Rattlrs Strikes Fast

Cruise missiles are about to get a lot more lethal, thanks to a Navy program called Revolutionary Approach to Time-Critical Long-Range Strike, or Rattlrs. Lockheed Martin and Rolls-Royce North America have a $120-million contract to build a hypersonic missile demonstrator "with trace-ability to an eventual tactical weapon," says Craig Johnston, the Lockheed Martin program manager. First flight is slated for November 2007.
Older cruise missiles such as the Navy's sea-launched Tomahawk and the Air Force's Air-Launched Cruise Missile putter along at subsonic speeds, too slow to hit fleeting targets such as terrorist convoys. Rattlrs, by contrast, is a "near hypersonic" vehicle capable of speeds up to Mach 4. The demonstrator is aiming for a five- to 15-minute flight time. "To put that in perspective, that's on the order of a 500-mile range," Johnston says. The production version might have even longer legs.
But getting to that level of capability won't be easy.
"The challenge is to fit all of the required techs -- engine, flow-path, airframe, avionics -- into a package that is the size of a cruise missile," Johnston says.
Mach 4 speed normally requires a two-stage vehicle with a scramjet second stage. But Rattlrs is aiming for a single-stage turbine engine in order to keep the vehicle small. That means some creative engineering and materials science.
"Temperature is what drives efficiency in turbine engines," says Bob Grude, the Rolls-Royce manager. "We have some special techniques using materials called 'LAM alloys' [as well as] existing high-temperature materials, with a cooling system that allows us to operate the burner at much higher temps than normal."
Affordability is one of Rattlrs' goals, according to Johnston. "The objective on Rattlrs is an integrated system that pulls all same elements of current cruise missiles at greater than three times the speed with no premium -- to put it all into the same cost. Much of tech that is being developed, specifically in the engine area, is a careful balance between a maximum degree of expendability and [adaptability] for reusable vehicles that want to have a long lifetime."
In other words, Rattlrs won't just produce a better cruise missile; it'll feed tech into other hypersonics programs too. "We're in a sense enabling the turbine side of an eventual hypersonic solution [to several problems]," Johnston says.
Rattlrs is just one in a billion-dollar portfolio of hypersonics programs that, in the next 20 years, might revolutionize air combat, commercial air travel and space ops. The most dramatic outgrowth of these programs is the Marine Corps' squad space transport. Much more on that and other hypersonics programs later ...
-- David Axe