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First details of starship's first orbital test flight!
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Wow 20 odd clamps and they all need to release exactly at the same time within a fraction of a second.
The picture from this tweet makes it appear that they are more like supports (and they are called such in the annotations), rather than actual clamps:
That having been said, your point is an interesting one, all 20 would need to retract simultaneously otherwise it appears they might hit engine nozzles.
I guess if you can coordinate firing and throttling 29 rocket engines to sub-second accuracy, sync'ing 20 hydraulic rams isn't that big of a deal...
In general "clamps" provide a rocket some or all of:
--Supporting the gravitational load of the launcher when verticalized. This seems to be the case with Starship.
--Resisting tipping (lateral load) while verticalized, primarily due to wind. This is likely the case with Starship. Its a big rocket, as it were.
--Providing resistance against launch thrust for early motor operations. While not represented as such, IMO this is likely the case with starship. Basically, the motors need to come up to some nominal flow state/thrust before the vehicle is released, and its hard to imagine all of the motors at that point won't produce enough thrust to offset the gravitational load.
As far as sequencing, the good news is that it doesn't need to be THAT precise, at least in so far as being a more difficult technical lift than any other sequencing that's going on. The ~zero velocity and acceleration in the 'long instant' means any fractional timing offset is pretty much hit with a numerator of "0" and easily overcome-able by normal flight controls. Obviously a properly hung up clamp would be a Bad Deal, but that's both unlikely and another story...
Related, its also plausible they early-release some of the clamps such that the result is a KISS number of clamps actually required to hold back the rocket.
Its also likely that the thrust of the launcher can actually move/lift the clamps in an anomaly scenario. If there are solids involved this is basically a certainty; with liquid motors one could at least imagine a scenario where an anomaly might result in shutting down the motors instead...though methinks you'd still want that feature.
Guessing it is a single (or two) Ram that opens everything at the same time.
I thought the transporter/erector did that job of holding the F9 on top and releasing and angling back at the last minute. Holding on the top is a lot more easier than the clamps holding in the bottom.
FWIW I'd guess the KISS approach would be to have each clamp (or perhaps small group of clamps) be mechanically isolated and independently commanded. Daisy chaining mechanical linkages around the circumference seems complicated, and some distributed hydraulic network seems less than ideal in the soon-to-be-deep-fried environment.
But I also don't know for sure.
It certainly provides provide some resistance (hence my 'in general' caveat), but obviously there are nominal situations where the transporter is detached (just before launch) and certainly anomalous situations that would need to be accounted for (like aborting the launch, finding the transporter has failed open, and winds picking up).
Side loading of the launcher (= overturning or 'tipping') can be visualized as a ~vertical 'motion' at the base of the launcher. So...to resist that side load beyond what the mass of the launcher will provide, one would place a a vertical clamping load at the base of the launcher. That of course already exists with the restraint clamps which are designed to resist the full thrust + any overthrust and + any safety margin, and that rack up hand-waves to well over 2 million pounds.
There is so much paraphernalia attached to the outer skin of the booster that is exposed to the elements. Will they all survive the rigors of rocket flying through the atmosphere at MaxQ?
I don’t recall any such big items attached to the outside of any other rocket?
favo
P3D+ owner
I'm pretty sure at least some of that (e.g., the COPVs) will be covered before they fly the booster.
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