NASA’s Moon rocket could explode if the agency doesn’t cancel the dangerous launches, the expert says

NASA’s Moon rocket could explode if the agency doesn’t cancel the dangerous launches, the expert says

NASA’s Moon rocket could explode if the agency doesn’t cancel the dangerous launches, the expert says

NASA's Artemis I mission - the Space Launch System rocket and the Orion spacecraft - on the Kennedy Space Center launch pad under a full moon.  (NASA)

NASA’s Artemis I mission – the Space Launch System rocket and the Orion spacecraft – on the Kennedy Space Center launch pad under a full moon. (NASA)

On Monday, Aug.29, NASA powered its new large Moon rocket onto the Kennedy Space Center launch pad with plans to launch it on its first ever test flight, only to cancel the launch after encountering a number of problems that they conditioned one of the engines for launch.

So instead of a rocket launch, spectators who had traveled to Florida to try and catch the launch had to hurry to see if they could keep their hotel reservations until Saturday, when NASA hopes to try to launch. new. This is uncomfortable for some, but it’s not a bad thing, according to MIT aeronautics and astronautics professor Paulo Lozano, who also heads MIT’s space propulsion laboratory.

“I’ve been to Florida watching rocket launches and they rub and you all say, ‘oh, that’s so sad,'” he said. The independent in an interview. “But you don’t want to risk it because it’s a one-shot; they don’t have another Artemis on a block next door.

And this is ultimately the stakes NASA is playing with when launching a large rocket. It’s not that the problems encountered on Monday would have led to the rocket exploding, although at the extreme they might, said Dr. Lozano, but “there may actually be some engine degradation and you don’t want to risk it.”

Not when you can wait and try again another day – an intact rocket left on the pad can still do its job.

“Honestly, I wouldn’t be surprised if they scrub again for whatever reason,” he said. “It’s a very complex rocket and I’m sure they want to get it right.”

The problem NASA encountered on Monday had to do with the thermal conditioning of one of the four RS-25 engines in the center stage of the Space Launch System (SLS) rocket, a process called “engine bleeding” designed to cool the engines earlier. to accept a full stream of propellant liquid hydrogen.

“It’s actually a bit intuitive,” said Dr. Lozano. “What if you have something that is very cold and you put it in heat, or it is very hot, and you put it in the cold, like a glass of water? It can break, right? Because of the very strong temperature changes “.

Operating a finely engineered rocket engine at the wrong temperature could lead to the expansion or contraction of some components, he noted, some of which could then rub against others, a situation NASA engineers absolutely want to avoid. “This can lead to problems.”

Instead of using some sort of refrigeration machine to cool the engines, NASA drips some of the already very cold liquid hydrogen into the engine. But on Monday, a faulty valve in the SLS rocket’s liquid hydrogen tank appeared to exacerbate the difficulties in getting engine number three to cool enough, and with bad weather forecast towards the start and end of the two-hour launch window that morning. , NASA called the launch.

“There are so many different things that can go wrong in a complex system like this,” said Dr. Lozano. “If that was the only thing out of the bag, then I actually think it’s really great news. Of all the things that can go wrong, this one is easy to fix. “

For one thing, the RS-25 engine is a well-tested, reliable, and rated rocket engine for humans. It was the main engine of the Space Shuttle, Dr. Lozano points out, but NASA didn’t select it for the SLS program simply because it had a bunch of it in a closet.

“It is one of the highest performing engines ever,” he said. “If you look at the performance, which is characterized by the specific impulse – which is fuel efficiency, let’s say – this engine is very close to what is theoretically possible.”

Also noteworthy is that none of the Space Shuttle disasters, the explosion of the Challenger shortly after takeoff in 1986 or the melting of Columbia on reentry in 2003, were caused by problems with the RS-25 engine. Although these disasters highlight the importance of making sure every little detail is in place before launching a rocket, Dr. Lozano noted, they were caused by the broken O-rings in the Challenger’s solid rocket thrusters and damage to the Columbia’s heat shield during takeoff, respectively.

“They had nothing to do with these engines,” he said. “These engines are very, very good.”

In fact, the motors themselves are set to shut down automatically if something goes wrong during startup, Dr. Lozano said, even though the human launch team didn’t pinpoint the problem in advance.

“It takes five seconds to start these engines,” he said. “During those five seconds, the computers check every millisecond what’s going on. And if there’s anything funny about any engine, they’ll all shut down. “

So even though the countdown proceeds normally on Saturday, Artemis I does not start until the countdown actually reaches zero.

And it’s not a bad thing if it doesn’t. Dr. Lozano said he was puzzled to read a newspaper account of Monday’s canceled launch that described the cancellation as a failure.

“I said no, it’s not a failure; a failure is when the rocket explodes! In this case, it’s part of the process, it’s a normal process, ”she said. “If you think about it, if the rocket is actually launched, it’s a great, great, great success, just because of all the things that have to come together. “

Leave a Reply

Your email address will not be published.