SCIENCE | A Hundred- and- three Satellites At Once: ISRO's Next Launch Mission

In 2014, Russia's Dnepr rocket- a transformed inter-continental ballistic missile- successfully launched 37 satellites into orbit in one go- a feat that to this date holds the record of launching the most satellites at once. Hopefully, the Indian Space Research Organisation (ISRO) is taking long, confident strides to dethrone Russia and claim the record by launching 100 foreign and 3 native satellites in a single launch this February.

With ISRO’s trusted Polar Satellite Launch Vehicle (PSLV) serving as the platform for the launch, the Indian space agency looks all set to give a cutting edge to its image over its competitors, and to come out  as a reliable satellite launch service.

As for how the satellites will be launched into space,  Dr. K. Sivan, Director of the Vikram Sarabhai Space Centre (VSSC) in Thiruvananthapuram, had a convincing explanation to give:

The satellites will be separated from the launch vehicle in different directions. The separation angle and the time of separation will be such that no satellite will collide with the other.

Supposing that a satellite dispatched from the launch vehicle has a relative velocity of 1 metre  per second, it can be calculated that after 1,000 seconds the distance between the satellite and the rocket will be 1,000 metres. The satellite that gets launched first will move at a relatively faster velocity than the satellite that is to be launched next. This difference in relative velocities of the satellites will consequently lead to a continuous increment in the distance between the satellites, while the orbit remains unchanged.

Also, it becomes important that the team wait for the disturbances to subdue once the vehicle has reached orbital condition and before the preparation for separation begins.

As for the time, it would take 90 minutes for the vehicle to complete one orbit at an orbital altitude of about 500 kilometres. That gives the team sufficient time to launch all the 103 satellites.

Moreover, the difference of even 1 degree in the separation angle coupled with relative velocity will nullify the chances of collision between any two satellites. The satellites will be injected into orbit at different locations, at different angles, different times and with different orientations.

The launch, scheduled for February, will be a significant event for space scientists, mainly for those in the Indian space industry. If all goes well, which we truly hope it does, ISRO will ultimately garner the attention it requires for its expansion.