The
Indian Space Research Organisation (ISRO) will set a record when it launches 103
satellites in one go on a single rocket in the first week of February.
Explaining
how all the satellites will be placed in orbit, Dr. K. Sivan, Director of the
Vikram Sarabhai Space Centre (VSSC), Thiruvananthapuram, said: “The satellites
will be separated from the launch vehicle in different directions. The
separation angle and time of separation will be such that one satellite will
not collide with another.”
The
satellite separated from the launch vehicle will have a relative velocity of
one metre per second. So after 1,000 seconds the distance between a satellite
and the rocket will be 1,000 metres. “The satellite that gets launched first
will move at a relatively faster velocity than the next satellite that is
launched. Due to different relative velocities, the distance between the
satellites will increases continuously but the orbit will be the same,” he said.
“When
the vehicle reaches the orbital condition, we will wait for the disturbances to
die down before the preparation for separation begins,” Dr. Sivan explained. At
an orbital altitude of around 500 km, it would take the vehicle 90 minutes to
complete one orbit. “So we have sufficient time to launch all the 103
satellites,” he added.
Even
one degree difference in separation angle combined with relative velocity will
ensure that no two satellites would collide. “The satellites will be injected
into orbit at different locations at different angles, at different times and
different orientations,” Dr. Sivan said.
In
June last year, ISRO launched 20 satellites in one go. It took about 26 minutes
to launch all the 20 satellites. In 2008, ISRO launched 10 satellites in a
single mission. The highest number of satellites launched in a single mission
so far has been 37 by Russia in 2014; NASA launched 29 satellites in one go in 2013.
ISRO’s
workhorse PSLV (C37) with 103 satellites will be launched from the Satish
Dhawan Space Centre in Sriharikota in Andhra Pradesh. With the exception of
three satellites from India, the rest are from other countries.
Source :http://www.thehindu.com/
