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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: Mon Oct 25, 2004 2:22 pm
Ekkehard Augustin wrote:
If there is no concept of the particle beam propulsion engineering now - can there be one in a couple of years? Why can't it be applied to suborbital spacecrafts that reach altitudes of several hundred or thousand kilometers?


I didn't say that there *is* no concept of it, I said that *you* had no concept of it. The only reason it sounds plausible to you for accelerating and decelerating crafts to and from orbit is because you don't really understand it.

Consider this idea -- we build a giant fan to blow huge quantities of air at hundreds of miles an hour straight up. We then build a spacecraft that has a giant parachute attached. The fan will provide the motive power to accelerate the spacecraft to orbit.

Presumably (I hope), you know enough about the mechanics of airflow and spacecraft to realize that this won't work. I would hope that you understand that further development of fan or parachute technology won't ever lead to this being a viable method for placing spacecraft into orbit.

The plasma propulsion concept is actually quite similar to this. There is a stationary spacecraft that generates the plasma (wind) and directs it at the mobile spacecraft which has a magnetic sail (parachute). The velocity of the plasma is much higher, but that actual motive principles are very much alike. However -- the fact that it needs a vacuum to work, and that the actual delta-v imparted by the plasma is very small means that it will never be a technology for putting spacraft into orbit.


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Post    Posted on: Mon Oct 25, 2004 2:48 pm
The vacuum is the reason why I mentioned suborbital spacecrafts that reach altitudes of several hundreds or thousands of kilometers - these regions a very clos to vacuum in contrary to low earth orbit.

I didn't think of the existing suborbital vehicles because they don't go high enough. But the main reason was that a particle beam into LEO or into the atmosphere will have an undesired impact on the atmosphere.



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Post    Posted on: Mon Oct 25, 2004 3:55 pm
mrmorris wrote:
The only reason a shuttlecock falls the way it does is because of the heavy weight at the tip and the perforations in the 'tail' generate a high-drag (like SS1's tail). The craft in question would have to have a similarly large and high-drag tail for this to work (and the tail itself would have to be heat-shielded, etc.). The traditional capsule shape is so nice because the teardrop shape is aerodynamically stable. Atmospheric friction will orient the capsule automagically with no control surfaces. Any control surface required for the craft adds mass that can't be used for payload.


I would hardly call the traditional capsule shape a teardrop - it is virtually flat on one end, but I think we're both aiming at the same thing here - an aerodynamically stable shape that automatically orients itself to the optimal re-entry angle.

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I disagree about the expense. The more automation that is available to the craft, the better. Ideally it should be able to handle *everything* without pilot input. What is ridiculous is the 99% automation of the shuttle. For example -- the entire shuttle landing is computer controlled except the landing gear. A human must push the button to extend the LG. This is silly. Likewise docking with the ISS. The Russians have had autonomous docking for years, and it's only now that NASA is developing it for the US with the DART program.


Admittedly I was only thinking about the original Gemini objectives - go up and down. For that, I believe in Gemini they increased the amount of pilot control since they complained about being space monkeys.

But for automated docking, then yes, that is definitely preferable to manual - although it again at this point it's all waiting for Bigelow to announce more details of the prize to see if this is actually needed.

On a note about the fairing for the Falcon V - I would say it is an important thing to consider, since the Falcon V is designed fundamentally to work with that fairing, and it would require a number of alterations to fit an alternative. Also, it is built to have decent aerodynamics for the ascent - you can't just stick the capsule on top of the second stage. An alternative fairing would therefore need to be made, at which point I would say it is simpler simply to make the capsule fit the fairing, rather than vice versa.

However, if the ordinary fairing is large enough anyway, then it is a moot point. (Keep in mind that to fit 5 to 7 people it is going to need to be considerably larger than the previous fairing on the Titan)

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Post    Posted on: Mon Oct 25, 2004 4:02 pm
this is a potentially interesting alternative. It works in the atmosphere, dramatically reduces the fuel to payload ratio, and is somewhat more efficient than chemical rockets. Better yet, actual experiments have been done to proove that it works in the lab.

Hopefully it will scale up.


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Post    Posted on: Mon Oct 25, 2004 8:58 pm
Sev wrote:
On a note about the fairing for the Falcon V - I would say it is an important thing to consider, since the Falcon V is designed fundamentally to work with that fairing, and it would require a number of alterations to fit an alternative. Also, it is built to have decent aerodynamics for the ascent - you can't just stick the capsule on top of the second stage.


The aerodynamics of the Gemini capsule are fairly good. After all -- they were designed to be placed on top of the Titan 2 (very similar lines to the Falcon V as I've said) without a fairing.

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However, if the ordinary fairing is large enough anyway, then it is a moot point. (Keep in mind that to fit 5 to 7 people it is going to need to be considerably larger than the previous fairing on the Titan)


It's not moot -- using the fairing adds mass and complexity. *None* of the manned projects of this type (Mercury, Gemini, Soyuz, Shenzhou) use fairings around the spacecraft.

The dimensions of the original Gemini capsule match very well with the fairing dimensions of the V.

Fairing: 3.05m x 6m
Gemini: 3.05 m x 5.7 m

As I mentioned on the space.com thread -- the wasted space in the original Gemini Equipment Module could easily be used by a modern version that eliminated this in favor of a larger Return Module/Crew cabin. I'm still working on equipment volume reductions and relocations, but I believe a modern version could carry six people without expanding the overall capsule size.


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Post    Posted on: Mon Oct 25, 2004 11:21 pm
Soyuz and Shenzou do use aerodynamic fairing.


