What about explosive bolts?
On Sat, Jan 22, 2022 at 1:59 PM Henry Spencer <hspencer@xxxxxxxxxxxxx>
wrote:
On Sat, 22 Jan 2022, James Fackert wrote:
I don't think SpaceX uses any pyro actuation devices.All electrical andor
pressurized gas.
Indeed, the current manual cites it as a safety feature that "stage
separation and standard payload fairing separation" are non-pyro.
However, there are two different payload fairings; Falcon User's Guide,
Sept. 2021 edition, p. 9:
"The two halves of the extended fairing are fastened by a bolted frangible
seam joint. To deploy the fairing, redundant detonators initiate a
detonation cord contained inside an expanding tube assembly. The
detonation causes the expanding tube to expand outwards and break the
structural seam between the two fairings in a controlled and contained
manner."
Which is to say, an orthodox pyro-separated fairing design. (Perhaps the
extended fairing is something they buy rather than build themselves?)
Also, things like clamp-band systems for payload separation are deemed
part of the payload, not the rocket. SpaceX is willing to provide and
integrate certain standard sizes of clamp-band system as part of the
standard package. There are non-pyro clamp bands now, but I don't think
they are yet common for large payloads (smallsats do typically use
non-pyro separation).
They seem to have an aversion to inherently untestable one shot
actuators, and a sharp focus on reusability.
They've acquired this attitude somewhere along the way; Falcon 1 stage
separation was explosive bolts. (Experience with Falcon 1 ops may be
where they acquired their aversion to pyros. :-) )
Henry
