Guest Blackwater Posted July 17, 2007 Posted July 17, 2007 Odd Factoid revealed on BBC ... It's actually ILLEGAL for Brits to fly into space. http://www.bbc.co.uk/mediaselector/check/player/nol/newsid_6900000/newsid_6902400?redirect=6902415.stm&news=1&nbwm=1&bbram=1&nbram=1&bbwm=1 Apparently the government implemented the policy long ago, assuming it would prevent aerospace resources from being "wasted" on human flight. Quote
Guest Joe Strout Posted July 17, 2007 Posted July 17, 2007 In article <469cb0b4.4766375@news.east.earthlink.net>, bw@barrk.net (Blackwater) wrote: > It's actually ILLEGAL for Brits to fly into space. > ... > Apparently the government implemented the policy long ago, > assuming it would prevent aerospace resources from being > "wasted" on human flight. It'll be interesting to see them try to haul Branson off to jail after the maiden Virgin Galactic flight. -- "Polywell" fusion -- an approach to nuclear fusion that might actually work. Learn more and discuss via: <http://www.strout.net/info/science/polywell/> Quote
Guest Blackwater Posted July 17, 2007 Posted July 17, 2007 On Tue, 17 Jul 2007 09:27:45 -0600, Joe Strout <joe@strout.net> wrote: >In article <469cb0b4.4766375@news.east.earthlink.net>, > bw@barrk.net (Blackwater) wrote: > >> It's actually ILLEGAL for Brits to fly into space. >> ... >> Apparently the government implemented the policy long ago, >> assuming it would prevent aerospace resources from being >> "wasted" on human flight. > >It'll be interesting to see them try to haul Branson off to jail after >the maiden Virgin Galactic flight. He will probably be THE case ... the one that finally gets the law changed - and he damned well has the money, lawyers and status to do it. I saw something on TV the other day about one other brit trying to get to space. The last item was a semi-successful air drop of the one-man capsule (parachute didn't deploy until rather late). He had to go to Arizona USA to do the test, seems the british govt is being unreasonably picky about the use of local airspace. He's already launched some big ones from british soil. Branson will be the #1 private- sector brit in space ... but this other guy may be the next one along - albeit on a much smaller budget. Geez ... we REALLY need 'warp drive' or something. Reaction rockets are just TOO ... expensive, bulky, inefficient and dangerous. Got to knock at least an order of magnitude off the price to orbit. If you know any physics geniuses, buy 'em a few beers and then give 'em a mission before they're sober enough to change their minds. Quote
Guest Damon Hill Posted July 17, 2007 Posted July 17, 2007 bw@barrk.net (Blackwater) wrote in news:469d19a5.31631187@news.east.earthlink.net: > Geez ... we REALLY need 'warp drive' or something. > Reaction rockets are just TOO ... expensive, bulky, > inefficient and dangerous. Got to knock at least > an order of magnitude off the price to orbit. No solid theoretical basis for a warp drive. And what are you going to use for an energy source that doesn't weigh thousands of tons and bulks out in the vacuum of space far larger than your actual spaceship? Get used to rocket propulsion; it's going to be with us for quite a long time. --Damon, dumping a cold bucket of reality over your head Quote
Guest Joe Strout Posted July 17, 2007 Posted July 17, 2007 In article <Xns99708F6BB9313damon161attbicom@216.196.97.131>, Damon Hill <damon1SIX1@comcast.netnet> wrote: > Get used to rocket propulsion; it's going to be with us > for quite a long time. > > --Damon, dumping a cold bucket of reality over your head Absolutely. Now, chemical rockets are certainly not the be-all and end-all of rocket propulsion... nuclear rockets of some sort are probably the way to go, when we want to get around the solar system in a hurry. But they're still rockets. Best, - Joe -- "Polywell" fusion -- an approach to nuclear fusion that might actually work. Learn more and discuss via: <http://www.strout.net/info/science/polywell/> Quote
Guest Sylvia Else Posted July 17, 2007 Posted July 17, 2007 Blackwater wrote: > Odd Factoid revealed on BBC ... > > It's actually ILLEGAL for Brits to fly into space. > > http://www.bbc.co.uk/mediaselector/check/player/nol/newsid_6900000/newsid_6902400?redirect=6902415.stm&news=1&nbwm=1&bbram=1&nbram=1&bbwm=1 > > Apparently the government implemented the policy long ago, > assuming it would prevent aerospace resources from being > "wasted" on human flight. > Might even have been useful if it had ensured that aerospace resources in the UK were used to develop unmanned spaceflight. That's where the idea failed, of course. Sylvia. Quote
Guest Jeff Findley Posted July 18, 2007 Posted July 18, 2007 "Blackwater" <bw@barrk.net> wrote in message news:469d19a5.31631187@news.east.earthlink.net... > Geez ... we REALLY need 'warp drive' or something. > Reaction rockets are just TOO ... expensive, bulky, > inefficient and dangerous. Not really. What we really need is to stop throwing away the rockets after every flight. Maybe start with a fully reusable first stage then work up to a fully reusable upper stage, giving a fully reusable TSTO. > Got to knock at least > an order of magnitude off the price to orbit. If > you know any physics geniuses, buy 'em a few beers > and then give 'em a mission before they're sober > enough to change their minds. It ought to be possible to knock more than an order of magnitude off by focusing on making launch vehicles reusable and more efficient to turn around between flights. The technology is there, but to date, no one has managed to put those pieces of technology together into a vehicle that is truly economic to reuse. Jeff -- "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Tue, 17 Jul 2007 16:05:53 -0500, Damon Hill <damon1SIX1@comcast.netnet> wrote: >bw@barrk.net (Blackwater) wrote in >news:469d19a5.31631187@news.east.earthlink.net: > >> Geez ... we REALLY need 'warp drive' or something. >> Reaction rockets are just TOO ... expensive, bulky, >> inefficient and dangerous. Got to knock at least >> an order of magnitude off the price to orbit. > >No solid theoretical basis for a warp drive. Some ooey-gooey theory however ... but I recall it requires "negative energy" to work. They may get further (hee hee) with quantum teleportation. >And what are you going to use for an energy source that >doesn't weigh thousands of tons and bulks out in the >vacuum of space far larger than your actual spaceship? Who sez 'alterantive' propulsion methods NEED vast quantites of energy ? Might run on a 9v battery :-) I wonder how to make inertia go away ... ? >Get used to rocket propulsion; it's going to be with us >for quite a long time. Probably - but it DOES suck. When it finally gets to be TOO much of a bother, well, laziness IS the mother of invention. Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 08:33:47 -0400, "Jeff Findley" <jeff.findley@ugs.nojunk.com> wrote: > >"Blackwater" <bw@barrk.net> wrote in message >news:469d19a5.31631187@news.east.earthlink.net... >> Geez ... we REALLY need 'warp drive' or something. >> Reaction rockets are just TOO ... expensive, bulky, >> inefficient and dangerous. > >Not really. Really ? Go build a big rocket and see what it does to your bank balance. >What we really need is to stop throwing away the rockets after >every flight. Sounds great - but it never seems to work out in practice. The stresses of operation and plunging back again combined with the need for lightweight components ... well ... I wouldn't want to ride a re-used booster. > Maybe start with a fully reusable first stage then work up to >a fully reusable upper stage, giving a fully reusable TSTO. Bert Rutan may have come up with a viable fix - use some kind of aircraft as the "1st stage". Nowdays it can be fully robotic, autopiloted. A big wing with engines optimized for high altitudes and you can cut the first 60,000 feet off your trip. Use a simple SRB as the '2nd stage'. Save the expensive stuff for the final orbital-insertion stage. It would be a help ... but it wouldn't add-up to anywhere near the necessary order-of-magnitude price reduction needed to properly commercialize space. Scramjet-powered orbital air/spacecraft - someday, maybe ... >> Got to knock at least >> an order of magnitude off the price to orbit. If >> you know any physics geniuses, buy 'em a few beers >> and then give 'em a mission before they're sober >> enough to change their minds. > >It ought to be possible to knock more than an order of magnitude off by >focusing on making launch vehicles reusable and more efficient to turn >around between flights. I don't believe it. It would require a DRASTIC simplification of the design, so fewer things could go wrong and fixes would be quick cheap and easy. Nobody seems able to do that, not America, not Russia, not China, not Japan, not France. If anything, designs have just become MORE complex and fragile. As for "efficiency" ... rocket efficiency isn't going to increase much. It's the physics. Recovery/repair/reuse efficiency COULD improve considerably, but then we still need robust and simplistic designs to make that possible. >The technology is there, but to date, no one has >managed to put those pieces of technology together into a vehicle that is >truly economic to reuse. You act as if they're lagging behind intentionally. The USA might, "porkbarrel politics", but not any of the others. I fear the real exploitation of space will ONLY become possible when some drastically new propulsion technology appears. I say 'warp drive', but that probably won't work. Higher dimensions, inertia-reduction, funky quantum tricks ... we'd better find SOMETHING or we're STUCK on this increasingly small and crowded ball of rock. "Space" is simply uneconomic and looks to remain uneconomic. Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 09:39:14 +1000, Sylvia Else <sylvia@not.at.this.address> wrote: >Blackwater wrote: >> Odd Factoid revealed on BBC ... >> >> It's actually ILLEGAL for Brits to fly into space. >> >> http://www.bbc.co.uk/mediaselector/check/player/nol/newsid_6900000/newsid_6902400?redirect=6902415.stm&news=1&nbwm=1&bbram=1&nbram=1&bbwm=1 >> >> Apparently the government implemented the policy long ago, >> assuming it would prevent aerospace resources from being >> "wasted" on human flight. >> > >Might even have been useful if it had ensured that aerospace resources >in the UK were used to develop unmanned spaceflight. That's where the >idea failed, of course. Yep. Of course I'm sure the money went into military & civilian AIRCRAFT development, along with a certain amount of 'space' related stuff - radiotelescopes and such. A pity. There turned out to be quite a lot of money in communications, navigation and remote-sensing satellites. Britain COULD have been right there alongside the Americans and Russians. May be too late now ... looks as if China and India are taking over the launch business. I suppose Brits could build the satellites themselves ... seems like all the best electronics magazines nowdays are British :-) (Americans have become jaded, lost the old "build it yourself" spirit when it comes to gadgets. If it's not on the shelf at K-Mart they're not interested. Aside from a small niche - the 'Circuit Cellar' chip junkies and robotics hobbyists - American 'home brew' electronics seem dead. Many 'Radio Shack' stores hardly carry a single chip or resistor anymore, an impediment to the next generation) Quote
Guest Jeff Findley Posted July 18, 2007 Posted July 18, 2007 "Blackwater" <bw@barrk.net> wrote in message news:469e0eb6.6752038@news.east.earthlink.net... > On Wed, 18 Jul 2007 08:33:47 -0400, "Jeff Findley" > <jeff.findley@ugs.nojunk.com> wrote: > >> >>"Blackwater" <bw@barrk.net> wrote in message >>news:469d19a5.31631187@news.east.earthlink.net... >>> Geez ... we REALLY need 'warp drive' or something. >>> Reaction rockets are just TOO ... expensive, bulky, >>> inefficient and dangerous. >> >>Not really. > > Really ? > > Go build a big rocket and see what it does > to your bank balance. > >>What we really need is to stop throwing away the rockets after >>every flight. > > Sounds great - but it never seems to work out in practice. > The stresses of operation and plunging back again combined > with the need for lightweight components ... well ... I > wouldn't want to ride a re-used booster. > >> Maybe start with a fully reusable first stage then work up to >>a fully reusable upper stage, giving a fully reusable TSTO. > > Bert Rutan may have come up with a viable fix - use some > kind of aircraft as the "1st stage". Nowdays it can be fully > robotic, autopiloted. A big wing with engines optimized for > high altitudes and you can cut the first 60,000 feet off > your trip. > > Use a simple SRB as the '2nd stage'. Save the expensive stuff > for the final orbital-insertion stage. > > It would be a help ... but it wouldn't add-up to anywhere > near the necessary order-of-magnitude price reduction needed > to properly commercialize space. Scramjet-powered orbital > air/spacecraft - someday, maybe ... > >>> Got to knock at least >>> an order of magnitude off the price to orbit. If >>> you know any physics geniuses, buy 'em a few beers >>> and then give 'em a mission before they're sober >>> enough to change their minds. >> >>It ought to be possible to knock more than an order of magnitude off by >>focusing on making launch vehicles reusable and more efficient to turn >>around between flights. > > I don't believe it. Why not? Airliners aren't expendable. It's part of the reason we can justify the extreme costs to develop, build, and fly super efficient high bypass turbofan engines for them. The other big reason is the huge demand for passenger air travel. > It would require a DRASTIC simplification of the design, so > fewer things could go wrong and fixes would be quick cheap > and easy. Nobody seems able to do that, not America, not > Russia, not China, not Japan, not France. If anything, > designs have just become MORE complex and fragile. I doubt it. In many ways a reusable is far more complex than an expendable. You justify this complexity, and cost, by flying it more than once. > As for "efficiency" ... rocket efficiency isn't going to > increase much. It's the physics. Recovery/repair/reuse > efficiency COULD improve considerably, but then we still > need robust and simplistic designs to make that possible. Time for a reality check. The cost of fuel and oxidizer for a launch vehicle is absolutely tiny compared to overall launch costs. I personally like LOX/kerosene since both are widely available and the kerosene is pretty dense. The Saturn V first stage burned something like 200,000 gallons of "rocket grade" kerosene (RP-1). If you're paying $5 per gallon for your kerosene, that's only $1 million dollars per launch. That's a pitiful fraction of the overall costs for an expendable Saturn V launch. And LOX is extremely cheap, litterally pennies per pound, in industrial quantities since air is the raw material you start with. One astronautix.com page says NASA was paying $0.08 per kg in the 1980's for LOX. Clearly, it's not physics that dictates the cost since the fuel and oxidizer needed are relatively cheap. >>The technology is there, but to date, no one has >>managed to put those pieces of technology together into a vehicle that is >>truly economic to reuse. > > You act as if they're lagging behind intentionally. The USA > might, "porkbarrel politics", but not any of the others. > > I fear the real exploitation of space will ONLY become possible > when some drastically new propulsion technology appears. I say > 'warp drive', but that probably won't work. Higher dimensions, > inertia-reduction, funky quantum