X-43 type program reemerging?

[nacnud]

Perhaps these images will help Scott.

 

[mlorrey]

wdobner is right on. Ramjets and scramjets are NOT complicated: far fewer moving parts than any other propulsion system out there. A cynic would say that rocket engineers avoid them because they are too simple: it means a reduction in R&D man-hours needed and thus goes against job security. Even engineers at any of the big aerospace firms are all union members. Afterburners are fine in order to reach military contract specs, but the idea of a ramjet as the primary propulsion system threatens the standing army of donut grazers.

 

[jschaef5]

Yah but don't ramjet/scramjet bring in whole new issues like heat shielding and higher stresses? <div class="Discussion_UserSignature"> </div>

 

[mlorrey]

Use of materials like C-C, metalic matrix composites, and active cooling are sufficient. MIPCC is sufficient to expand the flight regime of ramjets up to mach 8 with conventional materials.<br /><br />Ramjet propelled missiles have accelerated on their own from mach 1 up to mach 5.5. Useful thrust? How about 20 lbs of thrust per square inch of ramjet combustion chamber cross sectional area? How about thrust to weight ratios of 50 or higher?

 

[john_316]

Forgive me if I am wrong folks but would the X-30 NASP actually make a better shuttle than the shuttle if these key technologies are actually studied, tested, improved upon and redone over and over until we get it right?<br /><br />I mean I can see the next LEO space vehicle being a SSTO scramjet/ramjet X-30 NASP...<br /><br /><img src="/images/icons/smile.gif" /><br />

 

[wdobner]

<i>Forgive me if I am wrong folks but would the X-30 NASP actually make a better shuttle than the shuttle if these key technologies are actually studied, tested, improved upon and redone over and over until we get it right? <br /><br />I mean I can see the next LEO space vehicle being a SSTO scramjet/ramjet X-30 NASP... </i><br /><br />I think you just hit the crux of the argument here. There are some, myself included who see NASA or DARPA research into scramjets and hypersonic vehicles as being a crucial technology toward creating launch system which makes good on all the promise the shuttle offered but was unable to give. There are others, who I would suggest may be a bit jaded from years of disappointment, who would like to see that money go toward what they view as more deserving projects, i.e moon landings. Those folks probably would be more than happy to see NASA continually shell out for expendibles to put some footprints on the Moon or Mars while private companies develop a cheaper launch system. Before this runs off into another argument on the long term goals of our spaceflight program I will readily admit that some of the 'flags and footprints' advocates make a very valid point that NASA's spaceflight program for the past three decades has been woefully myopic. This would lead to what I believe is their second problem with a NASP type program, and that is precisely that it will create another shuttle. We'll go ahead and spend the billions to develop the NASP with all the promise that it holds, and then that will be all we'll do. For whatever reason either the development program will cost too much or the operational costs will be far in advance of what is currently projected and we won't have any money for what they (and the current administration) see as the important part of spaceflight, exploring the (inner) solar system and putting men on Mars. Given the almost total failure of the Shuttle to achieve it's stated goals this fear is somewhat justif

 

[vt_hokie]

Very well said, wdobner!

 

[mlorrey]

"Was the GTX the SSTO design that NASA wanted to launch using a Maglev track? "<br /><br />No. You are thinking of Spaceliner 2000. GTX is a proof-of-concept RLV SSTO VTHL that would have put about 600 lbs of payload in orbit based on its design. I'm not totally in love with it, actually, as it suffers from NASAs unhealthy fixation upon LH2, its payload would be much larger if it used a denser fuel like RP-1, methylacetylene, quadricyclane, cyclopropane, etc. while its airframe would be smaller (and its propulsion T/W ratio would be better too). However it would have been a true SSTO airbreathing hypersonic RLV and designed for the mission (none of this STS crap with aluminum airframes).<br /><br />They also proposed a 1/3 scale suborbital version of the GTX that would have taken off with the assistance of some Black Brants to reach ramjet speed and test the ram-ejector mode of the engines while under assisted thrust. This would have flown roughly the X-33 flight regime on a few hundred pounds of LH2 (like the X-43A, the scale version would be mostly processors and sensors, not fuel tank, and not intended to have the fuel capacity to reach orbit) and would have been built by NASA's cost estimates for $275 million. If accurate to NASA costing standards, this means that Burt Rutan could build it for under $15 million... <img src="/images/icons/wink.gif" />

 

[nacnud]

Does DARPA know about this <img src="/images/icons/wink.gif" /> , sounds great for a Falcon type vehicle.