Soyuz from ISS

[wendilla]

Why has the Soyuz tma-11 just taken a matter of hours to come back from the space station this morning compared with the shuttles that takes up to 2 days. Thanks

[kempie]

It physically only takes a matter of hours (weather permitting) for each type of craft to undock, deorbit, reenter and land however the Shuttle procedure includes a day or so for the crew to test their systems and check out any damage that invariably occured during the mission.

Soyuz-TMA just makes a dash for home. Perhaps this may account for the last 2 missions (10 and 11) encountering problems after deorbit which resulted in each mission transitioning to ballistic reentry.

[wendilla]

Thank you very much for your reply so this means that the soyuz does not orbit round the earth like the shuttle on it's way down or I am making any sense what I am trying to get at is does it come straight down without any orbiting first. I have watched most of the shuttle landings and take off on the nasa here on pc.I

[Teddio]

Hi wendilla
A spacecraft in low-Earth orbit is travelling at a speed of 17600 MPH and takes 90 minutes to complete one orbit of the Earth. To achieve re-entry with the minimum expenditure of fuel, the craft will fire its rocket engines against the direction of travel and slow down to a speed of approx 17000 MPH. This will result in it entering an elliptical orbit, losing height and striking the upper atmosphere on the opposite side of the Earth.
Due the atmospheric drag, the ISS loses a few kilometres of height every month and has to have periodic re-boosts from an attached rocket.

[wendilla]

Thank you Teddio yes I found all that out by watching HSF tracking but did not know it had to be re-boosted up every month.In England here I have seen a few good sightings when we have clear skies but just could not understand why the Soyuz came back faster than the shuttles.

[kempie]

The Soyuz is a small capsule which acts as a taxi service for the return flight - it's only function is to return to Earth.

http://www.russianspaceweb.com/soyuz.html

The Shuttle is more like a bus/goods vehicle/mobile laboratory. After undocking the crew may carry out external work or experiments, check for and carry out repairs and then ensure any payload in the cargo bay is properly stowed before the return flight commences.

[wendilla]

Thank you for your reply and interesting reading about the soyuz ect..I am not in the least technichal but I am very interested in what goes on and any information is appreciated.