хронология РН Союз

[Nicolas Pillet]

Кто-то знает в какие времии стартувует третий ступень РН "Союз" (11А511) ? В французком книге, я нащел "T+300 с"...

Спасибо!

[Bell]

Да, правильно.

[Андрей Суворов]

Для 11А511У

285,05 - Главная команда II ступени
287,29 - Разделение II и III ступени
305,78 - Сброс хвостового отсека III ступени

Это циклограмма пилотируемого "Союза-У"

[Nicolas Pillet]

(I go on in English because it is very hard for me to write in Russian with my computer... But you can answer in Russian!)

My problem is : on Videocosmos's website (http://www.videocosmos.com/soyuz18a.shtm), they say that the Soyouz 18-1 spacecraft was ejected at T+295 s.

But in the book "Soyuz, a Universal Spacecraft", they say that the craft was ejected four seconds after the ignition of 3rd stage (so, theorically, at T+304 s)...

Do you have informations about that?

[Андрей Суворов]

I think it was even later because flight abort happened after the vehicle lost it's orientation (7 degree from nominal). It happened after failure to jettison aft section of III-d stage shroud (3 panels separated and one did not). More likely it was 310th second of the flight

[Nicolas Pillet]

I've read that the safety limit was 10°...

What is this "III-d stage shroud"

[Андрей Суворов]

The IIId stage engine RD-0110 and all aft spherical section of the tank is protected with jettisonable cylindrical construction, it's weight is somewhat ~350 kg. It is separated from the IIId stage at T+305,78. It consists of 4 panels with their latches.

[Андрей Суворов]

Jettisonable section is painted orange - just below letters "СОЮЗ"

[Nicolas Pillet]

And at T+305,78, is the interface between II/III stage jettisonned too?

Or is the interface ejected earlier?...

[Андрей Суворов]

Well, to avoid weightlessness effects, IIId stage engine starts at the same time when IInd stage engine is cut off - at T+285,05. And more than two seconds IInd and 3d stages are pulled with IIId stage engine. Then at T+287,29 IIId stage is separated from the empty IInd, and, later, aft shroud is separated at T+305.

As for Soyuz-18-1 incident, different sources offer different versions.

Some even tell that 3 latches were released before nominal T+287,29 making a big eccentricity of pulled IInd stage. Other say separation of the second stage went nominally but aft shroud failed to separate. This gives us substantially different time of the launch abort event.

Look at this picture:

[Nicolas Pillet]

Well, to avoid weightlessness effects, IIId stage engine starts at the same time when IInd stage engine is cut off - at T+285,05. And more than two seconds IInd and 3d stages are pulled with IIId stage engine. Then at T+287,29 IIId stage is separated from the empty IInd, and, later, aft shroud is separated at T+305.

But at which moment does the interface section separate ? What I call the interface section is this : http://www.kosmonavtika.com/2.jpg

Some even tell that 3 latches were released before nominal T+287,29 making a big eccentricity of pulled IInd stage. Other say separation of the second stage went nominally but aft shroud failed to separate.

All my documents say that the failure was due to a problem with the interface section...
According to them, a mechanical shock did prevent the interface section from being separated, and thus the II stage AND the interface section were still attached to III stage during the separation of Soyouz...

Look at this picture:

Do you have a higher resolution version of this very interesting graphic?

[Андрей Суворов]

But at which moment does the interface section separate ? What I call the interface section is this : http://www.kosmonavtika.com/2.jpg

T+287,29

All my documents say that the failure was due to a problem with the interface section...
According to them, a mechanical shock did prevent the interface section from being separated, and thus the II stage AND the interface section were still attached to III stage during the separation of Soyouz...

It looks very likely but one point - the real excentricity in this case would cause 7 deg error in less than 0,5 second, not 4 seconds.

Look at this picture:

Do you have a higher resolution version of this very interesting graphic?

Yes and I can send it to you by e-mail