Sometimes there are unexpected side effects of Samizdata posts. My discussion of the Blackstar project last week had that in spades. When Mike Lorrey posted some technical information defending the possibility such a vehicle might be real, I sat up and took notice. Amongst things I knew about he described something I was completely unaware of. There is a safe Boron gel fuel. This led to an exchange of emails and Mike kindly produced a paper on that and several other important technologies and basic concepts of spaceplane design.
NASA got the spaceplane design so badly wrong on the Space Shuttle one hardly knows where to start. Mike shows the science behind some of those truly awful design choices. First off is wing loading. Virtually everyone in the business knows high wing loading on a manned re-entry vehicle is not just a bad idea, it is almost criminally insane. Once you go down that route you are forced into ever more dangerous and ever more marginal design decisions. High wing loading means there is a lot of vehicle weight per square foot of wing. It means more kinetic energy has to be dissipated over a smaller area. It means the re-entry interface happens much deeper into the atmosphere. It means you cannot skip and bleed off heat. It means you need heavy thermal protection systems… and on and on.
The key bit in his paper though is the Boron Gel. I must say this mythical substance was one I knew very little about and what I had heard was it is more closely allied to a chemical weapon in toxicity than a rocket fuel! But according to Mark there is more than one way to gel a boron, and this one is a boron/keresene slurry.
Why does this get me excited? Another factor pretty much everyone knows is liquid hydrogen is a really bad fuel. Yeah, it has a high ISP (a measure of how good a fuel/oxidizer combination is) when used with oxygen, but the problem is density. It is horrible for density. You need gigantic tanks to carry a reasonable amount and the tankage and associated structures weight eats up all the gain from using the stuff in the first place. On top of which, it bleeds off. You can not make hydrogen stay put. It is useless for long voyages or for a long stay in orbit. That is why upper stages use really nasty, evil and deadly fuels that happen to be liquid at room temperatue and are hypergolic (ignite when mixed).
Even if your fuel is not as ‘good’ as hydrogen in absolute terms, it can be better in practical ones. A very dense fuel means smaller structures to hold it and that means less weight to orbit which means less fuel to carry the fuel… you win points in your rocket equation. Dense fuel is a big win. Dense fuel that also has a very good ISP is a very big win. The Boron/Kerosene mix appears to be just what we need.
What I look forward to finding out now is: what is required to handle the stuff safely? Is it truly not in the high danger category of the other Boron Gel technologies?
If you feel yourself called to the label ‘rocket scientist’, go read Mike Lurrey’s paper. I await your comments.
very interesting.
But howcome NASA makes such bad desisions ?
Whats going on?
I think that all this rocket science business is way off topic for the prime agenda for this site. However, it’s darned interesting, so let’s try to push it along a bit.
Mike Lorrey makes some excellent technical points, both about getting off the ground and and re-entry. However, on the whole, I think it would be unfair to be too critical of the historic NASA performance. Don’t forget that they actually got a man on the moon and safely back again in the 1960s with Apollo. Pioneers always have to do things the hard way, otherwise The West would have been explored by men in 4WD air-con vehicles supported by helicopter air drops instead of on horse-back.
Recall that in the 1960s computers were very primative by today’s standards. One of the first airborne computers (Verdan) had a memory of only 1024 words of 32 bits, stored in bulky ferrite cores. For Apollo, computing power was at a premium and inertial navigation and alignment systems (and Kalman filter implementation) were relativitely crude. This meant that re-entry was a fearfully critical phase: too shallow an angle would cause a skip that would prevent the returning crew from ever getting back to earth, whereas too steep an angle would cause burn-up.
My suspicion is that the NASA people who specified the space shuttle had these delicate re-entry issues heavily in mind and, perhaps not unreasonably for a man-rated system, adopted a very conservative design, even though it did require high-maintenance ceramic tiles. For the chosen mission design it might be difficult to substantiate a claim that NASA got the Apollo wing loading wrong.; the vehicle was not intended to hop the atmosphere and its wing needed to be compact for launch. One might equally claim that designers of the Tornado got the wing loading wrong; it needs a high loading for low-level terrain following to a target, but a much lesser loading for its high-altitude air defence role. Consequently, one could say that in neither regime is it optimum.
