For a big chunk of the Cold War, the U.S. Air Force turned to the SR-71 Blackbird for many of its most important spy missions. The jet-black jet could fly at more than three times the speed of sound at altitudes of 85,000 feet, faster and higher than anything adversaries had to counter it.The last of the Blackbirds flew in 1999, and the U.S. military hasn't had anything close since.Now, Lockheed-Martin, the maker of the SR-71, says the "Son of the Blackbird," the SR-72, is in the works, and it will be twice as fast as and way more lethal than its father. That's because the SR-72 will be designed to launch missiles, something the SR-71 didn't do."Even with the SR-71, at Mach 3, there was still time to notify that the plane was coming, but at Mach 6, there is no reaction time to hide a mobile target," Brad Leland, Lockheed Martin's program manager for hypersonics, told Aviation Week and Space Technology. The publication provided the first detailed look at the SR-72 plans last week."Hypersonic aircraft, coupled with hypersonic missiles, could penetrate denied airspace and strike at nearly any location across a continent in less than an hour," Leland said in a news release.And, by the way, the SR-72 is envisioned as a drone, unlike the original Blackbird with its crew of two: a pilot and a reconnaissance officer to operate its radar jammers and spy gear."The SR-71 was developed using 20th-century technology. It was envisioned with slide rules and paper. It wasn't managed by millions of lines of software code. And it wasn't powered by computer chips. All that changes with the SR-72," Lockheed Martin says.A smaller-scale model of the SR-72 could begin testing in five years and be in the air in 10, Leland told Aviation Week.The full-scale SR-72 could be operational by 2030, according to Lockheed Martin.If it comes to fruition, one thing the SR-72 won't be is stealthy. The design needed for the Mach 6 speed doesn't allow for such construction, according to the Aviation Week report."Speed is the new stealth," Aviation Week quoted Al Romig, engineering and advanced systems vice president at Lockheed Martin's Skunk Works division, as saying."Speed is the next aviation advancement to counter emerging threats in the next several decades. The technology would be a game-changer in theater, similar to how stealth is changing the battle space today," Leland said in the statement.Of course, none of this will fly without money, and that will probably be up to taxpayers."We have been continuing to invest company funds, and we are kind of at a point where the next steps would require large-scale testing, which would significantly increase the level of investment we've had to make to-date," Leland told Aviation Week. "Between DARPA (Defense Advanced Products Research Agency) and the Air Force, it would be highly likely they'd have to fund the next steps."(CNN)ANN.Az