So after some further research (mainly TMA SUS training manual), turns out that as early as Soyuz-TM there is in fact active control during re-entry. It checks against a pre-programmed (one of several) "lost velocity / time" curve every 200 m/s, and adjusts the angle depending on if it's reached that speed too soon or late. In fact, it overcorrects to compensate the period when it was too shallow/steep.
Big question is, how much of this capability would 7k have already. Far as I can tell, there's no instrumentation output to the crew on the trajectory, nor the control inputs that later Soyuz has, so I would say the options are either "regular SUS" or ballistic, no manual mode. As for the normal re-entry, I think I identified the manual input to pick which way it would roll at the start of re-entry (left/right), which of course affects the lateral trajectory. Other than that, don't really see any of the versatility in speed/time curves modern Soyuzes have, especially since it relies on digital computers introduced after 7k. I could see though 7k having one single "hardwired" re-entry profile, generating analog signals proportional to the difference from the expected curve to feed into the roll channel. @Urwumpe did you ever find any specific info on early SUS?
There is of course the fact I wouldn't have said curve to implement anyway, but I think I could at least approximate one from TMA and hope it's good enough.
Big question is, how much of this capability would 7k have already. Far as I can tell, there's no instrumentation output to the crew on the trajectory, nor the control inputs that later Soyuz has, so I would say the options are either "regular SUS" or ballistic, no manual mode. As for the normal re-entry, I think I identified the manual input to pick which way it would roll at the start of re-entry (left/right), which of course affects the lateral trajectory. Other than that, don't really see any of the versatility in speed/time curves modern Soyuzes have, especially since it relies on digital computers introduced after 7k. I could see though 7k having one single "hardwired" re-entry profile, generating analog signals proportional to the difference from the expected curve to feed into the roll channel. @Urwumpe did you ever find any specific info on early SUS?
There is of course the fact I wouldn't have said curve to implement anyway, but I think I could at least approximate one from TMA and hope it's good enough.