As for fuels, yet more compromises are necessary. Mike Lorrey is right to point out that textbook emphasis on specific impulse is far from the whole story. Handling difficulty, cost, toxicity, storage properties, etc, are other factors, and density is clearly important when it comes to minimising fuel tank structural mass.
Designers who have the benefit of starting with a clean sheet of paper will always have some advantage over government design teams who have perforce inherited a methodology and a supporting infrastructure that they are expected to make best economic use of, plus they have the advantage of later technology developments. Mike Lorry shares some of these advantages – may one sincerely wish him success in his choice of parameter optimisations.
The Brit built space shuttle is much better than the USA design.
Or at least it would be if Brits could actually design and build a shuttle.
Just as the Brit Mars probe was better than the American probes.
Or it would be if it had worked. (Yet another USA probe arrived in orbit around Mars this week.)
Rocket science off topic here? Hmmm… One editor is part the management of the National Space Society and another one is named deHavilland. A bunch of engineers from places like XCOR are regular readers and commenters… Hmmm…. 😉
Most of what you say is true but does not really affect my case. First off, I did not attack the design of the Apollo-Saturn system. For what it had to do, it did the job well and actually was a fairly clean design. Note that the Saturn first stage used Kerosene/Lox… I can argue about the Apollo program and alternatives but I would never call it a poor design.
The original shuttle design was a much saner vehicle. The problem was, they could not get it through congress… so they got other government agencies, in particular the DOD, to buy in by asking what their requirements were, then piling those on, redesigning a spaceship into a camel in the process… then to make the budget they effectively shortened the legs and cut off the hump. We have been paying for those mistakes for 25 years.
The problems of high wing loading for re-entry are not something new. People have been talking about this as long as the shuttle has been around and longer.
I think it is safe to say that any winged commercial spacecraft will have low wingloading to ease the re-entry requirements as that is one of the big humps to be crossed for commercial orbital flight.
But what I really want to know is more about Boron/Kerosene slurry!!!
Pioneers always have to do things the hard way, […]
Indeed. A fair bit of any endeavor is finding out what not to do, and that experience is often earned the hard way.
The problems of high wing loading for re-entry are not something new. People have been talking about this as long as the shuttle has been around and longer.
As I was saying….
Of course, low wing loading can complicate getting into orbit in the first place.
I have to say, I’ve always wondered what the link between libertarian politics and space travel is, other than perhaps the interesting contrasts between approaches adopted by massive state-funded enterprise, the private sector, and the former Soviet Union.
I’m not sure I quite follow the point about why the wing loads make it harder, not easier, to bleed off speed (being a modern languages graduate, not a rocket scientist), although it’s interesting to see that the idea of skipping off the atmosphere to slow down seems to be so reliable now that we can do it on Mars trips.
And I suppose you could write a long book about poor Shuttle design decisions, not least the damning fact (that usually gets oddly overlooked) that in both fatal accidents, it’s not hard to envisage some fairly simple ways of keeping the crew alive.
Dale,
Boron based fuels (TEB…..Triethyl borane) were used in the SR-71 program either to light the engines (J58) or light off the afterburner.
TEB is ‘heat stable’ and combusted on contact with JP-7.
Anytime you see colour photos of SR-71s or YF-12As showing a green hue/colouring of the engines exhaust it is likely burning Boron based fuels.
If I remember correctly fluorine was an option additive for JP-7.
As a side note, the GE/RR bid to be the second supplier of engines for the JSF has been/about to be canned by the States due to concerns of ‘technology transfer’ leaving P&W as the sole supplier. P&W is the only gas turbine manufactour with extensive Boron based fuel experience.
However, TEB is not what I am asking about. I am interested in the safety and handling characteristics of the boron/kerosene slurry Lurrey is discussing:
“This appears to be true, as the Onera chart, shown above, show that a 55% boron / 45% kerosene slurry exhibits an Isp increase of 50-100% over kerosene in a ramjet, varying based on specific thrust. As you can see, the boron provides both Isp boost and densification of the fuel (which goes to help improve fuel fractions). This would boost the volumetric Isp of kerosene to 490 seconds up to as much as 650 seconds. NASA HEDM Program papers9 state that the gravimetric improvment in Isp between 31-35 seconds for boron/kerosene slurries, so it appears the primary benefit is that boron densifies the fuel while providing modest improvement in gravimetric Isp.”
