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Second Hypersonic X43 Scramjet Ready for Testing
Dan writes "I am sure most of you remember how NASA was forced destroy their first hypersonic X43 seconds in it's maiden flight, which was a big setback for the american hypersonic scramjet program. Well NASA just finished one of the final tests and is preparing to launch it as early as February 21! I wish them the best."
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Happy Trails,
Erick
http://www.busyweather.com/
I think scramjets are really the solution to low cost travel, including to low-earth orbit and space. I only hope that travel with scramjets will not end up going the way of the Concorde...
...though I bet Bush will fund it so he can land one on an aircraft carrier!! *rimshot*
webpage
This is great technology, but remember, it's not for *us*, it's for the military. Faster jets, bigger killing radius, when will this benefit freedom and peace?
"Who are in control, they are not in control of anything - they don't even control themselves!" - Glen Beck
Looks like they were forced to destroy their server on its maiden Slashdot voyage.
wasn't there plans about making a second concorde that was hypersonic?
Seems to be working fine here.
Have you been touched by his noodly appendage?
...as to other's thoughts on a nuclear powered RamJet/ScramJet. Project Pluto wasn't exactly something you'd want flying, but then again it was 1950's technology. What sort of problems do you see with something like GCNR converted for air breathing?
Javascript + Nintendo DSi = DSiCade
Well NASA just finished one of the final tests and is preparing to launch it as early as February 21! I wish them the best.
I wish them the 3rd best!
when will this benefit freedom and peace?
When it's used to destroy all terrorists.
If by 'plans' you mean some twenty-thirty year lead time ideas of 2 hour flights from L.A. to Toyko, then, yeah. But it would require a pretty serious amount of money, and like Concorde, would probably never book enough seats to pay for the flights. If you thought 2000 was a lot for a ticket...
Have you been touched by his noodly appendage?
NASA's experimental X-43A hypersonic research vehicle, securely mounted to the B-52 mother ship that will launch it, took off from Edwards Air Force Base at 3:21 p.m. Pacific Standard Time Monday, Jan. 26, 2004 for a captive-carry test scheduled for two and a half hours during which the experimental craft remained attached to the B-52.
The photograph Plane shows the B52 bomber - i'm still searching for the hypersonic baby plane
I don't know for you, but I find manned high speed flights (X1, X15) much more exciting to witness from a human perspective than those remote-controlled ones. I realize the objective is to test an engine and that there's no need to put a human being in danger to achieve that anymore, but it doesn't produce heroic stories and certainly doesn't make children dream like it used to.
I find the old crappy 1969 b/w pictures of the first man on the moon much more appealing than the Spirit panoramas, yet the probe went much further than Armstrong, and probably did a lot more science. But still, it's not the same thing, and NASA should send actually people up-diddly-up instead of drones, just because (1) there would be volunteers and (2) they would strike the public's imagination and generate sympathy for that kind of research, which in turn would turn into funding...
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
...as a scramjet takes in the oxygen it needs for combustion (whereas solid rocket boosters hold the oxygen as part of their solid fuel). Would they use the scramjet to get to such a high speed (at altitudes where there is still oxygen available) that you break free from the earths gravitational pull?
I am NaN
For the several earlier posters who seem to think that this is the Holy Grail of Earth-to-orbit transportation -- well, maybe they're right in that it's about equally unattainable. Rockets work a hell of a lot better - as has been demonstrated by almost 47 years of orbital flight.
Any airbreathing technology suffers a couple of fundamental flaws when it comes to suborbital, let alone orbital, transport. Most obvious, the air is mighty thin up there -- so you've got to stay where the air is thicker to support combustion. (Which basically means you can't make orbit with out at least some kind of apogee kick rocket).
Secondly, pushing through all that air creates drag. Now, you either aggravate the problem by slowing the relative airspeed enough to support combustion -- meaning increasing the drag on that air (supersonic combustion alleviates this somewhat), or you don't slow it down (relatively, actually you're speeding the air up), have a harder time maintaining combustion, and more significantly, have a much lower momentum delta in the exhaust -- meaning less push to the vehicle.
Scramjets have some limited use for high speed short range flight but rockets are far more efficient and the only practical way to get to orbit.
(And while I may not be a rocket scientist, I've had long talks about just this with some very expert rocket scientists, such as Max Hunter.)
