I would like this alternative - its economical efficient as well is it technical.



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Post    Posted on: Mon Dec 27, 2004 3:28 pm
I've just had a look at the upper stages used on Delta IV medium rockets which appear to be a close match (or my best guess) to what might be required to accelerate a craft into orbit from the Armadillo stage I proposed.

The weight of an upper stage for a Delta IV medium is about 24,000kg, this would probably mean that the combined weight of the craft and upper stage would be approx 30,000kg. I'm not sure that Armadillo's vehicle could be scaled up that much, but it would not have to carry the same weight on the descent as it would have lost the crew vehicle and upper stage.

This is akin to some of the ideas I've seen posted with platforms orbiting in LEOs to launch from but with the Armadillo craft acting as a non-orbital platform.

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Post    Posted on: Sat Jan 01, 2005 5:59 pm
That reminds me to an old concept Wernherr von Bruan had worked out for reusable vehicles. He provided a manned orbiter stage and a first stage that was manned too. I saw an artist's image of the concept.


The differende to using Black Armadillo as a suborbital launcher platform is that von Braun'S first stage was winged as well as the orbiter stage.

This now is causing me an idea similar to both von Braun and your idea. Compare Scaled's Wight Knight/SpaceShipOne concept and Rocketplanes airplane-concept. Rocketplane is trying to do single-staged what Scaled has done double-staged. If Rocketplane will succeed - what about developing a Wight Knight-pendant out of that vehicle then and to carry an orbiter into space this way?

I know all the arguments against air launches into orbit - but Black Armadillo is as well suborbital as WK/SSO and there are onlx slight differences between these vehicles once they are in space.



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Post    Posted on: Sat Jan 01, 2005 6:12 pm
This is similar to the concept that ESA and EADS are looking at to launch satellites, cant remember the name at the moment (probably to much Christmas Pudding) but Pheonix was a demonstrator for the same project.

I must admit this seems a much better idea than using an EELV or some other big booster to put a manned craft in to orbit.

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Post    Posted on: Sun Jan 02, 2005 4:19 pm
If the concept of manned first stage plus manned orbital stage will work well - what about using this concept for reentry of the orbital stage then? The orbital stage could use the heat shield or other heat protection system of the suborbital stage at least partially in this case.

And passengers paying for a flight by the suborbital stage would contribute a second portion to the costs of the orbital stage - it would be just a repetition of the economic advantage at the launch.

I take into account that the orbiter stage is decelerated by ballutes or something similar before it redocks to the suborbital stage.

The suborbital stage would have to get some navigational capabilities in this case.



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Post    Posted on: Sun Jan 02, 2005 7:28 pm
I dont think that is really necessary, because you would have to slow the orbital craft down so much to rendezvous with the suborbital craft you would probably no longer need the heatshield and so could just fly it back on its own.

Also the timing would be critical as the sub orbital craft would only be in space for a few minutes and it is not at a constant height. It seems like a lot of unnecessary effort when if the orbital craft has lost most of its velocity it can glide to the nearest runway.

I cant see an economic advantage when you would have to make both craft more complicated and not have flexibility to alter launch windows once the orbital craft had deployed a balute. You would probably need to be able to track the craft from half way around the earth rather than locally when it came in to land, this would increase your costs by having much more infrastructure to maintain.

From a safety aspect you would want to make the orbital craft land on its own because if it missed the rendezvous or was unable to attach itself to the sub orbital craft what would happen to the people on board?

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Post    Posted on: Mon Jan 03, 2005 7:29 am
It was to check it out only.

And I recognize that I randomly mentioned another aspect than I had in mind - if the orbital stage would be launched as well as returned by the suborbital stage the orbital stage wouldn't need wings.

Under the aspects you are mentioning the economic advantages will become dependent of the number of suborbital flights and the number of orbital flights and their date and time. When there are millions of flights the timing required might be caused by the market(s) and become stable perhaps. But it's no doubt an academic consideration for the first time.



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