tricks ... we'd better find > SOMETHING or we're STUCK on this increasingly small and crowded > ball of rock. "Space" is simply uneconomic and looks to remain > uneconomic. One of the biggest problems is that it's hard to get funding to develop a new reusable launch vehicle. There are many reasons for this. One of the biggest in the US is that every time NASA attempts building a reusable, they screw it up. The shuttle was the first generation reusable, but it's clear that so many compromises were made to lower development costs that operational costs suffered greatly. Next you've got the X-33 boondoggle. NASA picked the most technically challenging design which simultaneously gave the contract to a company who had a vested interest in the business as usual approach of using ELV's. It was a recipe for disaster from the start. For X-33 especially, it wasn't lack of technology which doomed the project to failure. Unfortunately for potential start-ups, it's a bit of a problem in that they have to explain why NASA failed and why NASA's official statement that they "lacked the technology" wasn't the real reason that X-33 failed. The other really huge problem is that of supply and demand. Right now launch costs are high and demand is correspondingly low. Without the introduction of some new market, it doesn't seem like there is enough demand out there to justify the investment in a completely reusable launch vehicle. It's cheaper to develop a new expendable than a new reusable, so you have to justify those increased development costs by showing that you can make that money back over time. That's hard to do when there are so few examples of reusable launch vehicles. In a sense, a reusable launch vehicle is a huge leap when it comes to launch vehicles. It's so huge of a leap that large companies have been very reluctant to pony up the money to develop one on their own, and many of the small startups are still finding it difficult to get investors to kick in enough funding. To say that we should skip development of reusable rocket powered launch vehicles and go straight to warp drive (or something) is laughable. Such a thing is far worse than what NASA did, which was to skip all the prototypes (except for subsonic landing tests) and go straight to a "reusable" space shuttle that had to work right the first time from launch to landing. Jeff -- "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 10:01:34 -0400, "Jeff Findley" <jeff.findley@ugs.nojunk.com> wrote: > >"Blackwater" <bw@barrk.net> wrote in message >news:469e0eb6.6752038@news.east.earthlink.net... >> On Wed, 18 Jul 2007 08:33:47 -0400, "Jeff Findley" >> <jeff.findley@ugs.nojunk.com> wrote: >> >>> >>>"Blackwater" <bw@barrk.net> wrote in message >>>news:469d19a5.31631187@news.east.earthlink.net... >>>> Geez ... we REALLY need 'warp drive' or something. >>>> Reaction rockets are just TOO ... expensive, bulky, >>>> inefficient and dangerous. >>> >>>Not really. >> >> Really ? >> >> Go build a big rocket and see what it does >> to your bank balance. >> >>>What we really need is to stop throwing away the rockets after >>>every flight. >> >> Sounds great - but it never seems to work out in practice. >> The stresses of operation and plunging back again combined >> with the need for lightweight components ... well ... I >> wouldn't want to ride a re-used booster. >> >>> Maybe start with a fully reusable first stage then work up to >>>a fully reusable upper stage, giving a fully reusable TSTO. >> >> Bert Rutan may have come up with a viable fix - use some >> kind of aircraft as the "1st stage". Nowdays it can be fully >> robotic, autopiloted. A big wing with engines optimized for >> high altitudes and you can cut the first 60,000 feet off >> your trip. >> >> Use a simple SRB as the '2nd stage'. Save the expensive stuff >> for the final orbital-insertion stage. >> >> It would be a help ... but it wouldn't add-up to anywhere >> near the necessary order-of-magnitude price reduction needed >> to properly commercialize space. Scramjet-powered orbital >> air/spacecraft - someday, maybe ... >> >>>> Got to knock at least >>>> an order of magnitude off the price to orbit. If >>>> you know any physics geniuses, buy 'em a few beers >>>> and then give 'em a mission before they're sober >>>> enough to change their minds. >>> >>>It ought to be possible to knock more than an order of magnitude off by >>>focusing on making launch vehicles reusable and more efficient to turn >>>around between flights. >> >> I don't believe it. > >Why not? Airliners aren't expendable. NOT the same animal, NOT the same jungle. Spacecraft have to be built much lighter, more fragile, and then are sujected to extreme accelerations, vibrations, thermal distortions and corrosive chemicals. >It's part of the reason we can >justify the extreme costs to develop, build, and fly super efficient high >bypass turbofan engines for them. The other big reason is the huge demand >for passenger air travel. Actually, the passengers fly for "free" - it's the CARGO under their feet that generates the profits. >> It would require a DRASTIC simplification of the design, so >> fewer things could go wrong and fixes would be quick cheap >> and easy. Nobody seems able to do that, not America, not >> Russia, not China, not Japan, not France. If anything, >> designs have just become MORE complex and fragile. > >I doubt it. In many ways a reusable is far more complex than an expendable. >You justify this complexity, and cost, by flying it more than once. But the complexity works AGAINST you trying to re-use the component. Every component interacts with many others, it quickly gets out of hand. Why do you think there are so often last-second delays launching shuttles ? ALL those little parts have to be tweaked, for a few minutes, into harmonious operation. They can BARELY do it. Actually, they CAN'T do it ... they just fudge on the safety parameters and launch anyway. >> As for "efficiency" ... rocket efficiency isn't going to >> increase much. It's the physics. Recovery/repair/reuse >> efficiency COULD improve considerably, but then we still >> need robust and simplistic designs to make that possible. > >Time for a reality check. Been there, checked-in. Waiting for you to show up :-) USA porkbarrel politics work against efficiency and simplicity - but this isn't the case in the other spacefaring countries. If France or Russia COULD do it all that more cheaply and better they WOULD have. The observable reality says "This is as good as it gets". >The cost of fuel and oxidizer for a launch vehicle is absolutely tiny >compared to overall launch costs. I personally like LOX/kerosene since both >are widely available and the kerosene is pretty dense. Agreed and agreed ... it's not the fuel (even though LOX requires a lot of energy to make and a lot of care to handle). It's the MACHINE the fuel goes into. It's the highly-trained PEOPLE required to make sure everything's right. It's the huge FACILITIES and INFRASTRUCTURE required to support everything. If these were private ventures you'd also have to add INSURANCE to the mix. Rockets are still essentially custom-made one-off machines. There's no assembly line, no grand template, no army of industrial robots, no real "standard components". This makes them incredibly expensive. Dealing with every issue the engineers know about or can imagine makes them insanely complex and expensive. This can't change unless designs are somehow simplified and sufficient VOLUMES of a 'standard rocket' are ordered so that assembly-line economics CAN begin to have an effect. >The Saturn V first >stage burned something like 200,000 gallons of "rocket grade" kerosene >(RP-1). If you're paying $5 per gallon for your kerosene, that's only $1 >million dollars per launch. That's a pitiful fraction of the overall costs >for an expendable Saturn V