I don’t know anything about this, but here’s a man who does:
http://www.jerrypournelle.com/mail/mail404.html#boron
and he seems to think the whole boron thing sucks dead bunnies.
So who’s right and who’s wrong here?
I do wish everyone could really get these things right about space ’n’ rockets and stuff.
We’re never going to get anywhere until they all get built out of scandium aluminide. Light, very much so, melts at 1,400 oC, super stuff.
We simply need to make all designers aware of this and get them with the programme.
Me? Sell scandium for a living? What makes you think that?
Dale,
I think some of your friends may be able to get you these there papers that are unavailable online….
http://library.nps.navy.mil/uhtbin/cgisirsi/oe8qBt7SXe/SIRSI/84680008/5/0
http://www.stormingmedia.us/46/4656/A465632.html
http://www.stormingmedia.us/13/1335/A133512.html
I for one would be very interested in reading Urbon’s thesis.
Jerry has not often been known to hold an opinion moderately, but his discussion on this seems quite good. However it is mostly about the fuels used in jet turbines and on the rather nasty fuels used in those days. There is nothing there about the boron/kerosene slurry Lurrey talks about.
Some of the people referred to here are likely some of the same people who conferred with some people I know when they looked at the idea some years back and decided against looking further. The thing is, Lurry purports to have a different type of Boron based gel than these old studies talk about. There is the issue. I have never heard of his fuel before and if it is anything like what he says I want to know more.
And just to be clear… I am a currently a methane/LOX fan myself but have no particular religious convictions on the subject. Kero/LOX is also quite good, which is why XCOR is using it for the XRacers. Well, the fact that it gives a nice long orange flame had something to do with it too 🙂
In the interests of consolidating links to be easily found, here are a couple references from Jerry Pournelle’s discussion. They are all quite interesting and the use of nanoparticles shows this is really new work:
http://aerodyne.technion.ac.il/~rocketw3/gel_propellants.htm
http://www.freepatentsonline.com/6652682.html
http://www.mdatechnology.net/techsearch.asp?articleid=604
Well, kero/LOX are cheap, available, relatively easy to handle, proven… which makes them a good choice – but you have the SI compromise to make.
The problem I see with any analysis is we keep coming back to having no single, sane, solution – it’ a real PITA frankly. Wings are handy for coming into land, but a pain for getting through the atmosphere and getting back into it when you’d rather have something a more sensible shape.
I did like the DC-X for that, but that concept leads to other problems.
Well this all sounds very promising, when can we expect Mr Branston to have 2 hr flights to the Antipodes operational?
Well this all sounds very promising, when can we expect Mr Branston to have 2 hr flights to the Antipodes operational?
Sadly, probably never.
I fear that fast conventional aircraft won’t make much sense economically and ballastic vehicles won’t please the passengers – I think Clarke wrote, “who would use a vehicle where for half the trip you can’t go to the bathroom and for the rest you won’t want to…”
Another issue is a lot of the traditional arguments for needing faster air travel are being eroded. At the high end, the problem was about time. Time being jet lagged, time being out of the loop.
I just flew back from Hong Kong where I was bumped to First Class, Cathy Pacific. I had a large bed to sleep in; I had a large desk to work at. There was inseat power for my laptop, noise cancelling headphones (although I do have my own) and an internet connection.
The Cathy net connection was limited to email, but I know that on SAS and Lufthansa the broadband is good enough for Skype to work well.
All this for about $10,000 which would be a lot less than the ticket on a trans-sonic vehicle. I typically fly around 150,000 miles a year, mostly long haul and would love to spend less time in aircraft. The reality is I have enough trouble getting my employer to part with the cost of an Economy+ ticket, let alone Business Class.
Even when Concorde was flying, the only way I got to fly on it was to pay for the ticket myself.
NEVER???
Crivens, man, that’s hardly the spirit that built the empire/tamed the west/got me where i am today.
I’m admittedly not an engineer, and from the little I’ve gleaned from the technical discussions here, I can appreciate that there are huge technical/economic issues to overcome, but I can’t help but think that the state of commercial air travel today is rather like sea and rail were when people first started flying – rather slow, but with adequate comforts for those that can afford it, and all the competition based around differentiation in that area.
