Shulou(Shulou.com)11/24 Report--

Beijing, Aug. 30 (Xinhua) despite the great efforts made by NASA engineers and technicians, they did not allow the Space launch system (SLS) giant rocket to take off on Monday.

The ▲ NASA moon landing rocket failed to launch on Monday

During the countdown on Monday morning local time, the rocket initially encountered several problems, and eventually encountered a technical problem that the launch team could not solve: the RS-25 rocket engine could not cool properly before firing. Even if the engine problem is resolved, the weather off the coast of Florida on Monday morning was more dangerous than expected.

NASA promoted Monday's launch, including inviting celebrities to watch the rocket launch. Moreover, US Vice President Harris also came to the scene to deliver a congratulatory message after the successful launch of the rocket.

▲ US Vice President Harris was supposed to deliver a congratulatory message.

However, Harris, NASA engineers and VIP viewers may be disappointed. Harris did not give a speech after the NASA cancelled the launch, but told reporters: "Innovation requires moments when you experiment with something that has never been done before and then reorganize (after failure). You will figure out what the next step to achieve the ultimate goal will be. For us, the ultimate goal is to land on the moon and show how humans live and work on the moon."

Hasty launch caused problems Monday's attempt may have been in a bit of a hurry, why? Because NASA didn't take into account all the things that could go wrong when launching the rocket.

At first, NASA launch controllers successfully solved a series of problems. For example, fuel injection was delayed for nearly two hours due to lightning near the launch pad, forcing the team's schedule to be compressed. Efforts can only be made before the launch window opens at 08:33 EDT (20:33 Beijing time).

When the launch team began to charge the propellant, the filling of the large liquid hydrogen tank was hampered by a leakage of an 8-inch entrance to the liquid hydrogen tank. This problem is eventually solved by stopping the process and restarting the propellant charge. NASA basically solved this problem by shutting down SLS and restarting it.

There's a problem with the 40-minute countdown.

After that, the countdown went smoothly for about an hour until there was a problem with one of the rocket's four main engines. As part of the pre-launch program, the cryogenic propellant is "drained" from the fuel tank into the engine and cooled to about 5 degrees Celsius before flight. In technical terms, the actual temperature given by Mike Salafin (Mike Sarafin), the mission manager of Artemis 1, is 500F (about 5C).

As a result, in the process of troubleshooting the engine, launch controllers could not find a way to solve the problem of the core stage of the rocket, so the launch plan was cancelled.

"I am very proud of the launch team," NASA Director Bill Nelson (Bill Nelson) said at a briefing after the launch was cancelled.

Nelson should be proud of the launch team, considering the hard work they did late Sunday night and Monday morning in the final phase of the countdown. But flight controllers probably shouldn't have faced such an awkward moment.

Incomplete testing began in April this year, NASA conducted four "wet dress rehearsals" tests, with the goal of filling up the SLS rocket with fuel and simulating the completion of the test before the main engine was ignited with 10 seconds left in the countdown. However, all four tests ended ahead of schedule. In the fourth attempt in June, engineers simulated rocket tests with 29 seconds left in the countdown.

However, in order to enter the final stage of the countdown, NASA had to "deceive" the flight computer. During the test, a 4-inch hydrogen pipeline (hydrogen line) suffered a seal leak, which is smaller than the 8-inch pipeline that went wrong on Monday. However, in order to complete the wet dress rehearsal, NASA chose to cover up the leak of the ground launch program because the ground computer controlled most of the countdown program.

Space launch system

Because of this cover-up, NASA was unable to complete the test of the engine cooling part. If the test had been carried out, NASA would probably have found the problem that led to the cancellation of Monday's launch. So, in hindsight, NASA should have completed a full wet dress rehearsal before launching the rocket. As a result, when the world was expecting the launch of the SLS on Monday, NASA actually conducted its fifth wet test, which was complete this time.

Why not conduct a full test? So why did NASA launch the rocket without conducting a full test?

Jim Free, head of human exploration development at NASA, defended the decision. "We still feel that today's launch is the right thing to do." He said of Monday's launch attempt.

Fry said NASA had to consider the wear and tear involved in additional wet-loading tests of SLS rockets to and from the launch pad and pressurization of the fuel tank during refueling. During the countdown, NASA must balance these risks and challenges.

Not giving up now, NASA may withdraw the rocket to the aircraft assembly building at the Kennedy Space Center. NASA officials said they did not rule out a launch at 12:48 EDT on Friday, September 2. NASA mission controllers will meet on Tuesday afternoon to discuss possible solutions to engine exhaust problems, before announcing launch plans.

Salafin, Task Manager of Artemis 1 (middle)

Salafin, mission manager of Artemis 1, said Friday was "certainly possible", but pointed out that the launch team needed time to comb through the data before determining the possibility of a successful launch.

"it is not impossible to launch on Friday. We have to try all the possibilities. We are not ready to give up." Salafin said.

If the SLS rocket cannot be launched before September 5, it will need to return to the hangar for additional repairs. By then, the rocket will probably not be able to launch before mid-October.

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