launch. And LOX is extremely cheap, litterally >pennies per pound, in industrial quantities since air is the raw material >you start with. One astronautix.com page says NASA was paying $0.08 per kg >in the 1980's for LOX. > >Clearly, it's not physics that dictates the cost since the fuel and oxidizer >needed are relatively cheap. The physics I was speaking of relate to how much bang you can get out of a rocket engine of a given size. It's a function of ignition-chamber pressure, subsequent gas expansion and velocity plus the weight of the components. X-energy IN, Y-energy translated into thrust. Hasn'tchanged much since the 60s. It defines the vehicle/cargo weight ratio. Some of the newer materials - carbon nanotube composites for example - MAY allow chamber pressures to rise somewhat while also reducing the weight of the chamber/nozzle assembly. If so, engine efficiency will improve - somewhat. >>>The technology is there, but to date, no one has >>>managed to put those pieces of technology together into a vehicle that is >>>truly economic to reuse. >> >> You act as if they're lagging behind intentionally. The USA >> might, "porkbarrel politics", but not any of the others. >> >> I fear the real exploitation of space will ONLY become possible >> when some drastically new propulsion technology appears. I say >> 'warp drive', but that probably won't work. Higher dimensions, >> inertia-reduction, funky quantum tricks ... we'd better find >> SOMETHING or we're STUCK on this increasingly small and crowded >> ball of rock. "Space" is simply uneconomic and looks to remain >> uneconomic. > >One of the biggest problems is that it's hard to get funding to develop a >new reusable launch vehicle. There are many reasons for this. Reasons 'A'-'Z' ... REALLY damned expensive !!! >One of the biggest in the US is that every time NASA attempts building a >reusable, they screw it up. The shuttle was the first generation reusable, >but it's clear that so many compromises were made to lower development costs >that operational costs suffered greatly. Americans in particular, especially when political committees get involved, always lean towards "multi-mission" designs. We see it in American military aircraft AND in spacecraft. They want one machine to do it all ... and wind up drastically increasing size, cost and complexity while reducing reliability. In part it's "porkbarrel politics", in part it just seems to be a cultural bias. The new generation of US spacecraft show SOME refinements to the 'one size fits all' mentality. They're meant to be fairly "modular" so you can pick the booster/upper/capsule combo that best fits the particular mission. These 'modules' are also more 'standard', increasing production efficiency. Not ENOUGH of course, but at least thinking has improved a bit. >Next you've got the X-33>boondoggle. Let us not speak of it ... >NASA picked the most technically challenging design which >simultaneously gave the contract to a company who had a vested interest in >the business as usual approach of using ELV's. It was a recipe for disaster >from the start. For X-33 especially, it wasn't lack of technology which >doomed the project to failure. Unfortunately for potential start-ups, it's >a bit of a problem in that they have to explain why NASA failed and why >NASA's official statement that they "lacked the technology" wasn't the real >reason that X-33 failed. It was the butt-covering "reason" ... and still accepted as gospel since a lot of the cover-ees are still in NASA or govt. >The other really huge problem is that of supply and demand. Right now >launch costs are high and demand is correspondingly low. Without the >introduction of some new market, it doesn't seem like there is enough demand >out there to justify the investment in a completely reusable launch vehicle. >It's cheaper to develop a new expendable than a new reusable, so you have to >justify those increased development costs by showing that you can make that >money back over time. That's hard to do when there are so few examples of >reusable launch vehicles. I prefer a completely DISPOSABLE vehicle. Build it to make exactly ONE flight - build it simple. Designing for re-use adds mass and complexity. It also locks you into the one design. You've made your 'investment' and now you're stuck. The easiest 'disposable' route for spacecraft is to make maximum use of SRBs. Alone, or combined with LFRs so a range of thrust adjustment is possible, they're really a good way to add oomph without adding much cost. Not much more than a tube packed with 'powder'. >In a sense, a reusable launch vehicle is a huge leap when it comes to launch >vehicles. It's so huge of a leap that large companies have been very >reluctant to pony up the money to develop one on their own, and many of the >small startups are still finding it difficult to get investors to kick in >enough funding. > >To say that we should skip development of reusable rocket powered launch >vehicles and go straight to warp drive (or something) is laughable. I'm saying that we NEED 'warp drive' or whatever to really make space something viable, affordable and safe (enough). I really don't think we're going to accomplish that with conventional rockets - reusable or not. Of course we're STUCK with them, for now, but we're likewise stuck with all their problems and limitations. Someday somebody will come up with a propulsion system better than spurting hot gas out the rear. A certain amount of money SHOULD be allocated to fund the kinds of theorists interested in such things. As the work will be 99.9% mental, it won't be expensive - just enough to keep a dozen or two PhDs from starving. >Such a >thing is far worse than what NASA did, which was to skip all the prototypes >(except for subsonic landing tests) and go straight to a "reusable" space >shuttle that had to work right the first time from launch to landing. NASA is 25% science and 75% politics. Expect a similar ratio of good/bad decisions from them. Quote
Guest Rand Simberg Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 15:58:16 GMT, in a place far, far away, bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such a way as to indicate that: >>I doubt it. In many ways a reusable is far more complex than an expendable. >>You justify this complexity, and cost, by flying it more than once. > > But the complexity works AGAINST you trying to re-use the > component. Every component interacts with many others, it > quickly gets out of hand. Why do you think there are so > often last-second delays launching shuttles ? ALL those > little parts have to be tweaked, for a few minutes, into > harmonious operation. They can BARELY do it. Actually, they > CAN'T do it ... they just fudge on the safety parameters > and launch anyway. It is a logical fallacy to draw general conclusions from a single data point, even if it's the only one you have. The Shuttle doesn't tell us much useful about reusable vehicles. Particularly since much of it isn't even reusable. Quote