There is clearly an absolute goldmine waiting for whoever can crack this particular nut…
I’ve always assumed it’s because there’s no government in space (yet!).
One of the reasons that I stood up and took notice of the AWST article is that they used the term ‘boron-gel’ fuels. Back in the classical rocket era, the boron fuels they used were not gels. Diborane, pentaborane, TEB, etc are not gels, they are rather fluid. Diborane and pentaborane had a tendency to burst into flames when exposed to air. I can imagine why TEB was needed to ignite the SR-71 fuel, given it was formulated with a very high flash point for thermal protection reasons.
NASA’s HEDM program looked at gells of helium cooled solid H2, and Kerosene, using aluminum, boron, titanium, and carbon. One thing they did not do, apparently, was to produce nano-scale particulates of the gelling materials. According to a 2001 Navy patent, producing nanoparticle gelled fuels provides even higher performance than the HEDM study showed, because by using nanoparticles, the net surface area of the particles is vastly increased.
One interesting phenomenon I’ve seen was that prior to the AWST article, the prevalence of papers and pages online about boron fuels was few and sparse between. I did most of my research for this article then, as it is part of a business plan I’ve been working on. Since then the number has virtually exploded, as if the search engine companies got a lifting of a gag order on indexing pages using the term ‘boron gel’.
This all being said, I suspect that the need for boron gelled fuels may be past. The “Blackstar” system described by AWST did not use any airbreathing propulsion in the second stage, which was launched at Mach 3 by the mothership.
In the last 5-7 years, advanced airbreathing hypersonic propulsion systems have been developed that allow the extremely high Isp of air-oxidized thrust up to around Mach 10 or higher. Current materials technologies (other than SHARP materials) used in the X-43A indicated thermal damage beginning at mach 9.8, according to sensor readings. For this reason, I suspect that Mach 10 is a reasonable practical limit for airbreathing propulsion.
Even so, this gives the key advantage for SSTO RLV: the high Isp of airbreathing, combined with the lower Isp of a rocket mode (as seen in RBCC concepts) for the mach 10-25 region, average out with effective average trip Isp above 600 seconds or more. This high avg Isp allows mass fractions between 0.60-0.75, allowing vehicle builders to use more conventional airframe design and build on production lines.
Given this, and seeing as how every high tech program at NASA that would contribute to a 2nd generation RLV (SHARP, RBCC, TBCC, GTX, etc) has been scuttled and shuffled off to classified projects at DARPA and other mil labs, it appears that Blackstar is mothballed because it is being replaced by a real 21st century launch system.
The NASA “Back to Apollo” trend is a risk averse strategy for public consumption, but also to keep government money from supporting the expansion of public space travel. The last thing they want is a bunch of libertarians running around in space, free of overbearing governments and showing the world what truly free men and women can do with government out of the way.
I can’t help but think that the state of commercial air travel today is rather like sea and rail were when people first started flying – rather slow, but with adequate comforts for those that can afford it, and all the competition based around differentiation in that area.
There are fairly tough engineering problems associated with getting through the thick “soup” that passes for our lower atmosphere.
However, to consider your other point. Air travel has become more available and cheaper, especially as the availability of aircraft and more “interesting” business models has increased. However, at the end of the day, while aircraft can fly further, the performance characteristics of a modern airliner are pretty similar to the DeHavilland Comet (an airframe still in use 50+ years after it first flew).
Likewise, modern diesel electric trains don’t offer a huge number of speed advantages, in most use patterns, over steam.
Some ships have improved though, Sea-Cats are a huge improvement over standard taxis.
I can’t see things changing all that dramatically on the airtravel front, especially for the mass market, over the next 25 years.
A third number, of equal importance to Isp and mass fraction, is the total delta V to orbit. Mitch Clapp has shown that for a hypothetical lox/kerosene SSTO vehicle, the delta V is 29,000 fps; whereas for a comparable lox/hydrogen vehicle, the total delta v is 31,000 fps. The hydrogen fueled vehicle incurs much higher gravity losses and somewhat higher drag losses. The putative advantage of the air breathing vehicle’s high Isp disappears when the very large drag losses are taken into account. Discontinuation of NASA’s air breathing development programs, therefore, rather than hurting the development of cheap space transportation, benefits the American taxpayer.