-- Alastair
this will be THE means to get to a station in Earth orbit, and from there, nuclear rockets out into the farther reaches of the solar system. I'd love to see colonies on Mars as much as the next geek, but until we get it through our heads that we need to have stepping stones along the way, we aren't going to be successful. It is simply too damn expensive to develop an entirely new system for every "space objective". We need a new way into Earth orbit... and a space station whose primary objective is to be a way station where deep space nuclear propulsion systems can launch for the rest of the solar system without contaminating the environment here on earth. Maybe someday materials science will make possible the space elevator (and it may be closer than I think, but until they're spinning line, I'm not counting on it....) but until then, we need a different solution beyond out brute force approach. This could be the technology that opens up just these sorts of possibilities.
Scramjets combust the air at supersonic velocities rather than diffusing it prior to combustion the way most other engines in supersonic vehicles do. There's a lot of promise here. But in a society that can't make the Concorde profitable, will it be worth it in the end? I'd love to be able to fly to the other side of the world in something less than 24 hours. The economics of the situation seem to be against us, though.
"You can never have too many elephants on your team."
Yo, use "*rimshot*" when you're telling a FUNNY joke.
Been there done that.
When will it end?
Is this off-topic, troll, redundant or what? You decide!
The liquid fueled rockets that nasa uses today use liquid hydrogen and liquid oxygen in the reaction:
2 H2 + O2 -> 2 H2O
Which means that by mass modern rockets use about 8 times as much oxygen as they use hydrogen.
Maybe NASA could fund a mission to the Planet of People Who Know the Difference Between "it's" and "its".
keep us updated!
Mod the grandparent up too so everyone knows the context.
red rocket, Red Rocket, RED ROCKET, Red Rocket!!!
If the reactor were properly designed it's exhaust would be the same air that was put in the engine. It wouldn't be radioactive unless pieces of the uranium were breaking off and it wasn't shielded by anything.
at that speed air becomes very different due to frictional heating. the aerodynamics are also somewhat different than supersonic flight which are much different than subsonic.
the main problems are heat though. the SR-71 flew around mach 3 and heat was its biggest enemy. also keeping the engines going at that speed was a challenge - few jet engines operate with those air speeds without self destructing.
-
This one, IIRC, is built for use by Halliburton to deliver water to Iraq.
It's all no-bid, hush-hush, very patriotic and stuff.
A feeling of having made the same mistake before: Deja Foobar
I work for the Air Force, everything I do goes into this mad, mad machine. It pays my bills, but in a way it is like a drug. I work with the best technology, but as much as I love the toys, I hate the end. I guess that makes me a whore. I accept it, but I don't like it.
"Who are in control, they are not in control of anything - they don't even control themselves!" - Glen Beck
When you do a google search about "X43", although you get a page in the "Science > Technology > Space > Launch Vehicles" category, the first result is about the bus service between Calne and Marlborough.
So, why carry the oxygen, why not get oxygen from the air? For LH2-LO2, that eliminates most of the mass and solves the mass fraction problem right away. The 1960's Aerospaceplane project originally considered liquifying the O2 from the air -- careful tweaking can be enriched on LO2 over LN2 on account of boiling point differences. You used (boiled off) some of your LH2 to get the coolant.
The trouble with LACE (liquid air cycle engine) is that you have to slow down the air rushing into the inlet (or speed it up to your rushing vehicle). If you are going fast enough relative to orbital velocity, slowing the O2 down in the inlet will heat it so much that you cannot burn it with H2 and get any energy -- the stagnation temperature of the shock front gets higher than your flame temperature. Hey, if this were not the case, orbital velocity would be low compared to rocket exhaust velocity and mass fraction would not be a problem.
Ah, the scramjet, and scramjet was also considered for Aerospaceplane. It is literally the taking a drink from a fire hose. You only slow down the inlet air stream a little bit so you get some compression, and burn H2 in that hypersonic air blast and 1) hope that the flame doesn't blow out and 2) hope that you get any positive net thrust out of the works.
If you could get any single-stage-to-orbit vehicle built that had reasonable engineering margins, you could fly it like an airplane, and even if it had a very small payload, you could fly it often enough to make a profit. NASA blew a wad in the late 80's, early 90's with National Aero Space Plane (NASP) and pulled the plug. But forget the scramjet -- if you could build a rocket out of composite materials, you could get the mass fraction. NASA blew a wad in the late 90's on the X-33 and then pulled the plug.
