NASA finds old demons with liquid hydrogen

“11 space shuttles had to leave the launch pad […] and two of them did it twice in a row” recalled this Saturday the French astronaut Thomas Pesquet, as if to justify the cancellation of the flight of the Artemis 1 mission, made public a few minutes earlier.

As the Norman says so well, the space shuttle also encountered reliability problems, and for the same reasons that block the SLS today and Artemis 1 on the ground. Like them, the SLS suffered a leak in its liquid hydrogen tank.

A problem known to NASA for decades

It must be said that managing this gas in a liquid state requires a very precise temperature (-256°C) and a special pressure level of the gas to liquefy it. So much data which is very complex to manage and which, at the slightest detail, can put the whole mission in danger.

During the Challenger accident in 1985, it was not even the main tank (filled with liquid hydrogen) that leaked, but an external booster that works with powder. The result, however, was dramatic. So when on Saturday on the launch pad, the NASA teams realized that the liquid hydrogen tank was the victim of a leak, mass was said.

Although they tried three times to end this leak, they were unsuccessful, and after hours of radio semi-silence, Launch Director Charlie Blackwell-Thompson decided to put it on hold. .

Next flight in October

In a press conference that followed shortly after, NASA has announced that it will not attempt to fly its rocket again anytime soon. The American space agency wants to learn from its mistake and allow time to correct this leak problem. As a reminder, Artemis 1 should have taken off on August 29, but this attempt was aborted due to an engine fuel pressure problem.

During the second test of the rocket, this Saturday, September 3, it was therefore the tank that did not hold, forcing the NASA teams to give up once again. According to the first information given by NASA, the next launch window for Artemis 1 should be in October. This delay of a few weeks should not however have too many consequences on the rest of the calendar, the rest of the missions not being planned until May 2024.

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