Engineers at NASA have created a prototype of an electromagnetic propulsion system that would use a linear motor and ramjet engine boost system--instead of an all rocket propulsion system--to fling a vehicle into space. It is the first system that would operate beyond the sound barrier using the combination of an air-breathing ramjet engine and an electromagnetic catapult. The work was presented this week at the Space 2009 Conference in Pasadena, CA.

The system is an alternative to traditionally-used chemical propulsion, which requires large amounts of fuel that limits cargo capacity. It is also a zero-emission, reusable system. The idea of electromagnetic launch using linear motors has been around since 1946, but it was not until the late 1990s that NASA started seriously investigating the idea.

The electromagnetic system works by tethering a spacecraft to a rail or track and using a linear motor to accelerate it to supersonic speeds.

"Linear motors are basically electric motors unwound," says Kurt Kloesel, an engineer in aeronautics and propulsion and lead researcher of the system at Dryden Flight Research Center, in Edwards, CA. "There are two groups of coils and an aluminum plate goes inside the gap [between the coils], when you hit the juice you are energizing the coils and the inductive reaction of that throws the aluminum plate out of this motor. "

"You are essentially propelling this vehicle along a track up to the point is disengages from the track and takes off," says Michael Wright, flight systems integration and test manager of exploration systems and co-principal investigator of the system at Goddard Space Flight Center, in Greenbelt, MD.

Kloesel explains that, as a vehicle starts to pick up speed, it incurs drag: "As you go faster and faster, getting towards the speed of sound, the drag goes up significantly, creating this shock wave structure on the vehicle. And once you pass the supersonic barrier the drag goes down again."

So what the researchers are proposing, says Kloesel, is using the electromagnetic system to get past the supersonic barrier. Then, the air-breathing ramjet engine--which feeds on incoming air at very high speed--would take the vehicle out of Earth's atmosphere. The ramjet engine would not be on the rail, but part of the vehicle itself.

The researchers have tested the concept in lab experiments with "bench top models", which have reached approximately 156 miles per hour. Wright says the technology might even be used someday on highway vehicles and airplanes.

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irjsiq

44 Comments

• 877 Days Ago
• 09/21/2009

Slingshot into Space

'Rail Guns' as 'Space Launches' utilizing 'Aluminum Coils' very prudent vs 'Rare Earth'
Magnets, as used in 'Mag-Lev' vehicles . . .
I have pondered such use for capturing slight
breeze wind power, or storing excess wind power, for inertia wheel storage . . . at a preset charge-level,
the 'rail gun' charge would transfer to the inertia wheel, which could also be utilized for Air Compression, which seems to be gaining favor for low wind days.

Thanks for the Article!

Roy Stewart,
Phoenix AZ

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Mapou

357 Comments

• 877 Days Ago
• 09/21/2009

Interesting But...

The idea of electromagnetic launch using linear motors has been around since 1946, but it was not until the late 1990s that NASA started seriously investigating the idea.

Wow. 1946, eh? I don't know about other readers but I find all current and proposed space transportation technologies (magnetic slingshots, space elevators, rockets, solar sails, ram jets, ion propulsion, nuclear propulsion, etc.) to be excruciatingly primitive, almost laughable even. It's kind of like riding to town on a major ten-lane highway in an ox-driven cart. I realize that all that stuff involves a lot of brilliant engineering innovations and all that jazz but I just can't shake the feeling that it's just a temporary phase, an anomaly resulting from our profound ignorance of certain foundational issues regarding the nature of the universe.

I think we're missing something, something big, huge even, something that, if understood and properly exploited, would knock everybody's socks off and cause a lot of people to want to kick themselves in the butt for having been so blind for so long. What we're missing is a correct understanding of motion. Physicists may think they understand motion but they really don't. They made a wrong turn somewhere but it's not too late for NASA and the physics community to swallow their pride, shave their heads, don sackcloth, recite a few thousand mea culpas and do the right thing.

The Problem With Motion

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Olaf

3 Comments

• 877 Days Ago
• 09/21/2009

Slingshot redux

"The great ship started slowly, softly up the track, gathered speed, and shot toward the distant peak. She was already tiny by the time she curved up the face and burst into the sky. She hung there a split second, then a plume of light exploded from her tail. Her jets had fired."
From "The Man Who Sold the Moon," by Robert A. Heinlein, 1949.
What the book has to say about space ship engineering still rings true.

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