Jerry Pournelle states that the Strategic Defense Office (which needed a way to loft Star Wars into orbit) could have done the job -- the DC-X demonstrated the control of vertical-takeoff vertical-landing (lands tail first on rocket flames just like in Buck Rogers -- maybe not so wasteful of fuel because reentry is mainly aerobraking and landing is to last applying the brakes on a mainly empty vehicle), and he talks about a program called Have Region (don't know the source of Air Force code names, although NASA these days seems to have projects code named Have Boner) that proved that the mass fraction target was achievable and one didn't need scramjets.
you certainly don't speak for me....what are you 90?
I am the Alpha and the Omega-3
... because scramjets don't work at subsonic speeds, you'd need something BEFORE the scramjets to get to mach, what, 7.
I'm sorry, i'm not seeing this as a solution to the cost of space travel at all.
At cruise in the Concorde, you could apparently feel heat from the windows due to the air friction. The SR-71's fuselage stretched over a foot at high speed. So if you're going faster again, you're going to need some pretty impressive materials to keep the fuselage together. I'm guessing metal's probably not up to it. Maybe some sort of woven carbon fibre like on the stealth bomber?
One of these days I'm moving to Theory - everything works there
According to Einstein, nothing is faster than the speed of spam. Well, maybe the ire of the spam victims, but we haven't figured out a way to harness that.
Wrong President for that won. ;-)
I am Happy too!!! And.. look I am brazilian...
I am happy with all this!!! and.. we look, I am brazilian!!!
What wonderful ways will the bush administration weaponize this sucker.
Actually i'm for it as long as we (USA) get it first.
Who needs stealth when i can fly faster than all your missles and higher then your barrage of anti aircraft.
Quick strike capability anywhere in the world in under 4 hours. Awesome.
Bom Bom, Bom Bom, Bom Bom... Row you Scurvy Dogs! ;-)
Jimi went to Heaven, you fools.
Does anyone else think that the X43 looks like a death star? Am I going crazy or have I been hanging around the Comp Sci labs too much?
in girum imus nocte et consumimur igni
This is only relevant for scramjets that use hydrogen as a fuel. If there were a scramjet which used jet fuel B, then that type of savings would be much smaller.
However, the X-43A vehicle does indeed use hydrogen for its fuel. (Perhaps for that very reason?)
The first electronic computer may have been created by the British government however it was dismantled and its information was classified so that civilians had little or no benefit from its creation.
Even modern encryption bares little resemblance to the methods developed by the military (except for the system equivalent to RSA created by Clifford Cocks in 1973 that was not declassified until it was redundant). Personally I think you have chosen silly examples.
When Argumentum ad Hominem falls short, try Argumentum ad Matrem
Disregarding speed for a moment I think the most affordable way of getting mass into orbit may just be the Space Elevator
Don't forget. That freedom you enjoy wasn't given to you for nothing. Military people are the ones who earned it for you.
Does this include OBL? Storm troopers? Palestinian suicide bombers? The US soldiers at My Lai? Have you forgot about pacifists such as Gandhi and M.L.K.Jr.? Do these military super heroes win Nobel prizes or do they just rape women overseas? Are you sure that US military isn't a destabalizing force in the region where the grandparent post lives? Or does freedom require sacrifice of the blood of innocents overseas for presidential popularity boosts? What about racisms and concentration camps that appear as a result of war?
A very large portion of the overall mass (and price) of current space transport is just the fuel to get out of the atmosphere.
A perfect statement of one of the most persistent and erroneous misconceptions in astronautics. Price it out: rockets typically burn on the order of 200kg fuel to put a kg payload into orbit (double this for manned, halve it for simplest payloads). LOX is around $0.16 (USD)/kg and kerosene around $0.40 (USD)/kg. Burning 2.5:1, you pay $0.22/kg fuel, or $45 per kg into orbit. Now add tankage, engines/motors (hella pricey, used once and tossed or essentially rebuilt), systems integration, logistics, infrastructure, admin overhead, and you get ~$9,000/kg delivered. Fuel is only 0.5% of the total cost. It is left as an exercise to the reader to figure out why our space program is so inefficient.
To recap this week's lesson for rocket scientists and voters: know some numbers before throwing your weight behind multibillion USD expenditures.
Sources: astronautix.com; Wertz, Space Mission Analysis and Design, 2nd ed., Microcosm: 1992, p. 731.
First rule of government spending; why build one when you can build two at twice the price?
http://merkle.com/pluto/ A great story about Project Pluto - "The Flying Crowbar" - a nuclear-powered cruise missle from the late 1950s.
