If the Soyuz is leaking coolant, are these going to be little high-velocity ice balls?
Tangentially related question: How dangerous are high-velocity gas clouds? Like, say rocket exhaust? Is that a thing, or does it always disperse quickly enough to to be a non-issue?
> If the Soyuz is leaking coolant, are these going to be little high-velocity ice balls?
They'll boil or sublimate in sunlight, and while they'd notionally condense in the earth's shadow their molecules will be too spread out for that to matter. So any ice balls will last for at most half an orbit, which I think is less than an hour at that altitude.
Velocity is relative; they'd be high-velocity relative to anything going straight up through that orbit, or in a retrograde orbit, but they're low-velocity compared to the ISS or anything coming up to meet it.
> Tangentially related question: How dangerous are high-velocity gas clouds? Like, say rocket exhaust? Is that a thing, or does it always disperse quickly enough to to be a non-issue?
They'll dissipate very quickly, space is at zero pressure.
"The leak appears to have originated in an external cooling loop located at the aft end of the Soyuz MS-22 spacecraft. Public affairs officer Rob Navias, who was commentating on the spacewalk for NASA Television, characterized the spacecraft as leaking "fairly substantially." Video of the leak showed particles streaming continuously from the Soyuz, a rather remarkable sight. This was likely ammonia, which is used as a spacecraft coolant, although Russian officials have not confirmed this."
The coolant is (appears to be) low velocity wrt to the ISS. Everything appears to be stable for now (and isn't causing a major impulse or torque to the ISS).
My guess (with no expertise to back it) is that it should dissipate quickly and will not be an issue to anyone.
Tangentially related question: How dangerous are high-velocity gas clouds? Like, say rocket exhaust? Is that a thing, or does it always disperse quickly enough to to be a non-issue?