When you prepare for a flight on the Soyuz, you first learn about all the on-board systems one by one: you spend a lot of time in the classroom learning the theory and occasionally you get some time in the simulator, specifically dedicated to the one system you're studying. Once you've passed the exams on all the systems, you graduate to the complex simulator sessions that I've written about multiple times and in which you integrate all your knowledge of the separate systems into the actual flight operations.
Today Anton and I exceptionally reverted back to a single-topic practical training session, learning about new procedures to be applied in case of a computer failure just after undocking.
See, our Soyuz will be docked to the MRM-1 module, just like one you see in this beautiful image by the Expedition 38 crew. Like the photo shows, in the standard ISS attitude the MRM-1 points nadir, towards Earth. Typically, when a vehicle undocks the Station it rotated 90° so that the docking port faces aft - that makes if easier from an orbital mechanics point of view, because the simple impulse given by the spring-loaded pushers in the aft direction is enough to guarantee that there will be no collision, even if the Soyuz was unable to perform the separation burns.
However, it would be really nice to be able to leave the Station in its nominal attitude: it takes fuel to rotate it and the mechanical loads can cause fatigue on the structure, which affects the Station's lifetime.
If the docking port is nadir, though, proper separation burns must be performed to ensure safety. That's why we now have new procedures in development that allow the crew to give the burns manually, should the computer fail before completing them.
Was fun to try something new!
Photo: ISS Expedition 38#SamLogbook #Futura
(Trad IT) Traduzione in italiano a cura di +AstronautiNEWS
(Trad ES) Tradducción en español aquí:http://www.intervidia.com/category/bitacora/
(Trad FR) Traduction en français par +Anne Cpamoa