Time to Revisit the Aerospace Plane Concept in Light of this Disaster

I worked on the X-30 project at General Dynamics in Fort Worth. Slush hydrogen was used to get better fuel density. Other things were used for oxidizor (classified then, maybe now) The X-30 was a materials marvel, it could fly through the heat of a volcano. There were rockets at Mach 17+ due to push to space, no air. The problem was the size. Too heavy. Never could get it down. I can't remember the exact fuel eater. We have materials that can take re-entry heat that have structural strength. NASP was made of it.

Well, now its 12 hours after the tragedy so anything goes, but at 9:45 am PST, before the deaths were even confirmed, anything but reverence seemed a bit much.

hydrogen slush fuel

If liquid hydrogen is further cooled (almost to the solidification point) it would form a slush. You wouldn't want to cool it any further otherwise you would have solid hydrogen - that stuff would be hard to pump.

Right. That is what I said, wasn't it? When I said "frozen," I meant like a slurpee is "frozen," but not, obviously, solid ice.

Exactly, but in this case it is even worse. By having the GOVERNMENT continue to subsidize the "1950s car technology," we are blocking or, at the very least, not funding, 21st century technology. There should have been a cut off on all Shuttle development, improvement, etc., and a new system begun years ago.

It's not necessarily true that SSTO won't work "because they quit trying." Many ideas need "vicinities" effects to work. For ex., the internal combustion engine was invented before Henry Ford, and even Ford's cars really didn't transform transportation until several things were in place: good rubber for tires; glass; a critical mass of car owners who demanded better (or any!) roads; Kettering's automatic starter; cheap gas (thank you, Mr. Rockefeller); and a host of other technological innovations that made a car worth OWNING. The same is true with scrams and SSTO: the challenges were so great that NASP had to master all at once. I think the program did a whale of a job getting the materials, the computational fluid dynamics (itself a remarkable breakthrough) and the slush hydrogen. Yes, the engine is key. But few engineers I've talked to think it is impossible---just that they haven't quite hit on the best way of doing it yet.

I think SSTO is the ONLY solution to space travel of any sort. Otherwise, there will never be a true "space station" of the "2001" type built.

I didn't say It's not necessarily true that SSTO won't work "because they quit trying.".

My thinking is they (Gov't programs) are incompetent to make it work. Gov't programs can not change gears fast enough to complete the engineering before funding runs out, and we exchange engineering for funding pursuit. When engineering takes a backseat to marketing, there's plenty of opportunity for Feynman's observation about successful technology to creep in:
For a successful technology, reality must take precedence over public relations, for Nature can not be fooled.

SSTO is very hard. The mass ratio is a killer, because after you add the return systems your payload fraction goes to nil. Given, of course, 1990's engineered materials. NASP is an application of the first obvious, air for oxidizer to improve mass ratio. Scramjet and ramjet engines have an extraordinarily high thrust to weight ratio (I've seen claims of 1000:1 for ramjets). But the physics of flying at high speed in atmosphere conspire to create a huge ding in the mass ratio again. It's not a linear relation.It's not optimal for all missions. It's not a one-size-fits-all.

I don't think FR is an adequate debating forum for this, perusing old USENET archives and AIAA papers I can see ample evidence of brighter lights at work on the physics and engineering. If the FEDGOV is going to spend gigabucks on this process I wish they would do it in a way which leverages the efficiencies of capitalism. I will admit I am a fan of TSTO (two stages to orbit). Considering the cost of materials on orbit, I would rather build a space station from discarded rocket boosters than pay to haul them back and forth from orbit over and over again. Lightweight return modules (namely capsules with heat shields) have a plenty good record.

There needs to be an financial incentive to get this going. If we feel it's proper to do as a nation, for Constitutionally supported purposes, then the appropriate thing is for the FEDGOV to get out there and emit the proper perverse incentive, i.e. pay for pound delivered to orbit, pay for person delivered to orbit, pay for surveys, prizes for research and development, etc. Not do the whole enchilada inhouse.

We fully agree on the difficulty. I think NASP was an exceptional program in TRYING to privatize this as much as possible. It basically set up a cartel of half the airfram manufacturers in the U.S. (and Grumman really had no shot to begin with, and Boeing wasn't that interested); and of 2/3s of the propulsion contractors. So they tried to get a "consortium" or cartel of everyone. Then the government backed off a great deal, allowing the contractors to meet the mission requirements.

One of the problems from the get-go was that this was supposed to be an X program, meaning a test program to measure things. But to get the AF to sign on, they had to demonstrate a payload bay door. That added thousands of pounds of weight. A 50,000 design ballooned to 500,000, and that was too big. Most of the experts---private and government alike---think they can beat the thrust over drag at lower weights.