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Thermal Protection Scaled Composites
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Moon Mission Member ![]() ![]()
Joined: Tue Oct 05, 2004 5:38 pm
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My calculations say that with isp=250 you need a mass fraction of about 20 to get to orbit, neglecting gravity losses and air drag. With gravity and drag it is more like 40. That is in agreement with the other calculations above.
So given that SS1 has a mass fraction of only 3, have we decided that power should be back in the unsolved category? By the way, I was reviewing a video of Rutan's speech at the university of Texas (looking for that orbital statement) and in it he says that the navigation system in SS1 is capable of orbital operation. That puts us back to my first guess, where power and reentry are not solved and environment and navigation are. |
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Last edited by whonos on Thu Jun 07, 2007 7:16 pm, edited 1 time in total. |
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Joined: Thu Apr 14, 2005 6:47 pm
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Just adding in some of my own thoughts on this interesting discussion. I'm sure I remember Burt talking about the first orbital vehicle being a single person vehicle (probably in an internet article). Taking this into account shouldn't WK II be large enough as the carrier vehicle? As it already needs to carry 9 people above the height of SS1 plus two pilots and 7 passengers who will watch the launch. In this way the orbital vehicle would be what SS1 it to SS2, a technology demonstrator before a larger operational vehicle is built. Does this not mean that power is unlikely to be one of Burt's problems especially when using a more powerful engine.
When applied to a SS1 oriented vehicle can the CXV re-entry technology be easily applied? If I remember correctly SS1 has a very fast re-entry (in terms of time taken) is this an advantage or disadvantage with orbital re-entry. Just a final comment if Burt wants to create a seat of the pants orbital vehicle like SS1 then this could be one on the unsolved list. Making the vehicle safe enough to be flown hands on. Though I woud be suprised if the ping pong ball and string hasnt been modified or improved upon for SS2 |
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Joined: Tue Feb 10, 2004 2:56 am
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Consider the facts that A) once in orbit, you have to expend energy to deorbit, thus placing yourself in control of your reentry speed (unlike in suborbital flight, when you're simply falling, and your speed is determined by your zenith; and B) the orbital variant of SS1 will undoubtedly have a better glide path than the Brick-that-is-the-Space-Shuttle, and thus make a hands-on reentry much much safer.
broyale, welcome to the boards! Oh, and Peter, I just noticed that you have exactly 666 posts. A perfect time for your addition to the ranks of the Explorers, Sigurd's own Legion of Doom. ![]() _________________ American Institute of Aeronautics and Astronautics Daniel Guggenheim School of Aerospace Engineering In Memoriam... Apollo I - Soyuz I - Soyuz XI - STS-51L - STS-107 |
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Last edited by whonos on Thu Jun 07, 2007 7:16 pm, edited 1 time in total. |
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whonos wrote: broyale wrote: I'm sure I remember Burt talking about the first orbital vehicle being a single person vehicle (probably in an internet article). I've never heard that, do you have a link? |
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BINGO!
Quote: Speaking at a lecture organised by the Manx Festival of Aviation at the Royal Aeronautical Society in London, the aerospace designer detailed how such an orbital vehicle could be evolved from his existing three-man, suborbital 3,000kg (6,600lb) SpaceShipOne. The amount of spacecraft mass dedicated to fuel would be increased to achieve the greater altitude and speed required. "We'd have a small cramped cabin for the orbital flight and you'd be in it for a long time. You'd want to go to a hotel [because of that] and for orbital tourism you'd want an altitude of 130km," says Rutan. http://uplink.space.com/showflat.php?Ca ... o=0&fpart= http://www.tobiasbuckell.com/archives/001303.html <http://www.flightinternational.com/Articles/2004/08/17/186036/Rutan's+tourism+vision+includes+orbiting+hotel.html> |
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Joined: Thu Apr 14, 2005 6:47 pm
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The Flight International article was where I have read about Burt talking about a one person orbital craft, but thinking back I may also have seen footage of his lecture at the Royal Aeronautical Society broadcast on SKY's interactive news in the UK (They did a lot of extended coverage at this time on the interactive news service that I don't think they put on the regular broadcast and can be worthwhile checking out from time to time if your in the UK).
At the time I was also pretty suprised at the low altitude of the space station mentioned. Often on space forums people talk about 200km or greater for orbital spacecraft and stations. Wouldn't a 130km orbit improve the payload fraction mass of an orbital vehicle, even if only by a small amount and as a secondary bonus reduce any threat from orbital debris? |
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Last edited by whonos on Thu Jun 07, 2007 7:16 pm, edited 1 time in total. |
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BRoyale and CampbelP:
I do also remember something about a one-man orbital craft derived from SS1. I seem to remember he made a comment like that not long after SS1's success- I may well be wrong. The part about people not wanting to stay in orbit makes sense, relative to Rutan's businesslike character. The ship ride is cramped, so you'll want an actual destination, like an orbiting hotel. More captial that way. But if i was on a spacecraft, i would be happy regardless of the cramped accomodations. I'm also confused as to why he would consider such a low orbit for a station. Maybe he's thinking of some lighter-than-air, inflatable station? (Sound ridiculous?) |
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whonos wrote: A space station in a 130km orbit would decay rapidly and reenter the atmosphere within a few days. |
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Joined: Wed Dec 08, 2004 12:55 pm
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I read that with 130 km too, but what if he said (and was quoted wrong) or meant 130 miles (You'll never know those Americans with their miles, foot and inches preference
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Joined: Thu Jun 03, 2004 11:23 am
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The article had been posted somewhere at this board and I referred to it in another thread - but I can't find it currently. I used the thread or post as a source of information and got - among others the answer that the author of the article and the journalists had to be suspected to have done an error.
I myself explicitly thought of the possibility that there has occurred an error regarding the unit of distance - miles may have been exchanged by kilometers and Rutan originally and really may have been talking about 135 miles altitude instead of 135 km altitude. 135 miles are 216 km. I will continue to look for the threads. Dipl.-Volkswirt (bdvb) Augustin (Political Economist) EDIT: In between I found the article I used as well as the thread I referred to it: Article: www.xprizenews.org/index.php?p=418 Tuesday, 17th August, 2004 Thread: www.spacefellowship.com/Forum/viewtopic.php?t=851 I simply had recognized that Rutan had been speaking of an altitude the artilce had reported Nautilus will be installed at. This caused argumentation against the reported altitude of 130 km or 135 km for Nautilus. As a consequence I think Nautilus really will be installed at a significant higher orbit and that Rutan didn't intend really to go to an orbit of 135 km altitude. He might have intended to illustrate that he could achieve that orbit in principle - - to achieve it doesn't mean to keep it. |
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Joined: Thu Jun 03, 2004 11:23 am
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Hello, Klaus.Schmidt and others,
in the initial post of this thread you mentioned and asked for the two unsolved problems Rutan was speaking about. In the following posts this has been discussed a bit without result. In between Rutan has said something additional regarding breakthroughs - the article "Burt Rutan on Civilian Spaceflight, Breakthroughs, and Inside SpaceShipTwo" ( www.space.com/news/060811_rutan_interview.html ) he is quoted as follows: [quote]“My bottom line is that we have to have some kind of breakthroughs,†|
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Joined: Thu Jan 27, 2005 12:34 am
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SawSS1Jun21 wrote: Well, it's only called "life-support" on TV and in the movies... Maybe we'll get lucky and rpspeck will weigh in on this one, he's actually done a great deal of work on this exact problem. I know a few people who still call it life support (myself included). For emergency systems I believe this term is common. It isn’t difficult to evaporate water in zero G. One technique is through “Gore Tex†|
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