[FPSPACE] Soyuz slow roll and balistic reentry

[Geert Sassen]

Hi,

no, sorry, my reference to 'horizontal' might have been a bit confusing, the
capsule is landing suspended from two parachute-lines with its soft landing
engines pointing streight down, the cosmonauts are then lying in a more or less
horizontal position. This is standard for all landings and not depending on
whether or not a ballistic reentry has been made.
Earlier in the landing phase the capsule is only suspended from one main
parachute line and hanging under an angle.

What I was trying to get a clear picture on is how critical those attitude jets
on the DM actually are. Note Soyuz only has roll-jets (no pitch or yaw), the
headlight shape together with the position of the centre of gravity take care
for aerodynamic stability and it will turn 'blunt end forward' independent of
any action from its attitude control jets (this unlike f.i. Apollo). Due to the
offset centre of gravity it can use a lifting-reentry and the lift force can be
varied by rolling the capsule, it will need the attitude roll-jets for this.

However, if there is some problem a ballistic reentry can be selected by placing
the DM in a slow roll (canceling out the lifting foreces). Basically, once the
capsule is rolling you won't need any attitude control system anymore, although
the landing will be somewhat rough which a lot higher G-forces. But you need to
put the capsule in a roll first to make this work, and possibly you need to
stop the roll before opening the main parachute. So how is this done, are the
jets of the DM still required to place the capsule in a roll on a ballistic
reentry or is there some other method which takes care of this? Would Soyuz be
able to make a safe landing if the attitude control jets are completely
inoperable from the very start?

Regards,

Geert.



David Anderman wrote:

> Geert,

> Are you stating that for ballistic re-entries, the capsule is to land 
> in this horizontal attitude?

> DWA

At 05:30 AM 3/31/2007, Geert Sassen wrote:
> >During the last phase of
> >the landing the parachute changes from single point suspension 
> >(capsule hanging
> >under a slight angle from one main parachute line) to double point
suspension
> >(capsule hanging horizontal from two main parachute lines).

-----
Geert Sassen
geert at navtools.nl