quasi in rem

Sunday, March 28, 2004

This settles it, the Televised Media are officially idiots.
All day stations have been reporting on the 5X speed of soud level set by the NASA rocket. Unfortunately that is not the story. Not really.

The story is that they used a scramjet and they achieved orbital velocity. Here is apicture of the engine designs. "The test, conducted off the southern California coast, marked the first time that a 'scramjet,' or supersonic-combustion ramjet, has powered a vehicle at such high speed. "

The reason it is so cool is that the jet used oxygen available in the atmosphere as an oxidizer for hydrogen fuel. By using oxygen available in the atmosphere, the weights of craft seeking to escape the bonds of earth can be dramatically reduced. Currently the space shuttle is approximately 2/3s oxidizer by weight. All this weight can be eliminated for a ramjet thereby significantly reducing the cost to send things into space.
the shuttle requires acceleration at around Mach 25 to escape earth.

Ramjets operate by using their own velocity to force air into thier "engines". The real problem with all Ramjets is the basic PV=nRT problem of seriously increased temperatures as the pressure of the incoming increases. Former ramjet aircaft, like the Blackbird only achieved Mach 2.5 or so.

Not true anymore...

The unpiloted X-43A made an 11-second powered flight Saturday and then went through some twists and turns during a six-minute glide before it plunged into the ocean.

"It was fun all the way to Mach 7," said Joel Sitz, project manager at NASA's Dryden Flight Research Center. "Today we were successful at separating not only the launch vehicle from the research vehicle, but the real from the imagined."

"Flight engineer Lawrence Huebner said preliminary data indicated the X-43A reached a maximum speed of "slightly over Mach 7," or about 5,000 mph. It had been boosted to about 3,500 mph by a rocket, but he said no "air-breathing" jets had ever before reached Mach 7, seven times the speed of sound."

And here is the description of the flight itself...

"The 12-foot, 2,800-pound X-43A was mounted on a Pegasus rocket booster, which was attached under the right wing of a B-52 bomber that took off from Edwards Air Force Base in the high desert.

A minute before 2 p.m., the craft was dropped from 40,000 feet. A few seconds later, the rocket flared, boosting the jet skyward on a streak of flame and light. At about 100,000 feet, the rocket was dropped away.

The scramjet then took over, using up about two pounds of gaseous hydrogen fuel before it glided and then plunged into the Pacific Ocean about 400 miles off the California coast.

The vehicle's performance prompted a round of applause at the Dryden control center."

Only 2 pounds of fuel... too cool.

For more information NASA's Dryden Flight Research Center: http://www.dfrc.nasa.gov/


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