Guest Bill Bonde ( 'Hi ho' ) Posted July 18, 2007 Posted July 18, 2007 Blackwater wrote: > > On Tue, 17 Jul 2007 09:27:45 -0600, Joe Strout <joe@strout.net> wrote: > > >In article <469cb0b4.4766375@news.east.earthlink.net>, > > bw@barrk.net (Blackwater) wrote: > > > >> It's actually ILLEGAL for Brits to fly into space. > >> ... > >> Apparently the government implemented the policy long ago, > >> assuming it would prevent aerospace resources from being > >> "wasted" on human flight. > > > >It'll be interesting to see them try to haul Branson off to jail after > >the maiden Virgin Galactic flight. > > He will probably be THE case ... the one that > finally gets the law changed - and he damned > well has the money, lawyers and status to do it. > I suspect anyone who has the money to get into space would be enough to get such a law changed. > > Geez ... we REALLY need 'warp drive' or something. > Reaction rockets are just TOO ... expensive, bulky, > inefficient and dangerous. Got to knock at least > an order of magnitude off the price to orbit. If > you know any physics geniuses, buy 'em a few beers > and then give 'em a mission before they're sober > enough to change their minds. > We probably shouldn't waste resources on warp drives. Let's make a law. -- "I hate you and I despise you! Now give me back my tail.", Marilyn Monroe, "Bus Stop" Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 16:23:10 GMT, simberg.interglobal@org.trash (Rand Simberg) wrote: >On Wed, 18 Jul 2007 15:58:16 GMT, in a place far, far away, >bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such >a way as to indicate that: > > >>>I doubt it. In many ways a reusable is far more complex than an expendable. >>>You justify this complexity, and cost, by flying it more than once. >> >> But the complexity works AGAINST you trying to re-use the >> component. Every component interacts with many others, it >> quickly gets out of hand. Why do you think there are so >> often last-second delays launching shuttles ? ALL those >> little parts have to be tweaked, for a few minutes, into >> harmonious operation. They can BARELY do it. Actually, they >> CAN'T do it ... they just fudge on the safety parameters >> and launch anyway. > >It is a logical fallacy to draw general conclusions from a single data >point, even if it's the only one you have. The Shuttle doesn't tell >us much useful about reusable vehicles. Particularly since much of it >isn't even reusable. Show me how to build a reusuable vehicle that ISN'T burdened-down by it's own complexity and requirements for reusability and I'll consider modifying my assessment. Quote
Guest Rand Simberg Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 17:35:03 GMT, in a place far, far away, bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such a way as to indicate that: >On Wed, 18 Jul 2007 16:23:10 GMT, simberg.interglobal@org.trash (Rand >Simberg) wrote: > >>On Wed, 18 Jul 2007 15:58:16 GMT, in a place far, far away, >>bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such >>a way as to indicate that: >> >> >>>>I doubt it. In many ways a reusable is far more complex than an expendable. >>>>You justify this complexity, and cost, by flying it more than once. >>> >>> But the complexity works AGAINST you trying to re-use the >>> component. Every component interacts with many others, it >>> quickly gets out of hand. Why do you think there are so >>> often last-second delays launching shuttles ? ALL those >>> little parts have to be tweaked, for a few minutes, into >>> harmonious operation. They can BARELY do it. Actually, they >>> CAN'T do it ... they just fudge on the safety parameters >>> and launch anyway. >> >>It is a logical fallacy to draw general conclusions from a single data >>point, even if it's the only one you have. The Shuttle doesn't tell >>us much useful about reusable vehicles. Particularly since much of it >>isn't even reusable. > > Show me how to build a reusuable vehicle that ISN'T > burdened-down by it's own complexity and requirements > for reusability and I'll consider modifying my assessment. There is nothing wrong with complexity. A modern airliner is quite complex. The primary difference between an air transport and a space transport is the much higher fllight rate of the former. The challenge of building a reusable launch vehicle isn't a technical one--it's a fiscal one. One has to raise the money to do so. No one, to date, has done so, but it will likely happen, now that new markets are being pursued, and new investment coming in. Kistler, in fact, may yet fly, if they can get through the next financing round. Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 10:23:45 -0700, "Bill Bonde ( 'Hi ho' )" <tributyltinpaint@yahoo.co.uk> wrote: > > >Blackwater wrote: >> >> On Tue, 17 Jul 2007 09:27:45 -0600, Joe Strout <joe@strout.net> wrote: >> >> >In article <469cb0b4.4766375@news.east.earthlink.net>, >> > bw@barrk.net (Blackwater) wrote: >> > >> >> It's actually ILLEGAL for Brits to fly into space. >> >> ... >> >> Apparently the government implemented the policy long ago, >> >> assuming it would prevent aerospace resources from being >> >> "wasted" on human flight. >> > >> >It'll be interesting to see them try to haul Branson off to jail after >> >the maiden Virgin Galactic flight. >> >> He will probably be THE case ... the one that >> finally gets the law changed - and he damned >> well has the money, lawyers and status to do it. >> >I suspect anyone who has the money to get into space would be enough to >get such a law changed. Branson has two other things going for him - his charisma and general British Pride in a local boy who's done so well. A snobby SOB who inhereited daddys money wouldn't have it so easy. Branson is more than a businessman, he's a celebrity and hero-figure. (yes, 'idiot-figure' to those who distain dangerous adventures, but those are a minority) >> Geez ... we REALLY need 'warp drive' or something. >> Reaction rockets are just TOO ... expensive, bulky, >> inefficient and dangerous. Got to knock at least >> an order of magnitude off the price to orbit. If >> you know any physics geniuses, buy 'em a few beers >> and then give 'em a mission before they're sober >> enough to change their minds. >> >We probably shouldn't waste resources on warp drives. Let's make a law. We probably shouldn't waste resources on "flying machines" or 'electricity'. Let's make it a law. OK ? Fortunately, 'warp drive' or whatever isn't for back-yard mechanics. It's for math geniuses. They aren't very expensive to maintain - cockroach-ridden apartment and a steady supply of coffee. Put off repainting the VAB building at Kennedy for a year and you could fund 100 of these guys for decades. Only when they've really GOT something need any significant hardware investments be made. Quote
Guest Rand Simberg Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 17:44:48 GMT, in a place far, far away, bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such a way as to indicate that: > Fortunately, 'warp drive' or whatever isn't for back-yard > mechanics. It's for math geniuses. They aren't very expensive > to maintain - cockroach-ridden apartment and a steady supply > of coffee. Put off repainting the VAB building at Kennedy for > a year and you could fund 100 of these guys for decades. Yes, with a significant probability that they'll never come up with a warp drive. On the other hand, we do know how to build affordable space transports, with no new physics required. Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 17:53:21 GMT, simberg.interglobal@org.trash (Rand Simberg) wrote: >On Wed, 18 Jul 2007 17:44:48 GMT, in a place far, far away, >bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such >a way as to indicate that: > > >> Fortunately, 'warp drive' or whatever isn't for back-yard >> mechanics. It's for math geniuses. They aren't very expensive >> to maintain - cockroach-ridden apartment and a steady supply >> of coffee. Put off repainting the VAB building at Kennedy for >> a year and you could fund 100 of these guys for decades. > >Yes, with a significant probability that they'll never come up with a >warp drive. Doesn't HAVE to be 'warp drive' per-se you know ... A 'teleportation' trick would serve just as well. A way to locally nullify gravity would be great. A way to make 99.9% of an objects mass/inertia seem to vanish would be great too. In short, there are many approaches to the problem ... we just need a lot of really smart people WORKING on them. Five years, fifty years ... irrelevant. The benifits when a work-around IS found will pay off a billionfold minimum. >On the other hand, we do know how to build affordable >space transports, with no new physics required. Well, so long as you don't mind one in fifty blowing itself to smithereens ... Quote