I understand that supersonic combustion is a neat trick, basically the flamefront has to keep up with the aircraft as it moves through the air. Since normally a flamefront is limited in its speed by the speed with which the molecules can contact each other and thus react chemically, getting that flamefront to keep up with the aircraft involves getting the local pressure high enough that molecules can bump together at "supersonic" speed (I doubt it is actually supersonic in the region and under the temperature/pressure conditions of the combustion).
But how does one exert pressure against something that is not there? Imagine the classic balloon we blow up and then release. The pressure differential between the front of the ballon and the area where the air is escaping causes the balloon to move. Pop the balloon with a pin and it goes nowhere, because the pressure is released everywhere at once. A ramjet compresses purely from the ramming of air into the combustion pipe. Without a compressor against which to enclose the combusting mixture, how is thrust generated?
Something I'm missing. We know it works, we've seen it. It just doesn't make sense yet.
To hear the gods laugh tell them your plans.
It'll take at least 10 years to bring this to a production anything. Bush will be long gone, as will his successor.
To hear the gods laugh tell them your plans.
The freedom I enjoy was actually conceptualized by the philosophers. If it were earned by anyone, it would be Voltaire.
The military is most definitely a significant tool, but without any ideas to direct it... well, look at China.
So quit pulling my strings about some mythos of the military. It is a poor justification for the monies spent, and even worse in how it serves the population at large (as if no technology is developed outside military applications).
Without the philosophers, you don't even have the concepts like "freedom" to fight for.
Scramjet technology began around the 1950's. It has been since the 1970's research in to plasma torches in supersonic flows. The plasma torch servers as an igniter and combustion enhancer. Plasma torches offer a couple of advanrages. The plasma torch servers as an ignition source for the fuel and combustion enhancing radicals produced by the plasma torch.
Scramjets also use the hypersonic shock wave for compression. A high compression "point" is where the forebody and engine fence shock waves cross. One of the problems faced it is how to design the inlets to maximise the compression. To keep things simple many scramjet engines are designed as 2D engines.
Designs my attempt to use air stream swirl to enhance fuel and oxidizing air mixing.
For more details please see http://citeseer.nj.nec.com/cache/papers/cs/3623/ft p:zSzzSztechreports.larc.nasa.govzSzpubzSztechrepo rtszSzlarczSz1998zSzaiaazSzNASA-aiaa-98-2506.pdf/r ogers98experimental.pdf
Oh come on, this is at least as funny as any Far Side comic.
I am an vegan and my Ike you is
Wat was the queschin?
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Nope, sometimes it stands for "it has," as in, "it's been going on for too long."
Just send folks here.
What bothered me even more than the misused apostrophe was the missing word in that same sentence: ...NASA was forced destroy..."
It seems that they could do with a pioneer of ramjet technology like Roy Marquardt. The engines his company built had a very high reputation, both in the high atmosphere and in orbit. 3000 miles per hour is just the beginning...and that was the 1960's. See: http://www.jacobsmeyer.com/Marquardt/Chapter_1.htm
Sure, there is a modest up-front cost, but once it's built, transportation to geo, HEO, and beyond will be relatively inexpensive.
It may sound unfeasible at the present time, but the US congress is funding research on it.
Those who sacrifice security to condemn liberty deserve to repeat history or something. - Benjamin Santayana
Everyone who goes on a space mission is making a conscious and informed choice to take a risk, whether they used to wear a military uniform or not. Are you saying that "civilians" are somehow not capable of understanding the risks of space flight and shouldn't be sent?
I suspect that underlying this view is the attitude that women dying in a space craft is somehow more tragic and less acceptable than men. If so, that's horribly patronizing.
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
But why would they keep the top speed secret after they have been decommissioned?
three other people already mentioned that. Eh, overkill is a way of life.
I find it humorous enough the moderators felt it necessary to moderate you off topic while leaving the parent post alone (what about 7 mod points). Basically, you win you sly devil trickster. Trolling moderators, what a novel idea.
But do you really want to see a spamic boom?
A blog about stuff.
I was just curious why so many seem to be pushing nuclear rockets on slashdot lately? I know that radiation fears are irrationally intense in this country, and certainly the thermo-electric nuclear powerplants on probes posed no risk. HOWEVER, that isn't even in the same league as a nuclear rocket. Would the fissile material in a nuclear rocket be as strongly encased as the stuff we send up now?