A disadvantage of hydrogen fueled rockets, not mentioned in the article, is their low thrust to weight ratio compared to kerosene engines. This two to one thrust to weight ratio advantage in favor of kerosene engines is inherent in the design of pump fed rocket engines. Since pumps pump volume and not mass, and since the turbo pumps comprise most of the mass of the rocket engine, the low density of liquid hydrogen, Mike pointed out, means that liquid hydrogen engines can never approach the thrust to weight ratio of hydrocarbon engines. The best thrust to weight ratio achieved by hydrogen engines is about 60 and the best achieved by hydrocarbon engines is about 125.
Dale, XCOR developed the engine that will power the Rocket Racers to power their suborbital vehicles. The engine burns kerosene for two reasons. First, kerosene gives a better Isp than isopropanol and second, it is cheaper. The beautiful plume of hot flamey stuff is only a side effect. 😉
Mike, I do not know where the idea that there is high-level opposition to private spaceflight in United States comes from. There is broad bipartisan support, nay, enthusiasm, for it in the U.S. Congress and at the highest levels of the Bush administration. It is true that Dan Goldin tried mightily to prevent Dennis Tito’s flight, but the overt sabotage that low-level NASA employees perpetrated against Amroc many years ago is no longer in evidence. Last year, Representative Oberstar introduced legislation that would have killed private spaceflight, however, that bill seems to have had little support and no chance of passage. The facts do not support a conspiracy theory here.
I’m personally skeptical of the existence of Blackstar. Dwayne Day has outlined good reasons at Transterrestrial Musings. I would not place my hope for cheap space transportation on the existence of a boron containing fuel. Enabling technologies are long life engines, lightweight structures and rapid turnaround and cheaper propellant. Burning boron is neither cheap nor conducive to long engine life.
I’m rationally skeptical of Blackstar, but the degree to which the ICBM-industrial complex is frothing at the mount trying to debunk the story, to a degree I’ve never seen, makes me suspicious. I’m wondering when Jeff Bell, the rabid self described “recovering space access advocate” is going to show up at my door to drag me off to a deprogramming session.
As for boron, I’m personally not fixated on it. There are a number of issues and conjectures that demand more research and testing outside the clutches of the PTB.
I’m not one to believe in explicit conspiracies. Buraucracies and other institutions, and those that work in and for them, exhibit behaviors that may overtly appear to be conspiracies but are merely the creature protecting its turf mindlessly.
If you’d read up on SHARP (or just my article), you’d see that the hypersonic drag allowed by SHARP edged vehicles is reduced by 90% versus typical blunt edged and nosed hypersonic bodies. This translates to a massive reduction in the drag to be expected in an air breathing launch vehicle, thus the delta-v requirements are back in the area of Clapp’s projections or less, because of the lack of need for large LOX tanks. Avoiding turbine-based combined cycle in favor of rocket based combined cycle propulsion, while there is significant drag in ramjet modes, ramjets still get significantly higher Isp than the low drag SCRamjet mode, on a net thrust/drag basis.
My view that high level NASA opposition to public space access exists is based on more than AMROC: Beal Aerospace, Lutz Kayser, GTX RBCC, SHARP, Gerald Bull, United Space Alliance’s actions against SpaceX, are just a few of the many examples of US Gov’t interference in private launch efforts or stifling of its own advanced research. It goes beyond these examples. If you’ve read USAF Spacecast: 2025, you may note that in their future scenarios, they view the libertarian/transhumanist/space access movement as a threat to national security.
Lee: I was being a bit tongue in cheek about the flame… but some of the XCOR folk have specifically said the visible flame helps with the drama and excitement of the event, and those are major criteria for making the races a major sports event.
Lurrey: Could you supply a link to Spacecast 2025? I do not seem to have a copy and I did not find the pdf via google although I found parts of a 1996 study series under the names 2020 and 2025.
Lee: I was being a bit tongue in cheek about the flame… but some of the XCOR folk have specifically said the visible flame helps with the drama and excitement of the event, and those are major criteria for making the races a major sports event.
Lurrey: Could you supply a link to Spacecast 2025? I do not seem to have a copy and I did not find the pdf via google although I found parts of a 1996 study series under the names 2020 and 2025.
