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I read somewhere (and can’t seem to find the link) that the rollback to the VAB is because there is a small battery powering the abort system that has an approx

I read somewhere (and can’t seem to find the link) that the rollback to the VAB is because there is a small battery powering the abort system that has an approximate 3 week lifespan. And this past sat was near the end of that timeframe.

snewman 4y ago
The lifetime of the launch abort battery is indeed a factor. It is normally rated for 20 days, and they extended the rating to 25 days for this launch, but when that time is up the entire vehicle stack does need to be rolled back to the VAB to access and (replace? recharge? retest?) the battery. However, my understanding is that the current rollback is needed to address the hydrogen leak; they are not (quite) yet at the end of the rated battery lifetime.
icegreentea2 4y ago
There are two reasons to rollback to VAB. The first is as you say, there's a timeline constraint based on the launch abort battery. It's previously been stated that NASA could attempt to get a waiver for the timeline. But second reason is that the number of remedial and inspection actions you can perform on the launch pad is obviously more limited than in the VAB. Given that NASA did try for an immediate relaunch, it's likely that they've already tried and exhausted their highest value launchpad inspection and remedial actions.
perihelions 4y ago
- "Due to the orbital dynamics of the Artemis I mission to fly an uncrewed Orion spacecraft to the Moon, NASA will next have an opportunity to launch from September 19 to October 4. However, making that window would necessitate fixing the rocket at the pad, and then getting a waiver from the US Space Force, which operates the launch range along the Florida coast." - "At issue is the flight termination system, which is powered independently of the rocket, with batteries rated for 25 days. NASA would need to extend that battery rating to about 40 days. The space agency is expected to have those discussions with range officials soon." - "If the rocket is rolled back to the Vehicle Assembly Building, which would be necessary to service the flight termination system or perform more than cursory work at the launch pad, NASA has another Artemis I launch opportunity from October 17 to October 31." https://arstechnica.com/science/2022/09/years-after-shuttle-nasa-rediscovers-the-perils-of-liquid-hydrogen/ https://arstechnica.com/science/2022/09/years-after-shuttle-...

snewman 4y ago

The lifetime of the launch abort battery is indeed a factor. It is normally rated for 20 days, and they extended the rating to 25 days for this launch, but when that time is up the entire vehicle stack does need to be rolled back to the VAB to access and (replace? recharge? retest?) the battery. However, my understanding is that the current rollback is needed to address the hydrogen leak; they are not (quite) yet at the end of the rated battery lifetime.

icegreentea2 4y ago

There are two reasons to rollback to VAB. The first is as you say, there's a timeline constraint based on the launch abort battery. It's previously been stated that NASA could attempt to get a waiver for the timeline. But second reason is that the number of remedial and inspection actions you can perform on the launch pad is obviously more limited than in the VAB. Given that NASA did try for an immediate relaunch, it's likely that they've already tried and exhausted their highest value launchpad inspection and remedial actions.

perihelions 4y ago

- "Due to the orbital dynamics of the Artemis I mission to fly an uncrewed Orion spacecraft to the Moon, NASA will next have an opportunity to launch from September 19 to October 4. However, making that window would necessitate fixing the rocket at the pad, and then getting a waiver from the US Space Force, which operates the launch range along the Florida coast." - "At issue is the flight termination system, which is powered independently of the rocket, with batteries rated for 25 days. NASA would need to extend that battery rating to about 40 days. The space agency is expected to have those discussions with range officials soon." - "If the rocket is rolled back to the Vehicle Assembly Building, which would be necessary to service the flight termination system or perform more than cursory work at the launch pad, NASA has another Artemis I launch opportunity from October 17 to October 31." https://arstechnica.com/science/2022/09/years-after-shuttle-nasa-rediscovers-the-perils-of-liquid-hydrogen/ https://arstechnica.com/science/2022/09/years-after-shuttle-...