Time line (by me). Probably incorrect.
- 4:00 reentry starts
- 5:00 some burning debris visible
- 6:30 end of plasma
- 10:30 strange flip , may be reoriented before second dive to atmosphere.
- 14:00 second plasma
- 17:42 active atmosphere guidance phase starts
- 19:45 - drogues deployed . first two thumbs a probably a lids
- 21:00 drogue cut, main deployed
- 21:31 mains fully opened
- 22:58 - attitude control kick in again while under shuts. Why ??
- 23:59 - landed ( watered?)
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https://www.youtube.com/watch?v=U88DzZcsubs
Here’s a link to the video. It’s actually exhilerating.
Looks like they did a skip at 4:00 with a bit of aerobraking before the actual reentry. That would make sense, since the velocity is incredible (11 kmps), coming straight from the moon. Velocities are lesser in case or reentry from LEO. Two-phase entry might reduce the load on the reentry shield and its occupants.
22:58 - attitude control kick in again while under shuts. Why ??
Just speculating. There isn’t much of an attitude change except in the initial few seconds, considering the amount of firing it does. It’s probably intended to consume the propellants and render the capsule safe. If that’s indeed what happened, they were likely firing opposing thrusters (in combo or alternatively), cancelling it out. There is such an operation in space tech - called passivation. It’s the space equivalent of a fuel dump.
PS: If anybody is wondering - this isn’t a pure ballistic reentry. Modern spacecrafts, even the capsule shaped ones, can change their trajectory by rolling on their axis of symmetry (the axis that passes through the center of the heat shield and top of the spacecraft). This may sound counterintuitive, but it has been used so many times already - like in case of the Mars rovers. They offset the C.G of the spacecraft a little bit away from the axis and uses it asymmetry to achieve guidance.
That’s really cool to watch.
I did not know they did so much active correcting during re-entry. Fascinating listening to those valves switching so fast!
Where is the link?