Dale, I think it’s a tad more complicated than that… The current Space Transportation System is indeed complicated to operate in part because many different users have (or rather had?) to be accomodated. That is one of the reason why NASA’s quasi-commercial Shuttle operation in the 1980s was slow and cumbersome. But a great deal of the Shuttle’s problems can also be attributed to the fact that the required high-performance technologies didn’t work out as planned. The fully reusable two-stage-to-orbit Shuttle would not have been immune to those problems! For example, the TSTO would have utilized FOURTEEN Space Shuttle Main Engines (12 on the booster, two on the orbiter) vs. just three on the current version! You mention thermal protection concerns, but the TSTO Shuttle would also have had problems since the booster was to be the size of a 747 Jumbo Jet and its thermal protection system had to be capable of withstanding Mach 10 flight which is almost as bad as orbital spaceflight…
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It is easy to criticize the current Shuttle, and it does have some serious safety flaws which are attributable to shortsighted decisions made back in 1972 when the design was finalized. Ironically, one of the main reasons for doing a partially reusable Shuttle was lower technical risk. The current “thrust augmented orbiter system” (TAOS) Shuttle has no integral propellant tankage to speak of, mostly utilizes conventional aircraft materials and “skin-stringer” construction techniques (the TSTO orbiter would have been a totally different beast). Also, TAOS is less sensitive to weight growth than the original reusable TSTO shuttle would have been. And despite this, NASA & its contractors still encountered all kinds of development problems!
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I don’t know if cheap & frequent access to orbit is feasible today, but it certainly seems the technology just wasn’t ready when the Space Shuttle was being designed. I think the X-15 (which only was capable of Mach 6 flight) also required lots of time consuming maintenance between flights, although of course not as much as the Shuttle. All this was probably mostly due to the laws of physics + engineering limitations, rather than the impact of bad government bureaucrats.
MARCU$
http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld037.htm
Marcus: Good to hear from you!
My major complaints are the 1000 mile cross range capability and the payload mass and bay sized to fit black satellites. Perhaps the original was also a bit too large, but it did not, as I remember it, have the wing loading of the eventual ship; nor was it as large overall. A 747 may be big, but I think a stacked STS on the pad might be a bit larger?
The original did not have tiles or need them AFAIR and it did not use solid rocket boosters (an abomination of an idea in my mind).
btw, haven’t the two of us been having this same argument for 20 years now? 🙂 🙂
Hi Dale.
My point is that one should be careful when playing these “what-if” games. The options that seemed
perfectly rational in the early 1970s may no longer seem very attractive with the benefit of hindsight. But the options rejected then may not automatically be “better” or “more realistic” than the Shuttle we got.
Regarding Maxime Faget’s TSTO Shuttle design, you will find the basic information on my website [ http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld022.htm ]. Let me highlight a few salient points:
-The expected development cost of this fully reusable design was $6 BILLION at early 1970s rates for a bare-bones system having a puny payload capability of 5.5t. Now, bear in mind that NASA had to promise a 29,5t payload capability to justify the Shuttle $5.15-billion price tag ….
-The risk of developing Faget’s fully reusable design would undoubtedly have been higher since we are talking about a system which is far more sensitive to weight growth, requires more lightweight structures, reusable cryogenic tankage etc.. Since it was fully reusable, the Faget “DC-3” TSTO vehicle would actually have been slightly BIGGER than the current Shuttle despite only having a puny payload capability!
-The high angle-of-attack reentry mode appeared problematic to most aerodynamics experts, who felt the straight wing would be dangerously unstable at hypersonic speeds and probably not feasible from a thermal protection point of view (Faget assumed silica tiles would be used, much like the current Shuttle [metallic TPS would be used on low temperature areas as well]). As far as I know, almost no other RLV proponent has advocated this particular reentry approach.
-The military disliked the low crossrange and marginal payload carrying capability. What is the point spending $6 billion on developing a high-risk space transportation system if there are no payloads?! (the 12-man space station was essentially cancelled in 1970).
