Gentlemen?,
The SR-71 is in my view one of the greatest engineering objects in history > of historic technology, engineering and implementation precision, and an unrivaled aesthetic in it's beauty of fearsomeness.
An important component in making the SR-71 was to replace the U-2 as being capable of flight high and fast enough to be immune to surface to air missiles. As we have seen with the failure of SDI, "Star Wars" systems, - and even the much lower than advertised success of the Patriot system- the difficulty of "shooting a bullet with a bullet", the SR-72 could have some relevant surveillance mission, and be survivable.
But there are a lot of problems.
That system would have to be in a state of constant deployment. Current scramjet systems like the X51A are launched from under B-52 wings and need a rocket stage to achieve the engine induction rates- and so far the longest flight time is under two minutes. A ground-launched system would be impossibly heavy. An X51a is about 1900kg (4,000lbs) The SR-72 image shown must be an altered attempt at corporate disinformation- the drag, engine placement and induction shapes ( you don't just cut the bottoms out of glued together recycling bins) and missing components- such as ISR components and missile mountings, the control surfaces size, wing aspect ratio and shape hardly rise to the design realism of sci-fi movie production design. If this system is to deliver missiles, where do they come out or off of? You're not going to open doors at Mach X. and the shape of the missiles would have to almost integral to the aircraft and also be hypersonic waveriders, i.e., you'd have to design the missiles as part of the aircraft and weaponry would have to be symmetrically deployed. The weight to power ratio needed to achieve the nominal acceleration rate to start the scram jet means that it could hardly have fuel for ten or so minutes flight- although you can go a long way in ten minutes at 5km per second- and the payload limitations would prohibit a manned system- it might have the capacity for a couple of stripped down camera-phones. On that subject, the state of ISR (Intelligence, Surveillance, and Reconnaissance) devices at the advertised speeds is not encouraging. Really, it seems to me that cruise missles should be as accurate and deliver a substantially greater payload. The article touches - but doesn't emphasize the extremity of thermal dissipation problems- think "Shuttle" in that degree. I, probably like most here, only occasionally work on hypersonic design, but even to the casual eye, the fluffy/draggy shape, with tall, deep vertical stabilizer and wide wings don't appear to me to represent serious consideration, or, more likely, simply have to hide the neat stuff. Still, if that rendering represents the state of the design, it's not going to be ready in 2018.
As this is a computer forum, I'd be interested to learn what visualization programs and computer systems Lockheed used. I'm guessing Sketchup 8 and Maxwell rendering on Dell Precision T3400's. Lockheed is welcome to come over to my house if they'd like to try Solidworks and V-Ray.
The other problem and this has been mentioned in other comments is what the SR-72 could really accomplish. The public doesn't know how many surveillance-capable satellites exist, the amazing resolution-day and night, and how surprisingly quickly they can be retargetted. NORAD satellites don't have as much to do as they did during the Cold War and perhaps they could be on loan for border security. As well,what satellites can't do, the popular drone systems do reasonably well, and wouldn't cost $3.5B each,...
By the way, note to dedicated gamers, Boeing is looking for trainee drone pilots!
I suspect that there are those in the DOD with great expectations of the SR-72 system use, and it could produce valuable technology for near-space systems, but unless the reveal is deliberately obfuscated, I'm not reading or seeing anything that suggests much seriousness. It is of course, no secret that to the degree they were serious, so to the same degree would they be secret.
Still, if Lockheed can be a bit more creative and gets it to work, the US would have an immensely impressively expensive and nearly useful status symbol.
But please, if the SR-72 is a multi-$Billion billboard, Lockheed, might at least give it some visual excitement. The SR-71 was an authentic work of art,...
BambiBoom
PS> Lockheed Reminiscences > I've poked fun a bit at them, but Lockheed is an amazing company, of historical significance, and I always follow their design. Along with everyone else, I stood around and gaped at the F-117 at it's first appearance at the Van Nuys air show. A very strange device. Surprising how small it seems compared to how amazingly large is an F-22.
For years my office was down the street from their big Calabasas, CA office complex, but then they downsize-shipped everyone off to I think Bethesda, and the ill-fated building turned into Countrywide until the mortgage detonation, and then again it became Bank of America corporate. I often wished I could've dropped in and seen what was on the boards, but I think that was corporate and the fun stuff was out of town at the Skunk Works- over which I once enjoyed a low level helicopter flight.