no matter how fast an aerial vehicle goes, it won't outrun the speed of light...so laser weapons could possibly knock it down. how long would it take to cross the visible sky on "flat ground"? the laser weapon would have to lock on to it and deliver it's punch before it leaves view. I'm just trying to be a devils advocate when it comes to military weapons. I'm certain that plans will be eventually stolen for the SR-72, but capability for mfg. those plans will take another 5 to 10 minimum. I wonder if the usa will ever be able to 3D print the components and auto-assemble them? Also, if the vehicle is un-manned; then how long will it take someone to hack the controls? would hate to have the SR72 attack us!

Pilotless.. what fun is that.

sr-72: unmanned - how boring!

This was my all time favorite plane growing up, I was fortunate to have seen it a few times in my life at air shows and Smithsonian. I even got to see it fly!, and that was something!, the SR-71 and the Space Shuttle first takeoff and landing was two of my best memories of aviation and space history in the making.

It might follow the SR-71 but - IMO - it would never truly replace it. I think the SR-71 is still the coolest.

"Leland explained that the retirement of the SR-71 left significant gaps in the satellites, subsonic manned and unmanned platforms meant to replace it, which the SR-72 will fill." Well of course he would say that - he is the Lockheed Martin program manager for Hypersonics. The only way he will get his program to float is to get the US Government (read US tax-payers) to fund it. I challenge him to elaborate on these "significant gaps". As much as I am a fan of the SR-71, it predated satellite, stealth, drone and internet intelligence surveillance methods and in it's day was the only viable way to rapidly gain specific critical information regarding the USA's international threats. Money aside, it looks good but somehow I suspect it will never fly (pun intended).

notarichman,
Surface-based laser weapons would have a hard time shooting down a plane at 80,000-100,000 feet, especially if it's not directly overhead, making the distance even longer. Seeing something and shooting it down are two different things. Between obstructions like clouds, atmospheric blooming, beam spreading and other phenomena, you'd be lucky to land 50 watts of energy on the SR-72, which would already be designed to withstand the extremely high temperatures encountered at hypersonic flight.
Australian,
Satellites have predictable orbits and limited fuel for maneuvering. It's not like the movies where someone can order an immediate repositioning for new shots of an area of interest. Drones have limited sensor suites, speed and range and are vulnerable to attack by any real air force. Internet monitoring doesn't help you at all for physical reconnaissance. For instance, Iran isn't going to go around transmitting the specs for its nuclear facilities for us to intercept, at least not without heavily encrypting it. Often, you just need an aircraft that can get to the target fast, shoot it with more than just cheap CCDs transmitting a few megabytes of images, and stay too high up to be shot down.

I'd feel more comfortable if this were a NASA program.

I have a question. When I read that it was going to be unmanned... my mind immediately thought of that debacle where Iran stole one of our recon drones, by jamming it and then sending it fake GPS coordinates to make it fly into their waiting arms. What's to stop someone from doing this now?

What about airborne refueling? Do we have an unmanned high speed tanker in the works? Slowing down from Mach 6 to Mach .3 every 30 minutes to refuel would be a hassle.