The overall cost tradeoffs are summarized on my website as well — see
http://www.abo.fi/~mlindroo/SpaceLVs/Slides/sld037.htm
I don’t think it is easy to come up with a realistic “alternative” early 1970s space policy if the goal was to drastically reduce the cost of launching government payloads. I do believe NASA should have faced reality and reluctantly given up the Shuttle in 1971. Nixon’s Office of Management and Budget bureaucrats did promise a small Titan IIIM launched spaceplane dedicated exclusively to human spaceflight since nobody wanted to outright cancel the manned space program. NASA should have accepted the OMB proposal, particularly if the offer had included an “evolved expendable launch vehicle” booster for unmanned payloads as well. The US had already developed a fleet of excellent but expensive ELVs during the cold war space race; it would have been cheaper to try to transform the developed technologies into a (somewhat-) cheaper expendable launcher. NASA had solid fuel as well as pressure-fed “dumb” rockets on the drawing board; I think either option would have been better suited for unmanned ELVs. For manned missions, just put the “mini shuttle” on top. This is essentially what was being proposed in the year 2000 anyway… But it would not have produced the drastic launch cost savings NASA was aiming for with the Space Shuttle, and “better” is the enemy of “good enough” as well all know. Unfortunately, there’s also the issue of political “budget cut assurance” — if the US only has a single launch vehicle and if astronauts are required to fly it, the project will not be cancelled.
MARCU$
The 1024 x 32 bits reminds me of one of my most educational software experiences: Back in the 80s, I went to see an old, but still in service, military computer with something like 512 x 16 bits of code. After 30 years of continuous tinkering, the developers were still modifying it!
Good to hear from Marcus. He’s got some of my favorite pages on the web.
However, integral tanks are a boon to TPS. The X-33 is an example: the massive empty volume of tankage translates to lots of surface area ergo low wing loadings (counting the fuselage as lifting body), which is why X-33 could use titanium aluminide plating rather than silica bricks as the Shuttle requires. Of course, both X-33 and the original shuttle, like STS, are designes hampered by the fixation on LH2 as fuel. As a result, large tanks result in large drags. For the flyback stage, this drag is good in that it allows fast deceleration at high altitude before dynamic pressure has a chance to climb to a point that is too high for more moderate TPS to handle. Note that the MA-25 TPS used on the STS ET can handle up to 1200 degrees, totally sufficient for flyback at mach 10. The ET has to be reentered near orbital speed and sideways to get it to break up. If it had wings and broke off at mach 10 at above 250,000 ft, it could decelerate and fly back with the same MA-25 tps material. This was essentially the plan with the Shuttle II proposals.
High angle of attack reentry was not solely Faget’s plan. As I detailed in my article, the FIRST reentry glider would have reentered at 70 degrees AOA with a -1 degree glideslope. It pulled 2 g’s early on and lost lots of speed above 300k ft. This Aerojet project was extensively studied and based on an earlier project that flew a reentry inflated rogallo wing, which only failed because the nose fairing of the booster hung up on it. Even then, it flew quite stably until the added mass dragged it too deep too fast. James Oberg wrote a good article on this which I think I linked to in my article.
Dale: Here’s a link to the future scenarios: http://www.fas.org/spp/military/docops/usaf/2025/af/a-f-1.htm
Overzealous antispam filters….
Mike posted a comment here which I rcvd in my inbox but which does not seem to have appeared here. Since it was just a link I am presuming that was due to our new and as yet not totally undercontrol spam filters. So here it is:
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From Mike Luray
Here is a link to the original
http://www.park-ethereal.net/images/DSC_3522.png
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Now my question. Mike, what is the provenence of the photo? Is it purporting to be a B70 like aircraft? I definitely see the twin tails and two underslung jet engines when I blow it up. Give my a bit more info and I will be happy to publish my blow up.
I might add that there is nothing to give me scale so there are a number of possible aircraft. It could even be an SR71. Perhaps even a Tomcat or other fighter.
Not a blackbird, the tailfins are either paralle or angle out. blackbirds IIRC angle in. Also, I’ve lost my aircraft books but didn’t the blackbirds engines exhaust farther aft? Also, the tailfins have too high aspect ratio.
The thing darn near looks to have the horizontal proportions of a space reentry vehicle, I forget which one, but it looks flatter in the verticle dimension. And of course, has thrust.
Engines are far enough apart for a tomcat, but the wings/tailfins look all wrong.
MIg 29 w/o wings? 😉
It looks very Aurora ish to me. Whatever Aurora really looks like.
Also, I don’t have a picture, but I thought the blackbird tailfins came out of the engine housings. No?
Yup. Whatever that is, I seriously doubt it’s a blackbird- the tailfins on that cant inward, not outward.
