Date, reason for the postponement… all about the second attempt of Artemis I

The first launch of the gigantic Space Launch System, which was to set off for the Moon on August 29 with its Orion capsule, unfortunately had to be aborted due to a technical problem. The departure is now scheduled for Saturday, September 3.

Why has the launch been postponed?

During the battery of routine tests that precede each launch, the ground teams noted the presence of a hydrogen leak in the cooling circuit, or more precisely in the junction between the respective pipes of the launcher and the launch pad. This has since been fixed and this item should no longer be a problem.

The other concern is that the technical teams had failed to cool one of the four RS-25 engines. Several observers then spoke of a possible failure of a cooling valve. According to the latest news, it seems that this possibility has been ruled out; NASA has since announced that it suspects a malfunction of a temperature sensor, and not of the valve itself. The situation would therefore be less problematic than expected.

A godsend, as it means the engine had probably been cooled properly; the rest of the operations must therefore have been much simpler than if the hydraulic system had given way entirely. In theory, it would suffice to replace the sensor in question and ensure that it is working. A much faster operation than rechecking the entire system for leaks.

©Boeing

Why didn’t NASA take advantage of today’s launch window?

There was indeed a window of opportunity that could have allowed the SLS to take off today, at least on paper. But orbital mechanics are not the only element to be taken into account when deciding on the departure date.

The SLS and Orion will also have to sustain themselves, and they will do so thanks to the solar panels mounted on either side of the capsule. However, if the rocket had left today, it would have spent a long time in the shadow of the Earth; we then speak of an eclipse zone, and this means that it could have been completely deprived of energy in the event of a major unforeseen event. A situation that would obviously put the entire mission in danger.

NASA therefore had to exclude all launch windows that had this characteristic, starting with today’s. The next two openings compatible with this imperative will arrive on Saturday 3 and Monday 5 September.

We will still have to wait for the result of the new preliminary tests, but also the conclusions of the meteorologists, because the conditions on site must imperatively be ideal; no question of taking the slightest risk with this machine already much criticized for its status as a huge money pit. Currently, NASA estimates the chance of favorable weather to be around 60%.

Where and when to watch the launch?

NASA is now targeting a launch tomorrow, September 3, at 8:17 p.m. It will be possible to attend on the Nasa T channel, on the agency’s mobile application, or directly on its website.

The firing window will last two hours. If the SLS has still not taken off after 10:17 p.m., for technical or weather reasons, you will have to be patient over the weekend and wait for Monday’s launch window.

We therefore give you an appointment on these two dates to see whether, yes or no, the Artemis program will finally get down to business after years of uncertainty and controversy related to delays, the explosion of costs and limits. of this non-reusable launcher.

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