A Rocket You Can Count On

When it comes to dependability, no human-rated rocket will be more critical than the descent engine for the next lunar lander, which will fire to slow the astronauts to a safe and gentle touchdown on the moon. NASA is currently testing various configurations of the descent engine, shown here in a chamber at Pratt & Whitney Rocketdyne’s location in West Palm Beach, Florida. Throttling at various levels between 15 percent and 100 percent of full power, the descent engine will give future astronauts precise control over their landings. As liquid oxygen at -297 degrees F combines with liquid hydrogen at -423 degrees F and combusts, gases containing hot steam are propelled out the nozzle. Because the nozzle is itself supercooled, this steam condenses to form icicles on the rim, right next to 5,000-degree-F exhaust. Video: NASA (1:55)

Latest Videos

Preview thumbnail for video'What do Native American carvings in French World War I quarries mean?
What do Native American carvings in French World War I quarries mean? (2:53)
Preview thumbnail for video'What did World War I soldiers leave behind in their secret bunkers?
What did World War I soldiers leave behind in their secret bunkers? (2:47)
Preview thumbnail for video'How the massive ALMA antennas move in perfect unison
How the massive ALMA antennas move in perfect unison (1:53)
Preview thumbnail for video'These antennas weigh 100 tons each
These antennas weigh 100 tons each (2:18)
Preview thumbnail for video'The plane crash that claimed three rock legends
The plane crash that claimed three rock legends (2:37)
Preview thumbnail for video'Preparing for nuclear Armageddon
Preparing for nuclear Armageddon (1:55)
Preview thumbnail for video'Cranberries in New England
Cranberries in New England (1:23)
Preview thumbnail for video'Scandal in the Biosphere
Scandal in the Biosphere (2:26)
Preview thumbnail for video'Reptiles can’t fly. But this one glides like a pro.
Reptiles can’t fly. But this one glides like a pro. (1:43)