It may be in trouble. Initial tracking data tweeted by Jonathan McDowell indicates that their orbit is off in inclination by about 0.4 degrees, which is about 50 m/s (probably a hundred kg of propellant). Their total budget for the ascent is about 100 m/s, and it seems unlikely that they have that much margin. So it’s possible that they don’t have enough to both get to ISS and then do a later deorbit, which means they’d have to abort without going to the station.
But the most likely explanation is that it’s just bad tracking data (maybe measuring during a burn?). We’ll find out at the next trajectory update.
[Friday-morning update]
Well, they docked, so presumably, they also have enough to get home.
The orbital inclination issue might be bad data, but the failure to deploy one of the two solar arrays isn’t. Is there any possible way the two issues might be related?
Perhaps Roscosmos needs a trampoline?
Apparently the Russian data looks better. More info as it becomes available.
Successful docking at ISS.
Looks like they managed to get docked. Inclination wasn’t a problem, but one of the two solar arrays on Soyuz didn’t deploy.
The issue wasn’t whether they had enough propellant to dock per se, but whether they’d then have enough to deorbit. But apparently the initial tracking data was off.
Makes a person think that being able to refuel in orbit might be good. OTOH, how much do you need to hit the earth? It’s a big target.
Well, from the ISS altitude you don’t technically need any fuel to return to Earth, just lots of time until the traces of atmosphere slow you down. However, if you want to bring people down alive and have some idea of where they will land, then you need around 50 m/s of delta vee.
No rounded corners, but its resilient as f*ck.