Guest Rand Simberg Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 18:13:58 GMT, in a place far, far away, bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such a way as to indicate that: >>On the other hand, we do know how to build affordable >>space transports, with no new physics required. > > Well, so long as you don't mind one in fifty > blowing itself to smithereens ... I do in fact mind that. Assuming I were in charge, I would design and operate it in such a way that it wouldn't happen, since there's no reason that it has to. In fact, a vehicle that "blows itself to smithereens" with that kind of regularity would in fact not be affordable. Quote
Guest Jeff Findley Posted July 18, 2007 Posted July 18, 2007 "Blackwater" <bw@barrk.net> wrote in message news:469e35f5.7727078@news.east.earthlink.net... > On Wed, 18 Jul 2007 10:01:34 -0400, "Jeff Findley" > <jeff.findley@ugs.nojunk.com> wrote: > >> >>"Blackwater" <bw@barrk.net> wrote in message >>news:469e0eb6.6752038@news.east.earthlink.net... >>> On Wed, 18 Jul 2007 08:33:47 -0400, "Jeff Findley" >>> <jeff.findley@ugs.nojunk.com> wrote: >>> >>>> >>>>"Blackwater" <bw@barrk.net> wrote in message >>>>news:469d19a5.31631187@news.east.earthlink.net... >>>>> Geez ... we REALLY need 'warp drive' or something. >>>>> Reaction rockets are just TOO ... expensive, bulky, >>>>> inefficient and dangerous. >>>> >>>>Not really. >>> >>> Really ? >>> >>> Go build a big rocket and see what it does >>> to your bank balance. >>> >>>>What we really need is to stop throwing away the rockets after >>>>every flight. >>> >>> Sounds great - but it never seems to work out in practice. >>> The stresses of operation and plunging back again combined >>> with the need for lightweight components ... well ... I >>> wouldn't want to ride a re-used booster. >>> >>>> Maybe start with a fully reusable first stage then work up to >>>>a fully reusable upper stage, giving a fully reusable TSTO. >>> >>> Bert Rutan may have come up with a viable fix - use some >>> kind of aircraft as the "1st stage". Nowdays it can be fully >>> robotic, autopiloted. A big wing with engines optimized for >>> high altitudes and you can cut the first 60,000 feet off >>> your trip. >>> >>> Use a simple SRB as the '2nd stage'. Save the expensive stuff >>> for the final orbital-insertion stage. >>> >>> It would be a help ... but it wouldn't add-up to anywhere >>> near the necessary order-of-magnitude price reduction needed >>> to properly commercialize space. Scramjet-powered orbital >>> air/spacecraft - someday, maybe ... >>> >>>>> Got to knock at least >>>>> an order of magnitude off the price to orbit. If >>>>> you know any physics geniuses, buy 'em a few beers >>>>> and then give 'em a mission before they're sober >>>>> enough to change their minds. >>>> >>>>It ought to be possible to knock more than an order of magnitude off by >>>>focusing on making launch vehicles reusable and more efficient to turn >>>>around between flights. >>> >>> I don't believe it. >> >>Why not? Airliners aren't expendable. > > NOT the same animal, NOT the same jungle. Spacecraft have > to be built much lighter, more fragile, and then are > sujected to extreme accelerations, vibrations, thermal > distortions and corrosive chemicals. So what. Just because they're not exactly the same animal doesn't mean that there isn't room for improvement with rockets. Throwing away your engines on each and every flight is more than a bit silly if your long term goal is to reduce reoccuring launch costs. >>It's part of the reason we can >>justify the extreme costs to develop, build, and fly super efficient high >>bypass turbofan engines for them. The other big reason is the huge demand >>for passenger air travel. > > Actually, the passengers fly for "free" - it's the CARGO > under their feet that generates the profits. Then lets add the huge demand for fast cargo transport as a reason the jet engine companies keep eeking out more performance for less fuel out of next generation engines. >>> It would require a DRASTIC simplification of the design, so >>> fewer things could go wrong and fixes would be quick cheap >>> and easy. Nobody seems able to do that, not America, not >>> Russia, not China, not Japan, not France. If anything, >>> designs have just become MORE complex and fragile. >> >>I doubt it. In many ways a reusable is far more complex than an >>expendable. >>You justify this complexity, and cost, by flying it more than once. > > But the complexity works AGAINST you trying to re-use the > component. Every component interacts with many others, it > quickly gets out of hand. Why do you think there are so > often last-second delays launching shuttles ? ALL those > little parts have to be tweaked, for a few minutes, into > harmonious operation. They can BARELY do it. Actually, they > CAN'T do it ... they just fudge on the safety parameters > and launch anyway. Why use the shuttle as an example. As I said before, it's clear to everyone who's looked at the shuttle that serious design compromises were made during development which decreased development costs but greatly increased reoccuring costs. Design the next reusable vehicles for true reusability and do it with current technology. Technology has come a long way since the early 70's. >>> As for "efficiency" ... rocket efficiency isn't going to >>> increase much. It's the physics. Recovery/repair/reuse >>> efficiency COULD improve considerably, but then we still >>> need robust and simplistic designs to make that possible. >> >>Time for a reality check. > > Been there, checked-in. Waiting for you to show up :-) > > USA porkbarrel politics work against efficiency and > simplicity - but this isn't the case in the other > spacefaring countries. If France or Russia COULD do > it all that more cheaply and better they WOULD have. > The observable reality says "This is as good as it gets". Neither is willing to spend the big bucks necessary for development of reusable launch vehicles big enough to replace their existing launchers when they're still making money on their expendables. Actually, Russia barely has money to keep flying their existing expendables, nevermind developing anything new. I don't think porkbarrel politics has much to do with it. >>The cost of fuel and oxidizer for a launch vehicle is absolutely tiny >>compared to overall launch costs. I personally like LOX/kerosene since >>both >>are widely available and the kerosene is pretty dense. > > Agreed and agreed ... it's not the fuel (even though LOX requires > a lot of energy to make and a lot of care to handle). It's the > MACHINE the fuel goes into. A machine that's typically thrown away after each and every flight. > It's the highly-trained PEOPLE required > to make sure everything's right. Parly required because every flight of an expendable is of an unflown vehicle. The full up test flight is the flight the customer paid for. > It's the huge FACILITIES and > INFRASTRUCTURE required to support everything. Sure, and a lot of that is to build the vehicles in the first place, then you throw the vehicle away and build yet another vehicle. > If these were > private ventures you'd also have to add INSURANCE to the mix. Of course, but the hope is that reusables will have intact abort modes, so a launch failure would mean you have to recover the payload and try again. With many expandable launch failures, you not only have to build a new launch vehicle to try again, but you also have to build a new payload as well. Which type of failure costs the insurance company more money, which is passed on to its customers as higher insurance premiums? > Rockets are still essentially custom-made one-off machines. > There's no assembly line, no grand template, no army