They don’t really like it.

Three times is not a charm for NASA. For the third time in a row, the so-called wet dress rehearsal – the final dress rehearsal for Space Launch System (SLS) and Orion, prior to the very first test flight – called off early. The agency is now working diligently on solutions, so that the delay is limited.

What was that again?

In a few years, the time has come: NASA wants to bring the first woman and the next man to the moon. This will be done using their brand new launch vehicle, the SLS, and the brand new Orion space capsule. In mid-March, NASA announced that both were virtually finished and could undergo the last major test before the first-ever test flight: the so-called wet dress rehearsal†

More about the wet dress rehearsal
As mentioned, the wet dress rehearsal is the last major test for SLS and Orion before the very first test flight to the moon. During such a wet dress rehearsal, the fuel tanks of the launcher are refueled, after which all actions that must take place prior to a real launch – up to the countdown – are completed. There is not yet a launch during such a wet dress rehearsal. The purpose of the wet dress rehearsal is to practice filling the tanks and to have performed all necessary operations once before the real thing. If such a dress rehearsal goes smoothly, a more precise target date for the real launch can then be set.

The first attempt for the wet dress rehearsal took place at the beginning of this month. Unfortunately, the dress rehearsal was ended early at the end of the afternoon. First, there was a problem with the liquid oxygen temperature limit, which delayed the countdown by several hours. In the end, the entire test was called off because of a ‘broken valve’. The vent valve of the launcher turned out to be broken; a rather crucial part, as this valve regulates the pressure during refueling. And so it was decided to wet dress rehearsal to be postponed until a later moment.

Attempt two

The new attempt should have taken place on April 11. But this time too, the dress rehearsal was canceled when a problem was discovered in the motor of the upper stage. The motor on the top stage uses helium to bleed the engine and also to activate the valves on the top stage. However, the teams encountered a problem in maintaining proper helium pressure. And so it was decided to postpone this second attempt as well.

Custom Dress

NASA said it would try again a few days later. In the meantime, the culprit of the problem had emerged: the helium check valve was not functioning properly. And so it was decided to wet dress rehearsal forced to adapt. The giant launch vehicle would only be partially filled with fuel; the top stage would not be fully fueled. The rocket would then be driven back to the Vehicle Assembly Building – the site where the SLS was assembled – to address the problems that had arisen.

Three times is not a charm

However, things are not going well for NASA. Because unfortunately that third attempt has also fallen into the water. This was due to an unexpected leak, which released liquid hydrogen. This can be dangerous, because hydrogen is highly flammable. Fortunately, the leak was noticed in time. However, this also meant that this third frantic attempt was aborted prematurely.

Delay

How it goes now is expected to be announced tonight. A fourth attempt will probably be made. That the wet dress rehearsal however, now that it has been canceled three times in a row, is of course quite a damper for the US agency. This means that the test flight to the moon will also be delayed. The intention was that the Space Launch System and the Orion mounted on it would make the real test flight sometime in May. But due to the current state of affairs, that idea has been dropped.

However, there is certainly no adjustment from postponement. Because sometime in the next decade, NASA will deliver astronauts to the moon. The intended target of 2024 had already been declared unachievable earlier. At the earliest, NASA expects to be able to go to the moon in 2025. But before that, there are still important tests on the program. After the test flight to the moon – known as Artemis 1 – there will be both an unmanned and a manned test flight to our natural satellite. Only then is the long-awaited moon landing on the program. And it won’t stop at just one. Because NASA plans to return to the moon at least ten times.