The new Sänger space transportation system concept conceived by MBB in 1985 is aiming for essentially reduced launch cost (10-30% of Ariane/Hermes) and full European autonomy by launches from European airports with direct access to the Space Station orbit (LEO,28.5°) These requirements lead to a two-stage system with a hypersonic first stage using turboramjet propulsion providing the required cruise capability of some 3500km The cruise speed is Mach4.4 with the capability to accelerate to Mach6.8 before separation of the upperstage Two different upper stages are foreseen for the different requirements of manned spaceflight and unmanned payload transportation a winged manned stage for crew transport and support equipment (HORUS) and an expendable ballistic stage for launch of heavy payloads up to 15 Mg (CARGUS) The Sanger concept is based on maximum commonality of the first stage with a hypersonic passenger aircraft, carrying 230 passengers (business class) over a distance of 10,500km in 3h The paper describes the resulting vehicle configuration ,the performance criteria, the technology problems to be solved and the overall programme schedule for the incorporation into the European Space program
One question in my mind is whether the project would have succeeded if the money/budget would not have been needed for re-unification of Germany? The initial projection was Germany needed $100bn for a 30 year plan to reunify. The other thing I wonder about is technology. When you look at NASP, HOTOL for comparisons, was Sänger 2 technically feasible in 1990? Or were there unsurmountable technical issues down the line?
The other thing I wonder about is technology. When you look at NASP, HOTOL for comparisons, was Sänger 2 technically feasible in 1990? Or were there unsurmountable technical issues down the line?
QuoteThe other thing I wonder about is technology. When you look at NASP, HOTOL for comparisons, was Sänger 2 technically feasible in 1990? Or were there unsurmountable technical issues down the line?The two major difficulties were -the Mach 6 first stage: thermal and propulsion nightmare;-separation of stage 2 at hypersonics velocity. -NASP was essentially a fraud, courtesy of everybody at DARPA drinking Tony Dupont koolaid (as Congress did in the next two decades with the fraudulent DP-2 VSTOL). Scramjet airbreathing to Mach 25 & orbit - yeah, sure, dude. -HOTOL had two major issues: RB-545 cycle and CoG issues. That's why they shifted to Skylon thereafters.
QuoteThe other thing I wonder about is technology. When you look at NASP, HOTOL for comparisons, was Sänger 2 technically feasible in 1990? Or were there unsurmountable technical issues down the line?The two major difficulties were -the Mach 6 first stage: thermal and propulsion nightmare;-separation of stage 2 at hypersonics velocity.
-NASP was essentially a fraud, courtesy of everybody at DARPA drinking Tony Dupont koolaid (as Congress did in the next two decades with the fraudulent DP-2 VSTOL). Scramjet airbreathing to Mach 25 & orbit - yeah, sure, dude.
-HOTOL had two major issues: RB-545 cycle and CoG issues. That's why they shifted to Skylon thereafters.
Quote from: Spiceman on 07/08/2024 03:38 pm-NASP was essentially a fraud, courtesy of everybody at DARPA drinking Tony Dupont koolaid (as Congress did in the next two decades with the fraudulent DP-2 VSTOL). Scramjet airbreathing to Mach 25 & orbit - yeah, sure, dude. I read the "Hypersonic revolution" just like you.
In addition, about Sänger, there was the whole operational aspect of it. See attachment below. Launching from Europe to land in Africa does not sound feasible these days. Politics I wonder whether they could have launched from Kourou, still get into the correct orbit for the ISS, and maybe landed in Spain. In the attachment, Spain was mentioned as a potential launch site which is why that seems reasonable.
My opinion of Tony Dupont is based on Richard P. Hallion "the hypersonic revolution". Also the X-15 HRE (podded scramjet = a very bad idea) before it, and the DP-2 after it. https://en.wikipedia.org/wiki/DuPont_Aerospace_DP-1
He really grossly oversold the idea to DARPA (COPPER CANYON), and they drank the koolaid. And everybody drank the koolaid afterwards, up to Reagan and his "Orient Express".
I always recommend Heppelheimers "Surviving The Heat Barrier," which shows the context of before and after NASP.
Quote from: john smith 19 on 07/12/2024 09:42 amI always recommend Heppelheimers "Surviving The Heat Barrier," which shows the context of before and after NASP. This book, "Facing the Heat Barrier" yes ? https://www.nasa.gov/wp-content/uploads/2023/04/sp-4232.pdfThanks for the tip, looks excellent. And also looks as if there's a lot of perennially difficult science (like turbulence) in the story, as well as what HAL 9000 would call "human error" ;-) (or optimism, fraud, whatever). And thanks all for your enlightening posts.
Quote from: LittleBird on 07/12/2024 03:02 pmQuote from: john smith 19 on 07/12/2024 09:42 amI always recommend Heppelheimers "Surviving The Heat Barrier," which shows the context of before and after NASP. This book, "Facing the Heat Barrier" yes ? https://www.nasa.gov/wp-content/uploads/2023/04/sp-4232.pdfThanks for the tip, looks excellent. And also looks as if there's a lot of perennially difficult science (like turbulence) in the story, as well as what HAL 9000 would call "human error" ;-) (or optimism, fraud, whatever). And thanks all for your enlightening posts.Yes that's the one. It's also got ASCENT and PRIME as well as the X-15 and Shuttle. It's also quite good on some of the characters involved (and reading between the lines some of them were real "characters" not too far off DuPont). Some of the more detailed stuff is in the Defence Science Board reports which I read but can't recall cites for.
In any project of this kind there are several factors that can seriously stuff you. Example. The ability to pin down the point on the vehicle where laminar flow goes turbulent (and increasing heat transfer to the vehicle between 3x and 10x) can change how much TPS you need. That (in the case of NASP) could change GTOW 2x. IOW 100% increase in GTOW. It's true individual processor speed has grown about 3000x since 1970 and memory about 10000x fold (1MB was a DEC mainframe. 1GB is a phone), but AIUI the theory has not radically improved. Essentially the SW still has a bunch of "knobs" that you twiddle to get the "right" result and an experienced CFD person can converge on a working design faster than a newbie. Yes you can build bigger, more detailed models in the same amount of run-time, but will they be any more accurate?This is not the sign of process that is well understood.
I didn't realise until relatively recently that is why Skylon is the shape it is. It is in fact a Sears-Haake body, which theoretically has the lowest wave drag in supersonic flow. A case of avoiding the problem in the first place rather than coming up with some super-duper clever solution that might be more compact but which might not actually work
The Sears-Haack body https://en.wikipedia.org/wiki/Sears–Haack_body seems to be the result of a linear theory (Karman-Moore) from 1932 [*]. Has it been tested in practice at hypersonic speeds on other vehicles ? [* By the way I am not in any way knocking such theory, any more than I would K41 scaling-I am just curious to know how well it works.]
my visit to Aachen University library ended mostly in a disaster !The Aerospace faculty has DESTROY THERE ENITRE LIBRARYthe Personell annoyed by my request and visit.were unable to tell me what happen to ELAC / EOS documents and models
