"SpaceShipTwo could be single stage to SUBorbit"
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From: Marvin the Martian on 11 May 2010 19:29 On Tue, 11 May 2010 09:23:45 -0700, Robert Clark wrote: > On May 10, 2:47 pm, Robert Clark <rgregorycl...(a)yahoo.com> wrote: >> Interesting article here: < snip > > > If Virgin Galactic really is serious about this then I foresee > passenger orbital flights proceeding quite apace! a) You're replying to your own post? b) Space ship 2 goes about 4,200 km/hour * 1 hour/3600 sec = 1.2 km/s(1). LEO is about 9.3-10 km/s. Energy wise, the ratio of spaceship 2 to a LEO capable vehicle would be (1.2/9.3)^2 = 0.017. From there, it gets worse once you consider re-entry (need a way to dissipate 60x the energy), the rocket equation (the faster your delta V, the worse your rocket mass ratio) and so on. These plastic things are toys of the pompously named "Virgin Galactic" are meant to look impressive, but they are very far away from LEO. Very far. Their appeal is to give much undeserved astronauts wings to rich people who don't have anything better to do with their money. (1) http://en.wikipedia.org/wiki/SpaceShipTwo (2) http://en.wikipedia.org/wiki/Delta_v
From: Rick Jones on 11 May 2010 20:12 In sci.space.history Marvin the Martian <marvin(a)ontomars.org> wrote: > These plastic things are toys of the pompously named "Virgin > Galactic" are meant to look impressive, but they are very far away > from LEO. Very far. Their appeal is to give much undeserved > astronauts wings to rich people who don't have anything better to do > with their money. I take it you aren't all that impressed with barnstorming either? rick jones -- The glass is neither half-empty nor half-full. The glass has a leak. The real question is "Can it be patched?" these opinions are mine, all mine; HP might not want them anyway... :) feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...
From: Pat Flannery on 12 May 2010 04:41 On 5/11/2010 4:57 AM, Jeff Findley wrote: > > SpaceShipTwo is designed to fly high, not fast. You need both to make it > into orbit. One gets the feeling with SpaceShipTwo that if they could have kept the fight upwards subsonic, they would have gone for it. I still like that loopy idea to shoot the X-15 into orbit atop some sort of rocket booster, and have it reenter and crash into the Gulf of Mexico, with the pilot ejecting on the way down: http://www.astronautix.com/craft/x15b.htm I'm sure a lot of pilots would have lined up for that mission. "Pressure suit?" "Check." "Space helmet?" "Check". "Parachute?" "Check." "Shark repellent?" "Uh, now wait a minute." ;-) Pat
From: Pat Flannery on 12 May 2010 05:13 On 5/11/2010 12:17 PM, Bob Myers wrote: > On 5/11/2010 6:57 AM, Jeff Findley wrote: >> >> Actually, ignorant can be fixed. Stupid can't. In most cases, it's easy >> enough to explain that orbital velocity is so fast that you really do >> need a >> huge amount of fuel and oxidizer to get into orbit. The X-15 example >> helps >> somewhat too. The X-15 could fly high or fast, but could not do both >> on the >> same mission. And even the X-15's high speed flights only achieved a >> small >> fraction of orbital velocity. > > It would seem we need an explanation akin to something Douglas Adams > might have written - you know, comparable to "Space is big. You just won't > believe how vastly, hugely, mind- bogglingly big it is. I mean, you may > think > it's a long way down the road to the chemist's, but that's just peanuts > to space." > > However, I seem to recall that there was an idea, part of the old Air > Force "Man In Space, Soonest" proposals, that did involve basically > strapping on some additional boost to an X-15 and getting the thing into > orbit, no? Not sure how they were planning on dealing with the "getting > it back down" problem, either... > They did one X-15 test flight with a spray-on ablative TPS coating that was supposed to be easily cleaned off and replaced after the flight. What the pilots thought of this, as the aircraft was now pink*, has not been recorded. After the flight they found the ablative coating had cooked itself right on to the skin of the aircraft and was almost impossible to remove, so the concept was dropped. * I keep picturing it covered in pencil eraser rubber: http://www.dfrc.nasa.gov/gallery/photo/X-15/Small/ECN-1736.jpg Pat
From: Pat Flannery on 12 May 2010 05:24
On 5/11/2010 12:20 PM, Bob Myers wrote: > thumb its nose at gravity and come down as quickly or slowly as you want? > I'm even more disappointed that I can't yet go out and buy a Jetsons-type > Rosie the Robot or a flying car that folds up into a briefcase once I get to > work. But things are much more futuristic for cats, as Scott Lowther found on YouTube: http://www.youtube.com/watch?v=LQ-jv8g1YVI You just know that sooner or later the tail is going to go under the Roomba, and then the cat will never try that again. Here kittens find out about inertia: http://www.youtube.com/watch?v=GTxW3GWZ5hI&feature=related That must be some fun house - kittens, toddler, robot, dog. It's like some sort of bachelor's nightmare coming true. :-) Pat |