Is that even possible? The probe power sources aren't throttlable-- they just keep dumping out power and heat at the same rate 24/7 (decreasing as the material decays I guess). With a nuclear rocket, on top of being alot more material, has different design requirements.
Flamebait???
Some people have no sense of humor.
What is it called when you tag on a line like "I wish them the best" in this way? It reads as an attempt to develop a peer relationship between the subject of the blurb and the author, which is inappropriate here. The words I was thinking of are pandering and ingenuine, but pandering is way too harsh, and means "pimping" (not quite right), and ingenuine is not even a word.
So what is the right word?
(This is another attempt at geek PoMo Deconstruction.)
Isn't it amazing the number of 'rocket scientists' on slashdot...
Project Kholod
Perhaps it isn't new, but it certainly hasn't been done to such an extent until now.
The first X-43 vehicle and its Pegasus booster were lost shortly after release from the B-52 over a restricted Navy Pacific Ocean range on June 2, 2001, when the combined vehicles deviated from the flight path and were deliberately destroyed.
I dunno, when I read this, I wonder if the X43 that was 'deliberately destroyed' was unmanned or not. Do we still use test pilots? Did little Mr. Crotch Rocket go kerpow and get forgotten in the PR?
Dan, are you a greengrocer or an idiot?
And as for the Nazis developing the first jet engine, Sir Frank Whittle might have an argument with that. (Although the Germans may have had a jet -powered aircraft in the air first.) :)
IIRC, according to "Inventions that changed the world", Whittle patented his jet engine quite early on (I think before he'd built a working version) which meant that it became public knowledge.
It's quite possible that the Nazis saw this patent and, of course, probably didn't feel the need to pay any licencing fees for their development
Here is a picture (rendering) of this X43.
I think these names are cool, but these names for the electronic warriors are very different from the more macho names for the gun and bomb warriors.
I don't know what all of the fuss is about - The Team at the University of QLD has had a number of successfull hypersonic flights... (ANd their budget is way below the US spend).
Re scramjets and human flight --- the acceleration will kill you. These things will be good as a) missiles, b) anti-missile missiles, and c) Launch LEO (Low Earth Orbit) Satellites.
Peer
True story, I live in Virginia Beach, Va. Going into my neighborhood the other day was a car with the NASA Meatball logo and the customized vanity plate "HYPER-X" or "HYPERX" I used to work @ NASA Langley for a contractor (Atmostpheric sciences) and I remember seeing the same car over there on center. I don't think the person with the red sports car lives in our hood, maybe just visiting. I thought I would share this with you. That is all.
Southeastern Virginia REPRESENT!
The Article does not mention this so I thought I would let you know. The X43 is built by the LSG division of Orbital Sciences in Chandler AZ as well as the Pegasus launch vehicle. And yes, rocket science is tough. -Dan
There was a project back in the '80s, codename Jetfire that did this.
--
"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
Nope. That's the stochiometric ratio, nothing like that is ever used. Actually it's more like:
4 H2 + O2 -> 2H20 + 2 H2
(Actually, it's much messier than that, you really get a bunch of HO's O's H's H2O2's but that's the gist of it).
The point is rockets run very fuel rich, because that gives a much higher exhaust velocity (the hydrogen has less places to hide energy than complex molecules- you want as much energy as possible to be in kinetic form), the scramjet would do the same thing. So your fuel/oxidiser ratio is way off.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"Not carrying the oxidizer saves weight. That is the basic mechanics of the idea. BUT there is another area of design mechanics that could promise to save even MORE weight: Reduce the vehicle mass to bureaucrat ratio. For each NASA pencil pusher not paid to add ABSOLUTELY NOTHING! to the Space program, we gain a small, but measurable incremental move forward in Man's reach for the stars.
- Minutus cantorum, minutus balorum, minutus carborata descendum pantorum.
You state Greed being the largest stumbling point to which I question what is at the root of greed?
I would go the final step and say that the largest downfall of man is Selfish Pride.
The X-43 itself is build by Micro Craft. Only the Pegasus is build by Orbital. http://www.dfrc.nasa.gov/Newsroom/FactSheets/FS-04 0-DFRC.html
see subject
Being 2 years later than Australia's 2002 hypersonic flight, it's more of a formality.
