Submit a link Features Reviews Podcasts Video Forums More ▾

Supersonic airflow in a rocket nozzle

The blog Fuck Yeah Fluid Dynamics posted some stills from this video recently. The images were fantastic, but I didn't totally understand what I was seeing. Thankfully, FYFD blogger (and aerospace engineering Ph.D. student) Nicole Sharp was kind enough to answer my questions.

What you're looking at is a rocket engine. The video shows what happens to airflow in the engine as it goes from subsonic to supersonic. In the video and the pictures, you can see a dark red line moving down the tunnel. That's the edge of the shockwave that marks the boundary between subsonic air and Mach 1. You should also pay attention to the little black vortices that whirl away from the edge of the engine wall. Those are pretty important.

Read the rest

An airship boom in Southern California

Photo: the Aeroscraft in a hangar in CA. Image: Worldwide Aeros, Inc.

In the Los Angeles Times, an article about an aerospace industry boom of sorts in Southern California, involving new twists on an old technology: airships. Who's buying? The military, and other government agencies, primarily for defense and surveillance purposes.

[I]n recent years, the affordability of airships as well as developments in high-definition cameras, high-powered sensors and other unmanned technologies have turned these oddball aircraft from curiosities of a bygone era to must-have items for today's military. And airships increasingly are being used for civilian purposes.

The federal government is buying blimps, zeppelins and spy balloons, and many of these new-generation hybrid "lighter than air" aircraft are taking shape across California.

"So much is going on with airships in California now," Pasternak said. "It wasn't this way 10 years ago."

Of note, the difference between airships, blimps, and zeppelins:

Read the rest

US goes after bloggers for writing about imaginary laser weapon that could set insurgents’ clothes on fire

A number of journalists I know believe the Obama administration is the most secretive administration yet.

When I read news like this, I am inclined to believe them: the Naval Criminal Investigative Service is going after our pals at Danger Room, over a 5-year-old leak about a weapon that was never built.

"Federal agents are also chasing a leaker who gave Danger Room a document asking for a futuristic laser weapon that could set insurgents’ clothes on fire from nine miles away."

Total bullshit.

"We are on the fucking moon" (video)

[Video Link] Yesterday was the anniversary of Apollo 11's landing on the moon in 1969, the first time humans ever set foot on another world. Today, we discover this long-lost footage and audio from that historic moment. (thanks, inkfumes!)

"The Eagle has landed." Remembering Apollo 11: July 20, 1969

Left to right: Neil Armstrong, Michael Collins, and Buzz Aldrin, the crew of Apollo 11. Photo: NASA.


On this day in 1969, humans walked on the moon for the first time. The Apollo 11 spaceflight brought Americans Neil Armstrong and Buzz Aldrin to the lunar surface on July 20, 1969, at 20:18 UTC.

Michael Collins, the mission's third member, remained in lunar orbit. All three men returned safely to Earth after an 8-day mission that began with a Saturn V rocket launch from Kennedy Space Center in Merritt Island, Florida on July 16.

This was the fifth manned mission of NASA's Apollo program, which ran from 1963 to 1972 and included 6 missions that landed on the moon. These were the first and last times human beings set foot on another world.

Read the rest

Why the "Norway spiral" has the Russian government spooked

James Oberg at IEEE Spectrum has been following the "disaster-ridden" Russian missile program that lead to last month's spectacular spiral lights display over Norway. He offers some insight into the fascinating political story going on behind the scenes.

Designed to be the next-generation submarine-launched intercontinental ballistic missile (ICBM), Bulava has had 11 test flights since 2005--and has failed most of them, including the last three in a row. ... Beyond the threat to Russia's nuclear deterrent, the problems with the missile have become a major scandal for the Putin/Medvedev government. Hard-line Communist Party critics accuse them of letting the entire Russian military industrial complex decay to the point of danger.

IEEE Spectrum: Russia's Ailing ICBM Program

UPDATE: A commenter asked for information explaining how an ICBM could produce the phenomena seen in the video. The Christian Science Monitor interviewed a rocket scientist about this back in December. Their explanation includes a helpful video. New Scientist also had a similar, but not quite as thorough, interview with a different scientist, an astrophysicist.