Comment by JumpCrisscross
11 hours ago
> not clear what "full duration static fire" means
You fire the rocket as if it’s going to space, but you keep it on the pad. (From the engine’s perspective, it did a full launch.)
11 hours ago
> not clear what "full duration static fire" means
You fire the rocket as if it’s going to space, but you keep it on the pad. (From the engine’s perspective, it did a full launch.)
I think the point is that that phrasing has been used by rocket companies to mean a whole range of different amounts of fuel load, it's not very precise wording in practice.
From the industry: I would expect to hear "mission duty cycle" in that case. "Full duration" doesn't have a consistent meaning (a fact which is sometimes used to the marketing team's advantage).
Flight computer tells engine to go. Full go, launch sequence. Engine goes. To me, anything but that isn’t a full-duration anything.
If clamped down, it’s a full-duration static fire. If clamps release, it goes to space. Basically, if the engine can’t tell (apart from atmosphere, which is a big apart) it isn’t going to space, it’s a FDSF. It’s a whole-engine show. If you’re running parts through a full duty cycle, that can be done in a lab (or on a stand).
Sorry, no, I've worked on multiple launch vehicles and "full duration" doesn't mean anything consistent to anyone actually working on rockets.
The problem is that there is no standard meaning for the "full duration" in this context.
Some reports say that this means "running all seven BE-4 engines at full thrust for up to 38 seconds".
In flight the engines fire for 190 seconds.
So what the full duration means, and whether they fill the tanks with just enough fuel for the firing, or with a larger amount to help the clamps to hold the stage down, all this we will probably only find out from the investigation, if the results are ever published.
I think it's amazing they can basically hold a rocket down and let it launch like that without things exploding or shearing apart from the forces. Are those the same bolts as the exploding ones they would use for a normal launch?
(on that note it's also amazing that these exploding bolts are so reliable, I can imagine even a single one not releasing would cause... Issues)
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