tag:blogger.com,1999:blog-2675974463524895416.post4215324553433399238..comments2024-03-28T10:26:00.255-05:00Comments on An Ex Rocket Man's Take On It: Third X-51A Scramjet Test Not SuccessfulGary Johnsonhttp://www.blogger.com/profile/06723964751681093047noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-2675974463524895416.post-38346331568857904842013-01-17T00:45:51.482-06:002013-01-17T00:45:51.482-06:00Randy
The risk of mis-identification is very high...Randy<br /><br />The risk of mis-identification is very high, yes. Mitigating this is that there is one reentering object (shround containing missiles), not a cloud of warheads and decoys. Plus, everybody tracking it can see where it's going (so exactly where you send it is a very important pre-launch decision). <br /><br />I'd think the Russians and the Chinese could tell that one aimed into the sea just east of N Korea is not really aimed at either of them. But, you're right, there is huge risk in using such a weapon. <br /><br />I think scramjet might make sense in a tactical missile role, such as USN's anti-anti-ship missile problem, which has been insoluble since the advent of the Kh-31 long ago. Sunburn and Yakhonts are the current huge threats to ships. No defense for them exists. <br /><br />GW<br /><br />Gary Johnsonhttps://www.blogger.com/profile/06723964751681093047noreply@blogger.comtag:blogger.com,1999:blog-2675974463524895416.post-17475196385923841662013-01-16T21:32:13.733-06:002013-01-16T21:32:13.733-06:00Gary;
The biggest "issue" with this ide...Gary;<br /><br />The biggest "issue" with this idea is the same one every "ballistic" delivery system (including specifically any of the "conventional" ICBM concepts) has:<br /><br />There is a great difficulty in telling one of these from one carrying an nuclear weapon. For the most part there are SOME "clues" in the trajectory but those don't appear until very late in the flight and by that time you've already passed the point where you have to make the decision to retaliate or not.<br /><br />Sure it COULD be exactly what "they" (people who launched it) is, but are you ready to take the chance that it ISN'T and find out too late it is the first action of a preemptive strike?<br />The "smart" answer is no...<br /><br />Scramjets have always seemed to me to be an answer looking for a question since they really DON'T help a lot with fast international transport, (same issues you've mentioned regarding staying in the atmosphere for long periods of time at high speed) or space launch. Nice to have for quick, super-long distance all-most invulnerable strikes of course, but inevitably you are going to run into the same problem as a "ballistic" strike: It could still have a nuke on it and be aimed at YOU so what do you do when it comes over the horizon?<br /><br />RandyRanulfChttps://www.blogger.com/profile/06405651956446782986noreply@blogger.comtag:blogger.com,1999:blog-2675974463524895416.post-27440258801333785022012-08-18T18:26:10.148-05:002012-08-18T18:26:10.148-05:00jstults:
Thanks for the comment. I really do app...jstults:<br /><br />Thanks for the comment. I really do appreciate it when people comment or rate the things I have posted.<br /><br />With some commercial launchers near $2500/lb at max load right now, and $1000/lb soon with the Spacex Falcon-Heavy, I think a revisit of the all-solid ICBM might show very low costs to do exoatmospheric transfer around the globe in scant minutes. <br /><br />Re-entry from barely-suborbital speeds is not that hard anymore. A shroud around the payload made of silica-phenolic ablater and some internal metal structure ought to be really cheap. <br /><br />Depending upon the size of launcher, there is room for a lot of supersonic plain ramjet cruise missiles as payload. And you do not need a booster, just shed the shroud and light the ramjet between Mach 2 and Mach 3, after entry is over. <br /><br />ASALM's launch weight was 2500 pounds, and that included about 700 pounds of booster propellant, and an ejectable booster nozzle, and an inlet port cover, none of which would be needed in the scenario I envision. So we're looking at slightly under 1 metric ton of ramjet to be rocketed to the other side of the world, per supersonic cruise missile. ASALM was to carry either 1000-pound conventional or nuclear warheads. <br /><br />Atlas-V-552 launches 25 metric tons, and Falcon-9 10-13 metric tons, depending upon which engine, all the way to orbit, both at $2500/lb. So, those are capable of sending 10 to 25 ASALM-class vehicles in a single shot anywhere in the world in under 20 minutes. <br /><br />Even the little Falcon-1 sends 1 metric ton to orbit rather cheaply. <br /><br />I think this mode would be rather hard to beat, considering just how difficult and expensive it is to treat the friction heating, and just overcoming drag to cruise, at hypersonic speeds in the atmosphere.<br /><br />GW<br /><br /> Gary Johnsonhttps://www.blogger.com/profile/06723964751681093047noreply@blogger.comtag:blogger.com,1999:blog-2675974463524895416.post-67558119856893799912012-08-18T11:29:26.516-05:002012-08-18T11:29:26.516-05:00Thanks for the info on ASALM-PTV; that's inter...Thanks for the info on ASALM-PTV; that's interesting.<br /><br />I think you are mixing two different use cases. There is a useful capability to be had from a fast cruise missile that tactical aircraft can employ, and there is a useful capability to be had in something that can be launched from the US and strike anywhere in the world quickly. The per round cost of these two capabilities should be drastically different.<br /><br />Yes it's tough to beat the efficiency of a nice high parabola, but shock or viscous losses are certainly tradeable against other requirements. Joshua Stultshttps://www.blogger.com/profile/03506970399027046387noreply@blogger.com