of > industrial robots, no real "standard components". This makes > them incredibly expensive. Dealing with every issue the > engineers know about or can imagine makes them insanely > complex and expensive. This can't change unless designs > are somehow simplified and sufficient VOLUMES of a 'standard > rocket' are ordered so that assembly-line economics CAN > begin to have an effect. Large aircraft assembly processes are fairly similar to launch vehicle assembly processes. They're very expensive to make, so we simply don't throw them away after every flight. In fact, many aircraft fly for decades, being demoted to cargo only flights or to be sold off to foreign countries who continue to fly them for many more decades. You just don't throw away such an expensive asset when you're done with it. >>The Saturn V first >>stage burned something like 200,000 gallons of "rocket grade" kerosene >>(RP-1). If you're paying $5 per gallon for your kerosene, that's only $1 >>million dollars per launch. That's a pitiful fraction of the overall >>costs >>for an expendable Saturn V launch. And LOX is extremely cheap, litterally >>pennies per pound, in industrial quantities since air is the raw material >>you start with. One astronautix.com page says NASA was paying $0.08 per >>kg >>in the 1980's for LOX. >> >>Clearly, it's not physics that dictates the cost since the fuel and >>oxidizer >>needed are relatively cheap. > > The physics I was speaking of relate to how much bang you > can get out of a rocket engine of a given size. It's a > function of ignition-chamber pressure, subsequent gas > expansion and velocity plus the weight of the components. > X-energy IN, Y-energy translated into thrust. > > Hasn'tchanged much since the 60s. It defines the vehicle/cargo > weight ratio. You're missing the point. With the cost of fuel so low, why is the vehicle/cargo weight ratio important? Why not optimize the design for the lowest cost per lb of cargo to LEO? It's a different optimization constraint which will drive you towards a completely different design than the "performance uber alles" philosophy of the LOX/LH2 crowd. >>>>The technology is there, but to date, no one has >>>>managed to put those pieces of technology together into a vehicle that >>>>is >>>>truly economic to reuse. >>> >>> You act as if they're lagging behind intentionally. The USA >>> might, "porkbarrel politics", but not any of the others. >>> >>> I fear the real exploitation of space will ONLY become possible >>> when some drastically new propulsion technology appears. I say >>> 'warp drive', but that probably won't work. Higher dimensions, >>> inertia-reduction, funky quantum tricks ... we'd better find >>> SOMETHING or we're STUCK on this increasingly small and crowded >>> ball of rock. "Space" is simply uneconomic and looks to remain >>> uneconomic. >> >>One of the biggest problems is that it's hard to get funding to develop a >>new reusable launch vehicle. There are many reasons for this. > > Reasons 'A'-'Z' ... REALLY damned expensive !!! > >>One of the biggest in the US is that every time NASA attempts building a >>reusable, they screw it up. The shuttle was the first generation >>reusable, >>but it's clear that so many compromises were made to lower development >>costs >>that operational costs suffered greatly. > > Americans in particular, especially when political committees > get involved, always lean towards "multi-mission" designs. We > see it in American military aircraft AND in spacecraft. They > want one machine to do it all ... and wind up drastically > increasing size, cost and complexity while reducing reliability. > In part it's "porkbarrel politics", in part it just seems to be > a cultural bias. > > The new generation of US spacecraft show SOME refinements to > the 'one size fits all' mentality. They're meant to be fairly > "modular" so you can pick the booster/upper/capsule combo that > best fits the particular mission. These 'modules' are also > more 'standard', increasing production efficiency. Not ENOUGH > of course, but at least thinking has improved a bit. > >>Next you've got the X-33>boondoggle. > > Let us not speak of it ... > >>NASA picked the most technically challenging design which >>simultaneously gave the contract to a company who had a vested interest in >>the business as usual approach of using ELV's. It was a recipe for >>disaster >>from the start. For X-33 especially, it wasn't lack of technology which >>doomed the project to failure. Unfortunately for potential start-ups, >>it's >>a bit of a problem in that they have to explain why NASA failed and why >>NASA's official statement that they "lacked the technology" wasn't the >>real >>reason that X-33 failed. > > It was the butt-covering "reason" ... and still accepted > as gospel since a lot of the cover-ees are still in NASA > or govt. > >>The other really huge problem is that of supply and demand. Right now >>launch costs are high and demand is correspondingly low. Without the >>introduction of some new market, it doesn't seem like there is enough >>demand >>out there to justify the investment in a completely reusable launch >>vehicle. >>It's cheaper to develop a new expendable than a new reusable, so you have >>to >>justify those increased development costs by showing that you can make >>that >>money back over time. That's hard to do when there are so few examples of >>reusable launch vehicles. > > I prefer a completely DISPOSABLE vehicle. Build it to > make exactly ONE flight - build it simple. Designing > for re-use adds mass and complexity. It also locks you > into the one design. You've made your 'investment' and > now you're stuck. Tell that to the guys flying B-52's. They're definately not quite the same vehicles as when they were built. One of these days, the funding for upgrading the engines to turbofans will come through and they'll even look different on the outside. ;-) For that matter, look at the shuttle. There have been numerous upgrades over the years along with even more numerous proposed upgrades that were never funded. You certainly can refit existing airframes with newer technologies and keep flying them. > The easiest 'disposable' route for spacecraft is to make > maximum use of SRBs. Alone, or combined with LFRs so a > range of thrust adjustment is possible, they're really > a good way to add oomph without adding much cost. Not > much more than a tube packed with 'powder'. Only if you like paying for entirely new vehicles after each and every flight and will accept the cost and safety issues which arise from flying expendables. Intact abort is a good thing. It helps solve a lot of nagging problems with expendables independent of the whole launch cost thing. Jeff -- "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety" - B. Franklin, Bartlett's Familiar Quotations (1919) Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 17:42:07 GMT, simberg.interglobal@org.trash (Rand Simberg) wrote: >On Wed, 18 Jul 2007 17:35:03 GMT, in a place far, far away, >bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such >a way as to indicate that: > >>On Wed, 18 Jul 2007 16:23:10 GMT, simberg.interglobal@org.trash (Rand >>Simberg) wrote: >> >>>On Wed, 18 Jul 2007 15:58:16 GMT, in a place far, far away, >>>bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such >>>a way as to indicate that: >>> >>> >>>>>I doubt it. In many ways a reusable is far more complex than an expendable. >>>>>You justify this complexity, and cost, by flying it more than once. >>>> >>>> But the complexity works AGAINST you trying to re-use the >>>> component. Every component interacts with many others, it >>>> quickly gets out of hand. Why do you think there are so >>>> often last-second delays launching shuttles ? ALL those >>>> little parts have to be tweaked, for a few minutes, into >>>> harmonious operation. They can BARELY do it. Actually, they >>>> CAN'T do it ... they just fudge on the safety parameters >>>> and launch anyway. >>> >>>It is a logical fallacy to draw general conclusions from a single data >>>point, even if it's the only one you have. The Shuttle doesn't tell >>>us much useful about reusable vehicles. Particularly since much of it >>>isn't even reusable. >> >> Show me how to build a reusuable vehicle that ISN'T >> burdened-down by it's own complexity and requirements >> for reusability and I'll consider modifying my assessment. > >There is nothing wrong with complexity. A modern airliner is quite >complex. The primary difference between an air transport and a space >transport is the much higher fllight rate of the former. Um ... it's a little more involved than that. Think about it for a while. 