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My former classmate isn’t the only one watching this video, either. It’s been shared more than 350,000 times already and garnered more than 71,000 likes. Plus, it’s not the only video that uses Jeremy Clarkson to claim that NASA is pumping out clouds. A quick Google search of “Top Gear NASA engine test” brings up a whole host of videos that claim NASA has cracked how to modify the weather. But NASA hasn’t.
The video is actually an edited clip of two different rocket engine tests at NASA’s Stennis Space Center in Mississippi. The first couple of seconds show the test-firing of an RS-25, an engine that was used on the Space Shuttle and will be used to power NASA’s next big rocket, the Space Launch System. The latter part of the clip is from a 2001 BBC television series called “Speed,” hosted by Clarkson. In the footage, Clarkson attends the test-firing of an RS-68, according to NASA (though a YouTube video from Top Gear incorrectly states he’s at a solid rocket booster test). It’s an engine used in the Delta IV family of rockets made by the United Launch Alliance. However, the engines can’t be seen in the video; they’re hidden by the test stands.
The clip that’s circulating on Facebook conveniently leaves out the part of the BBC video where Clarkson describes that he’s at an engine test. Instead, it just focuses on the part where he talks about the clouds that are produced in the process. (These clouds are just really, really hot steam.)
The rocket engines being tested in the video run on liquid oxygen and liquid hydrogen propellants. When these two materials combine and combust in an engine, they make large clouds of steam that exceed 6,000 degrees Fahrenheit. During a launch, bystanders can see these exhaust plumes trailing behind a rocket as it ascends into the sky. But when a rocket engine is tested on the ground at Stennis, the test stand makes the plumes shoot out horizontal to the ground.
The really neat thing about the steam produced by these kinds of engine tests is that it can create rain nearby, which Clarkson experiences in the video. The steam rises after the test and cools in the air. It then turns back into water and rains down on any surrounding bystanders. That isn’t the point of the test stand, though — something the bogus video elides. Instead, that rain is just a (delightful) side effect of the engine test. And since the clouds are just water, the plumes aren’t polluting the atmosphere.
So why is this video circulating now? Well, it was shared on April 1st, so perhaps it was all an elaborate April Fools’ joke that people are just now taking seriously. However, the video also contains a watermark in the top right-hand corner that reads “email@example.com.” That seems… suspicious.
So, if you see this pop up on your News Feed, just know that NASA does not have a machine dedicated to producing clouds. But technically a rocket engine test can sometimes make it rain.