Shenzhou on top of booster
Closeup
Shenzhou in orbit


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Post    Posted on: Tue Oct 26, 2004 12:15 am
mrmorris wrote:
As I mentioned on the space.com thread -- the wasted space in the original Gemini Equipment Module could easily be used by a modern version that eliminated this in favor of a larger Return Module/Crew cabin. I'm still working on equipment volume reductions and relocations, but I believe a modern version could carry six people without expanding the overall capsule size.


Out of interest, are you going to properly write up and accumulate the various studies you've made on this? You definitely seem to have taken to my little idea pretty avidly :)

Now, if only I knew a billionaire space nut...

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Post    Posted on: Tue Oct 26, 2004 1:46 am
Sev wrote:
Out of interest, are you going to properly write up and accumulate the various studies you've made on this?


I plan to. Whether I will or not... dunno. I've been saving my various calculations, technology substitutions, references, and so forth. It depends on how small I can make the 'HeckifIknow factor'. I've found reams of documentation on the Gemini -- including the original familiarization manuals given to the astronauts. However -- there's data I'll never be able to get, and despite the amount of time I spend researching space technologies -- it's not really my field. I'm a programmer, not an engineer.

I just ordered "Fundamental Techniques of Weight Estimating and Forcasting for Advanced Manned Spacecraft and Space Stations" by Willie Heineman, Jr.; NASA TN D-6349 from NASA. It was referenced on one of the sites where I found some specifics on Gemini volumes. I'm hoping it contains some missing details. If I can make a document that doesn't come across like a junior-high book report, I'll probably send a few copies around to the candidates for building such a beast: SpaceX, Scaled, SubOrbital, maybe Spacedev. Unfortunately -- I doubt any of them have the bandwidth to do it. It might well take a consortium.

And yes -- I do tend to get caught up when I involve myself in mental exercises. This one more than most, because I continue to be shocked at just how much potential there is. I'm positive that no one is seriously thinking about the possibility of a reusable 6-person spacecraft for a mass around (probably under) 4,500 kg.


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Post    Posted on: Tue Oct 26, 2004 7:22 am
Hello, Sev,

concerning the preference for automated docking to manual - recently the pilot of Soyuz had to dock manual because of too much speed. So allways there should be the possibility and the equipment to dock manual I think. It's required fopr safety that man can correct the computer(s) and the machine(s).

Hello, mrmorris,

acceleration by particle beam might be of use in connection to the space elevator too. If the elevator releases a spacecraft in vaccuum below geostationary altitude this spacecraft will have less than orbital velocity. So in this vacuum the spacecraft could be accelerated by the particle beam.



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Post    Posted on: Tue Oct 26, 2004 1:52 pm
mrmorris wrote:
And yes -- I do tend to get caught up when I involve myself in mental exercises. This one more than most, because I continue to be shocked at just how much potential there is. I'm positive that no one is seriously thinking about the possibility of a reusable 6-person spacecraft for a mass around (probably under) 4,500 kg.


Yep, a true-to-honest practical idea for how to get civilians to orbit for the same kind of funding that went into the SpaceShipOne project. Almost sounds too good to be true.

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Post    Posted on: Wed Oct 27, 2004 9:19 am
To return to a former - and already cleared - misunderstanding I caused for a short time:

Bigelow's Nautilus seems to be going to get a competitor - Branson is reported to be planning an orbital hotel in an article under www.xprizenews.org today. It's called Virgin Hotel. No information on dates - but he will have to pull tourists. It will be interesting what way he will do that - another prize? Given the five orderer five-passenger-spacecrafts a prize obviously isn't required. And there seems to be an error in the article - the five spacecrafts are called orbital two times at least.



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Post    Posted on: Wed Oct 27, 2004 11:22 am
Yes, but did he say how? No he didnt. Virgin cannot build space stations, someone got to build them and that someone may be Bigelow. So it may not be a competitior but a joint venture. Remember, Bigelow did say he was talking to someone for the other half of the Space Prize.


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Post    Posted on: Wed Oct 27, 2004 11:35 am
Do you suppose a deal - Branson gives 25 mio. $ and receives a second Nautilus?

Could that have impacts on the "Possible Craft"?



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Post    Posted on: Thu Oct 28, 2004 12:54 pm
Nothing beyond the specifications they draw up for the docking port.

However, I would say it is actually fairly likely for Branson to be considering Bigelow's stations for his hotel - it's the only thing that is remotely economically viable. If it works properly, he will have a way to build a station the size of the ISS for 1/100th the cost. He's rich, but not that rich.

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Post    Posted on: Thu Oct 28, 2004 1:22 pm
Ekkehard Augustin wrote:
Do you suppose a deal - Branson gives 25 mio. $ and receives a second Nautilus?


I agree with Sev that it is extremely unlikely that Virgin will try to develop space station technology on their own from scratch. Bigelow is the only (will be the only) commercial supplier of station habitation modules. Russia presumably would sell one to anyone with the money -- but Bigelow's inflatables will be larger and probably cheaper.

Understand though -- the Nautilus by itself is *not* a viable space station. It's is nothing more than a hab module (or laboratory/manufacturing space). At any rate -- it's primarily a big hollow space with some environmental systems imbedded. The assumption is that Bigelow will pruchase the equivalent of a Zvezda module from the Russians for command, communications, and propulsion capabilities.

The *cheapest* way for Branson to get hotel accomodations would be if Bigelow builds his commercial/industrial station, and Branson purchases one or more Nautilus modules to be tacked on to it (this avoids the costs of having to pay for the command & control portions of a separate station). However -- this might well conflict with the industrial aspects of the station, as people moving arouns will affect the microgravity aspects which is the primary value of orbital facilities.


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