17,500 mph in a radiation-soaked vaccuum, not to mention all the shake and shimmy involved accelerating to that speed in short order - and ultimately having to DE-celerate once again. Oh yea, the cyrogenics, the corrosives, the fuel cells, the environmental support, 0-Gee toilets, extra redundancies, what else did I leave out ? Sorry, but your hypothetical "passenger jet with rocket engines" just won't cut it. A spacecraft has at LEAST twice as many parts as the best passenger jet ... which means what, square the "complexity", or is it exponential ? Not as many 2nd-chances if things go wrong "out there" either. >The >challenge of building a reusable launch vehicle isn't a technical >one--it's a fiscal one. One has to raise the money to do so. No one, >to date, has done so, but it will likely happen, now that new markets >are being pursued, and new investment coming in. Kistler, in fact, >may yet fly, if they can get through the next financing round. Kistler ? "Kistler Aerospace K-1 is a two-stage reusable launch vehicle. It is designed to be reused 100 times. The two launch vehicle stages return from space to a landing site near the launch facility using parachutes and air bags. The K-1 reusable rocket utilizes Russian NK-33 and NK-43 Rocket Engines which were intended for use on the first and second stages of the upgraded N-1 Soviet Moon Rocket of the 1970's." The N-1 exploded. Thus ended the soviet moon race. "100 times" = 2 times, maybe. "Parachutes and air-bags" = crashes into the desert hard enough to bend-up everything. Look, the shuttle SRBs were intended to be reused many times as well. Mechanically, they couldn't take it - and the dip in salt water afterwards didn't help things either. How much stronger/heavier would they have had to be in order to be reusable ? I have no more faith in Kistlers design - I think it's a scam intended to sucker-in "economy-minded" customers. It's about six years behind schedule too. Oh yea ... Overall Length: 36.9m Diameter: 6.7m Total Lift-Weight: 382,300kg Payload: 2,600 Kg to 52 degree-800 km orbit 2.6 metric tons is OK for a "resupply pod" or the like, many satellites, even a one or two person capsule. Not much else. A "big" version with four or five times the lifting capability would be nice ... but then those parts will suffer even more from rough landings. If you're good at math you can calculate the difference in loads from radial acceleration and simple "leverage" involved in simply doubling the dimensions. Better replace those chutes with big helium balloons or build a LOT of extra bracing into the design. [note : read the saga of Samuel P. Langleys attempt to build the first passenger-carrying airplane in 1902/1903. He simply scaled-up his model ... and the thing crumbled under load. Things are rarely as easy as they seem] Now I'm not trying to totally piss on your ideal of reusuable space vehicles. Within reason it CAN be done, the shuttle is semi-reusable (but takes a lot of rebuilding after each flight), but there's a certain envelope of applicability. It's easy to re-use rather small rockets, but not large ones. It's easiER to reuse very SIMPLE rockets than complex ones. Thus reusability has a place, but I don't think it has the place you're hoping for. Quote
Guest Blackwater Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 18:22:24 GMT, simberg.interglobal@org.trash (Rand Simberg) wrote: >On Wed, 18 Jul 2007 18:13:58 GMT, in a place far, far away, >bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such >a way as to indicate that: > >>>On the other hand, we do know how to build affordable >>>space transports, with no new physics required. >> >> Well, so long as you don't mind one in fifty >> blowing itself to smithereens ... > >I do in fact mind that. Assuming I were in charge, I would design and >operate it in such a way that it wouldn't happen, since there's no >reason that it has to. SURE there are : a) complexity trumps engineering skill b) politics trumps safety c) money trumps everything >In fact, a vehicle that "blows itself to >smithereens" with that kind of regularity would in fact not be >affordable. Just like the shuttle program ... But they keep 'em flying (temporarily) anyhow because of reasons "b" and "c". Oh "c" ... I don't mean OUR money, they don't care about OUR money - I mean the money promised to the contractors, X-percent of which finds its way back as campaign donations (see reason "b"). THAT'S the important money. Quote
Guest Rand Simberg Posted July 18, 2007 Posted July 18, 2007 On Wed, 18 Jul 2007 21:20:37 GMT, in a place far, far away, bw@barrk.net (Blackwater) made the phosphor on my monitor glow in such a way as to indicate that: >>>>>>I doubt it. In many ways a reusable is far more complex than an expendable. >>>>>>You justify this complexity, and cost, by flying it more than once. >>>>> >>>>> But the complexity works AGAINST you trying to re-use the >>>>> component. Every component interacts with many others, it >>>>> quickly gets out of hand. Why do you think there are so >>>>> often last-second delays launching shuttles ? ALL those >>>>> little parts have to be tweaked, for a few minutes, into >>>>> harmonious operation. They can BARELY do it. Actually, they >>>>> CAN'T do it ... they just fudge on the safety parameters >>>>> and launch anyway. >>>> >>>>It is a logical fallacy to draw general conclusions from a single data >>>>point, even if it's the only one you have. The Shuttle doesn't tell >>>>us much useful about reusable vehicles. Particularly since much of it >>>>isn't even reusable. >>> >>> Show me how to build a reusuable vehicle that ISN'T >>> burdened-down by it's own complexity and requirements >>> for reusability and I'll consider modifying my assessment. >> >>There is nothing wrong with complexity. A modern airliner is quite >>complex. The primary difference between an air transport and a space >>transport is the much higher fllight rate of the former. > > Um ... it's a little more involved than that. > > Think about it for a while. Believe me, I've thought about it a great deal. As an aerospace professional, I've even been paid to think about it, and published papers on it. Have you? Quote
Guest Damon Hill Posted July 18, 2007 Posted July 18, 2007 bw@barrk.net (Blackwater) wrote in news:469e0d55.6399817@news.east.earthlink.net: > On Tue, 17 Jul 2007 16:05:53 -0500, Damon Hill ><damon1SIX1@comcast.netnet> wrote: > > Who sez 'alterantive' propulsion methods NEED vast > quantites of energy ? Might run on a 9v battery :-) > I wonder how to make inertia go away ... ? TANSTAAFL ("There Ain't No Such Thing As A Free Lunch" -Heinlein) > >>Get used to rocket propulsion; it's going to be with us >>for quite a long time. > > Probably - but it DOES suck. Yes, Newtonian physics are a pain. Deal with it. > > When it finally gets to be TOO much of a bother, well, > laziness IS the mother of invention. The lazy only ever talk about it. The hard thinkers and workers do whatever can be done. --Damon Quote
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