An unmanned experimental jet broke a world record for speed on Tuesday, cruising over the Pacific Ocean at just under 7,000 mph (11,000 kilometers per hour) in a NASA test of cutting-edge “scramjet” engine technology.
The X-43A aircraft flew at a speed of around Mach 9.6 — nearly 10 times the speed of sound — after a booster rocket took it to around 110,000 feet (33.5 kilometers) and then separated.
A modified B-52 airplane had carried the experimental plane and its booster aloft.
It was the last of three test launches for the X-43A series and its supersonic-combustion ramjet or “scramjet” engine. The scramjet scoops up oxygen from the air rather than carrying liquid oxygen in a tank like an ordinary rocket.
Scramjet technology, NASA has said, could open the way to cheaper, safer and faster flights into the upper atmosphere, with smaller and lighter craft.
“I think it’s easier than people think it is. We can really do this stuff. I don’t mean to make it sound too easy, but it’s definitely doable,” Randy Voland, a senior research engineer on the project, said at a news conference after the test.
The eight-year, $230 million program got off to a rough start in June 2001 when the first X-43A and its booster rocket had to be destroyed in midflight. The second attempt, in March of this year, successfully reached a speed of Mach 7.
That Mach 7 flight set the previous world record for a jet-powered vehicle, NASA said.
The silvery-black scramjet, just 12 feet (3.65 meters) long by 5 feet (8 meters) wide, took off from Edwards Air Force Base in the desert north of Los Angeles early Tuesday afternoon, perched below NASA’s B-52 research plane.
After reaching launch altitude over the Pacific, the modified bomber dropped the scramjet and its booster rocket for a run at the speed record.
NASA video images showed the scramjet rising sharply, powered by the booster rocket. The booster separated at about 110,000 feet, and the scramjet kicked in. After a few seconds, the X-43A entered a glide, quickly losing speed toward a crash landing into the ocean following a total journey of around 800 miles (1,280 kilometers).
Along the way, the scramjet encountered temperatures estimated at about 3,000 degrees Fahrenheit (1,650 degrees Celsius), roughly one-third hotter than the test in March that reached Mach 7.
Engineers said the scramjet cruised after the separation, neither gaining nor losing speed during its operation. The 20 seconds of operation, they said, gave them far more research than they have had before on jet functions at those speeds.
“We have quite a lot to look at for quite a long time to come,” said Laurie Marshall, chief engineer on the flight. NASA and the Pentagon plan to assess the scramjet's potential for a variety of applications — ranging from more efficient spacecraft to hypersonic cruise missiles, to transport aircraft that could fly between America and Australia in as little as two hours.
The flight on Tuesday had been delayed from the previous day owing to electronics problems. NASA said it had no plans to recover Tuesday's test craft. Instead, the remains sank into the Pacific, in accordance with standard procedure for the scramjet tests.