Remember Monday, when JF Mezei asked plaintively:
> On 2021-11-08 22:05, Snidely wrote:
>> [This reduces the mass the Dracos have to apply delta-vee to, as well
>> as reducing the parachute load]
> Are what altitude is the trunk jettisoned? It is allowed totally
> uncontroled re-entry anywhere at any time because they are confident it
> fully burns up?
It's between the departure phase burn (aka landing phase burn) and the
deorbit burn. This flight also included an out-of-plane burn that was
a fuel dump, and this was also before trunk separation.
However, we don't get the "speedometer" data for height and velocity at
any point (except when we get a few views of the consoles).
> On other ships the excess weight is ditched after de-orbit burn to force
> it down in same orbit. But those happen to have de-orbit engines and
> tanks on the "trunk" portion, so keeping the trunk attached for de-orbit
> burn is sort of mandatory.
Most Apollo reentries were basically set up from the moon, so SM
separation happened well after the "de-orbit" burn. Skylab and ATSP
provide the return-from-orbit scenario, and it appears for ATSP that
the SM separated after the de-orbit burn (no scare quotes). Skylab was
probably the same, but I don't see confirmation of that in a quick
Remember, though, the SM had a pretty big engine ... that rocket motor
was capable of doing the lunar return burn.
Soyuz separated the orbital and descent modules after the de-orbit
[I'd expect a similar description of the Chinese capsules, based on the
"they copied the Soyuz" trope]
Gemini had the reentry rockets ("retrograde rockets") on the Adapter
Module, so that had to be jettisoned after the deorbit burn.
Astronautix says, "The sections of the adapter module remained in
decaying orbits and were burned up during reentry." That hints that
the AM might not have entered as quickly as the Reentry Module.
> Yet once detached both parts follow their own trajectory and the
> parachutes never worry about the trunk/service module because it only
> needs to support the small capsule.
Sure, so the NASA/SpaceX commentary is kinda being redundant about the
jettison making it easier on the parachutes, but still.
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the questions -- old and new, good and bad -- this newest tool lets us
ask. (R. Lerhman, CSMonitor.com)