The Baikonour Cosmodrome
located in the middle of the deserted steppes of Kazakhstan
is the Russian space launch facility
used to start the journey towards the International Space Station
It is a huge complex that comprises several technical buildings:
some for assembling and preparing the rockets
and others to accommodate the technicians engineers and the crews
It was from Baikonur that Yuri Gagarin
began his extraordinary journey around the Earth
more than 50 years ago!
Today every launch of the Soyuz vehicle
brings three new crew members
onboard the International Space Station
They prepare for their mission in Star City
the training centre of the cosmonauts located near Moscow
Before stepping onto the launch pad
all the crew members have to undergo hundreds of training hours
both theoretical and practical to be able to operate and control the Soyuz spacecraft
in any situation
The practical part of the training
makes use of realistic models of the spacecraft that allow
the cosmonauts to feel almost as if they were in a real situation
They all follow the path of many others
who flew before them from Baikonour
Let's discover how a Soyuz rocket works
The rocket has a total length of approximately 50 m
and a diameter of up to 10 m
The total mass is about 310 tons
It consists of 3 parts called stages
A mixture of kerosene and liquid oxygen
is used in order to generate the required propulsion
On top of the rocket stands the Soyuz spacecraft itself
encapsulated within the structure of the rocket's nose
On the launch pad four green arms
ensure that the rocket is positioned properly
before lift-off
The arms will mechanically rotate away
to release the rocket while it leaves the ground
The training being successfully completed the crew members are ready for the launch
and the rocket stands on the launch pad
Two and a half hours before lift-off
the crew finally enter the spacecraft
and start preparing it for the launch in collaboration with the ground controllers
They are now set for the launch
The cosmonauts are now sitting on top of 300 tons of propellant
What happens if anything goes wrong?
The Soyuz rocket is equipped
with a robust and powerful system designed to save the crew
in case the rocket were to start burning or explode on the launch pad:
this is the launch escape tower
The launch escape tower is itself
a small yet powerful rocket
made up of several engines which use solid propellant
It is capable of quickly extracting the crew compartments from the rest of the rocket
in case of an imminent threat to the crew
like an explosion for instance.
The mechanism may be triggered automatically
or upon command from the ground controllers
On only one occasion in the history of Russian cosmonautics was this escape system put to use
In September 1983
while the rocket was ready to lift-off to bring two Soviet cosmonauts
to the Salyut 7 station a valve failed to close
just 90 seconds before final ignition
causing kerosene to spill onto the pad
and ignite
Fortunately, it was quickly realized
that the crew was endangered
and the ground controllers activated the escape system
Explosive bolts fired
to separate the crew compartments
from the rest of the spacecraft
and the escape motor fired
dragging the crew compartments free of the boosters
Although the two crew members
experienced an acceleration of 14 to 17 g for 5 seconds
they landed safely onboard their capsule some 4 kilometres
away from the launch pad
The g-load is a common way to express
the acceleration or in other words the force
that the crew may feel during changes in velocity.
The two cosmonauts Strekalov and Titov
would go on to fly several highly successful missions
in later years
This incident proved
how reliable the launch escape system really is
Let's go through the launch sequence now
At T-:00 We have lift-off
Full thrust is provided by the 4 side boosters
and the central block of the rocket
The core block is ignited at the same time as the 4 boosters
to provide an additional thrust
The rocket then initiates a manoeuvre called the pitch manoeuvre
to get the proper orientation towards the desired orbit
The acceleration on the crew members
starts to slowly increase to 1.5 g
45 seconds later
the rocket has already reached an altitude of 11 km
and a velocity of 1,640 km/h
This is the moment the rocket
must withstand the maximum pressure on its structure
The cosmonauts feel twice their normal weight on the ground
Looking at the projection of the track on the ground
we can observe that the rocket has already crossed 16 km.
After almost two minutes into the flight
the rocket is at an altitude of more than 40 km
high enough to get rid of the launch escape tower.
A few seconds later the four strap-on boosters
stop firing having consumed all the propellant they contained
Being of no use now they are jettisoned
from the main core
which continues to fire
and is now called the second stage
In case of a severe malfunction at this point
the spacecraft can still separate
from the rest of the rocket
and come back safely to the ground without the need for additional propulsion
The debris follow a trajectory that leads it to hit the ground
in an uninhabited area located more than 350 km from the launch pad
Soon the crew members will experience the maximum acceleration on their bodies
3.5 times their own weight
but only for a few seconds
This is the most physically
demanding moment for the cosmonauts
In the meantime
the second stage continues to fire for 3 more minutes
The structure that protects the spacecraft is then jettisoned
Once again the debris will follow a safe trajectory
to hit the ground 530 km away from the launch site
The spacecraft is now fully exposed to space
The light from outside
can now enter the crew compartment through the small windows
It's now been approximately 5 minutes since lift-off
Two seconds before the extinction of the second stage
the third stage is ignited
then the second stage separates from the rest of the rocket
The engine of the third stage
will continue firing for the next 4 minutes
As with the 4 boosters the second stage
follows a safe trajectory down to Earth
The rocket is already at an altitude of 170 km
and travelling at a velocity of 13,250 km/h
Then the circular section that links the second stage
with the third stage is jettisoned
while the rocket goes on to reach the targeted orbit
around 220 km above the surface of the Earth
Once on the desired orbit approximately 9 minutes into the launch
the last engine is cut-off
The spacecraft finally separates from the rocket
the cosmonauts can now feel the microgravity
Moments later the antennas
and the solar arrays are deployed
The spacecraft
is now on its way to the
International Space Station