Looks kind of like an F-15 with outrageously oversized tailfins.
I was basically throwing out suggestions hoping for others to come up with something. Perhaps it is the distance but the profile doesn’t really look like anything I am familiar with. It looks like two engines underslung with a bit of distance between them; looks like if it is a jet it is running afterburners; if it were any of the aircraft I suggested there would be wing beyond the spread of the twin tails, although a B70 has very thin wings and it is far away; the fuselage body looks a bit chunkier than most of the aircraft mentioned.
Does anyone else see what looks like a blended wing/body/lifting bodyish look to it? Or am I just letting fuzzy pixels run away with my imagination?
In the interests of completeness, I must also say my first impression was of a standard format airliner or cargo plane at an angle with the bright spots about where the port wing would be showing. The trouble is, I cannot with that view of things explain the bright spots. They would be totally wrong, as would the contrails which are spaced to narrowly to be wingtip vortices from a really heavy transport.
That left me with viewing them as the engine exhausts which puts them on the back and makes the protrusions twin tails instead of starboard wing and vertical stabilizer. From the replies I would guess everyone else came to the same conclusion.
Dale, I had exactly that same first impression and started wondering about jatos. The more I looked at it the less that was possible. It would be asymetrical.
I did find this(Link) of the Aurora which, ignoring engine config, is very compatible with the photograph. With that aircraft you could hang anything from jets to rockets to ramjets. Don’t think engine config will mean much, here.
The lifting body look is what made me think of the reentry vehicle. I forget which one.
Dale,
Okay, last time I paid any attention to performance aircraft the Hornet was still in final development and the SR-71 was considered pretty cool. (I still like it for pure cool) What is that? 25 or 30 years? Yeah. I’m catching up a bit. Never heard of Aurora before this thread. Mach 6, eh?
I doubt conventional afterburners, the flame isn’t right. And besides, why put sub hyper engines on a hyper craft? Unless they were a transitional power source for ramjets. Jetison a turbine engine? It’s possible I guess. But it doesn’t look right.
It’s burning very clean. Probably not solid fuel rockets.
Comments, really strange shaped flames. Does anybody know if that’s what a ramjet, pulse jet, or PDE plumes are supposed to look like?
I thought pulse jet flames looked a lot like afterburners. Long and segmented.
That weird burn shape is almost an argument for PDE. But that’s not supposed to really exist, is it? And no donuts. Are they always present?
Combined cycle ramjet?
Curious the picture is a bit map and not a jpeg. Its url filename suggests it was taken on a Sony? Why didn’t whoever leave it in its original format? Or did you reformat it? Is the original camera data available? Who took it? Where?
I think there appears to be something big hanging under the centerline. It doesn’t look (based on the profile of the port tailfin) that the tailfins extend below the wing. At least, not much. Yet something is below the fuselage. Has to be the engines I think.
It would be nice to know what the photographer thought the approximate speed range was.
Hey, Dale, thanks for putting that up. The photographer was in Davis, California, where he lives. The raw image is mostly sky, about 29 megs of data. I zoomed in on the acft. The original raw images are on the X-Plane.org forum where he posted details of the lenses, exposure, etc. There was similar lack of identification of it by folks there, too, though there was one bloke who thought it was a 737 in a bank, however that would require that the port wing be visible or the jet would have a dihedral of upwards of 30 degrees for it to be hidden by the fuselage (as would the horizontal stabs.) Candidates were the XB-70, Mig-25/31, and F-22, though while the F-22 would be the most likely candidate, the exhausts are too far apart and are not square as the Raptor has. Don’t know if any silicon valley thrillionaires own a Mig-25 or 31.
The photographer says it crossed the sky from horizon to horizon in about 12 seconds, the fastest thing he’d ever seen.
Some suspect (as I do) that it is the ABLV (Air Breathing Launch Vehicle), supposedly a classified development of the “flying plank” design seen in the original National Aerospace Plane and the X-43A. I’ve got a pdf of the ABLV proposals put out by Georgia Tech and it features two afterburning turbojet engines for sub-scramjet velocity travel which would be positioned comparably to this image.
By the way, the name is LORREY…. 😉 as in truck.
I did find this(Link) of the Aurora which
That’s a CG artist’s concept bluescreened onto a background. I’d take it with a shovelful of salt.