Posted on 03/28/2004 12:35:16 PM PST by BenLurkin
EDWARDS AFB - An experimental aircraft from NASA's Dryden Flight Research Center made aviation history Saturday when the unmanned X-43A hypersonic vehicle became the first non-rocket, air-breathing aircraft to fly more than seven times the speed of sound. "Today was a grand slam at the bottom of the 12th," X-43A project manager Joel Sitz said.
The successful flight was met with cheers in the Dryden control room and from those gathered to witness the historic event. Nearly three years ago, the first attempted flight of the X-43A ended in failure when the rocket booster went out of control.
"I think we saw the birth of a new propulsion system today," Sitz said.
The flight was a milestone as the first time a supersonic combustion ramjet - or scramjet - was successfully flown while integrated with an airframe.
"The ramjet, scramjet is the Holy Grail in aeronautics," Sitz said. "If you're going to go from ground to space, you need a scramjet to do it efficiently."
In Saturday's test, the vehicle's experimental scramjet engine successfully ran for slightly more than 10 seconds, providing data that researchers will use to validate the tools used to design and evaluate future scramjet engines.
"It's not often you're able to participate in a true milestone of flight," Dryden Center director Kevin Petersen said. "I think this will renew interest (in hypersonics) in the country. Once we prove the technology is viable, it should open avenues for added work."
Only 12 feet long and weighing approximately 3,000 pounds, the X-43A is shaped like a flat wedge with fins. The small research aircraft consists largely of the scramjet engine and supporting systems.
This scramjet engine was the experimental focus of the flight, part of NASA's $250 million Hyper-X program to investigate hypersonic flight.
To get the X-43A to the Mach 7 speeds necessary to test the scramjet engine, the research vehicle was propelled by a modified commercial Pegasus rocket booster. The X-43A is attached to the nose of the rocket booster via an adapter.
The entire 50-foot assembly, known collectively as "the stack," is carried aloft beneath the wing of NASA's workhorse B-52, the same carrier aircraft that launched the X-15 rocket planes.
After taking off from Edwards Air Force Base on Saturday afternoon, the bomber streamed contrails as it carried its payload to the test area over the Pacific Ocean, in the Naval Air Warfare Center Weapons Division Sea Range.
The stack dropped from the bomber at 2 p.m., at 38,900 feet and about 50 miles off the California coast. Within seconds, the rocket booster lit its engine and streaked through the clear blue sky, carrying the X-43A to approximately 95,000 feet and Mach 7.
Upon reaching the desired altitude, the launch vehicle successfully leveled off, a maneuver never before attempted with the rocket booster.
Upon reaching the intended altitude and speed, the X-43A successfully separated from the rocket booster, a feat that also had not been attempted before. Pyrotechnic rods within the adapter pushed the research vehicle away from the rocket, which then opened the inlet to the scramjet engine to begin scooping in air.
Judging by preliminary data, the experimental engine performed just as expected, producing positive acceleration.
"It's been an outstanding, record-breaking day," said Lawrence Huebner, X-43A scramjet lead with Langley Research Center, a second NASA center involved in the project. For a historical perspective, he compared it to the Wright Brothers' first flight, which totaled about 120 feet. In the same time span, the X-43A covered over 15 miles.
"What we demonstrated today is something we've seen working on the ground for 40 years," Huebner said. "Flight is reality."
"The big difference is that it wasn't just an engine we were flying," he said. "We were flying an engine wrapped in an airframe."
Following the engine test, researchers continued to collect data as the vehicle slowed and descended to an ocean splashdown approximately 450 miles offshore. Both the X-43A and Pegasus rocket booster were intended for one-time use and will not be retrieved.
Scramjets have an advantage over conventional rocket and turbojet engines in that they are more efficient. These air-breathing engines do not have to carry an oxidizer on board to mix with fuel, instead using oxygen scooped into the engine from the air. For space launch purposes, this means lighter launch vehicles with more payload capacity.
With Saturday's successful flight, a flight of a third X-43A is scheduled for next fall. This one, with slight modifications to the third and final vehicle, would travel to Mach 10.
During the first flight of the X-43A, in June 2001, the Pegasus rocket booster and X-43A went out of control before separating. The launch vehicle was deliberately destroyed by controllers, and both the rocket booster and research vehicle dropped into the ocean without completing the experiment.
The ensuing investigation found problems in the models used in predicting the vehicles' aerodynamic characteristics and the rocket's fin actuator system.
Modifications were made to the fins system, and propellant was removed from the rocket booster to allow a more typical Pegasus launch at 40,000 feet altitude.
The hype NASA generated for this test flight was appropriate based on what was achieved but I suspect their real interest, from a public relations perspective, is to generate funding beyond the next test which will use up the last X-43A. Savvy move by NASA, I don't think they'll have too much trouble finding money for the next phase of scramjet aircraft development.
Dumb question: orbital velocity is 17K mph and escape velocity is 25K mph. How is an air breathing engine going to be useful for anything other than sub-orbital flights (On the otherhand, I'll bet it'll help getting from home base to a target rich environment quickly) ??
Don't get me wrong, I think NASA has hit a another home run and I realize there is a lot we can do with scramjet engine technology, but how's it gonna help get into space?
1) The SCRAm is part of a multi-stage system with the final stage using its own oxidizer
or
2) The SCRAM intake are placed on the bottom of the craft and it cruises at the absolute highest altitude it can go, skimming along the top of the atmosphere. There it either delivers a payload back to earth (passengers NY to Tokyo in 90 minutes?) or it launches a space vehicle off its back and into orbit.
The NASA feed gave a good view of it under the wing of the B52.
"The ramjet, scramjet is the Holy Grail in aeronautics," Sitz said. "If you're going to go from ground to space, you need a scramjet to do it efficiently." Absolutely. This IS the next generation of truly reliable, routine space launch.
It sure did look small mounted on the booster rocket.
Ms. Gaitlin is not that technically savvy if she can write a misleading paragraph like this.
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