This is not too different of a problem from that which confronts the "hydrogen economy." I seem to recall reading that the most effective way to get hydrogen atoms packed into a tiny space is in fact the trusty carbon atom. So yeah, liquid hydrogen doesn't have that much mass, but, to get the same effect as burning a gallon of gas requires some absurd amount of more volume. I wonder, really, what the tradeoffs are?
This is my sig.
"Drink from a fire hose" is a term used to describe freshman year at places like MIT and Caltech -- you have research-oriented faculty given the liberty to teach introductory courses at whatever level they chose, and a lot of the material goes over the heads of even very well motivated and intellectually capable students. The students figure they can benefit even if they only retain a tiny fraction of this stream of knowledge pouring by.
I suppose in taking to the Grammer Police, anything I write can and will be used as testimony against me, but I argue that the fire hose is a metaphor here -- "Her breasts are like twin gazelles" from the Song of Solomon in the Bible is more simile.
When I said "literally taking a drink from a fire hose", I was using a phrase familiar to many Slashdot readers, but taking it out of the realm of metaphor, past simile, and into accurate physical description. The scramjet is like the drink from the fire hose in that 1) the scramjet encounters a highly energetic fluid flow, and 2) the fluid flow is so energetic that it cannot trap, entrain, deccelerate, or otherwise control that flow; it can only hope to interact with that flow weakly in the hope that it obtains the desired outcome (i.e., slacken thirst from the fire hose or obtain useful thrust by burning fuel in a barely-deccelerated hypersonic air stream.
When I used "literally", I was aiming midway between "is exactly" and "is very much like." No, the scramjet is not the fire hose drinker, but the comparison is stronger than simile. We talk of a literal translation -- a word for word mapping between two languages. I am arguing that there is an equally strong correspondence between the scramjet and the fire hose drinker -- highly energetic fluid flow, requirement to weakly interact with the flow because strong interaction would have catastrophic consequences, challenging technical requirement to have weak interaction with flow and still accomplish objective.
Dear Coward:
Every point is obvious once you get it, but you still don't. Don't pout! You're not in bad company. Every astronautics student I've ever met and even one astronaut candidate I know were off by at least an order of magnitude when they guessed the fuel cost of space access.
The consequence of this misconception is too much emphasis on fuel efficiency, and not enough on operational efficiency. For example, what if you built a shuttle that cost half as much to turn around between flights by having such massive tankage and engines that it had to burn 10x as much fuel to put each kg into orbit? The vehicle would be 2.15x bigger than the Shuttle in each dimension and its fixed cost would be 10x as much (per your intuition). But for Shuttle, fixed cost is on the order of 1% of the total cost when you run it out to 100 flights. OK, now your fixed cost is 16%, and fuel is 8%. By pink-slipping half the standing army of 6,000 people required to turn the Shuttle around, you've still managed to make space 65% more accessible on a fixed budget.
(BTW, this example is very unfair to Rutan, XCOR and a few others working on robust, reusable launch systems of moderate performance. These guys are targeting operations cost reductions well in excess of 90%, with much less mass gain than in my example. Also, reduced operational demand can result in a higher flight rate and longer vehicle life - a virtuous design cycle. Rutan et al are aiming to make space more than 1,000% more accessible.)
Engineers lured by the siren song of fuel efficiency have also often chosen exotic, toxic, low-density, and/or cryogenic fuels. All of these qualities increase dry mass a little and operations expense by a lot when compared to boring old kerosene or alcohol. All offer very modest gains in performance for a first stage or during early stages of flight, when you burn the most fuel.
So, Dude, to sum up, you correctly assumed fuel volume would relate to fixed cost, but incorrectly assumed fixed cost was dominant. You also did not even try the exercise I left for you in the prior post, so you flat-out missed the fact that operational costs dominate. Too bad. Operations is the most decisive factor WRT how soon you you'll be able to buy a ticket to orbit.
I am not an aeronautical engineer, but hopefully someone who is can give an insightful answer to my question?
Why can't you construct an engine which can change its shape depending on the velocity of the gases flowing through? If you could shift position of the nozzle and/or the inlet, away from, or into, the engine, then you could combine the functionality of a ramjet and scramjet into one single engine. You could also apply the same principle to rocket nozzles - change the form of it in order to adapt to changing air pressure at higher altitude.
Of course, I understand that it would be difficult to construct such a complex design that can withstand the forces - but the idea is similar to that which is used in thrust vectoring, right?
nt
Do you even know anything about perl? -- AC Replying to Tom Christiansen post.
What is this some bad seinfeld joke turned into a troll?