Dr. Ranjan Moodithaya ignited a flame of curiosity in all of our minds
We were truly fortunate to have had the opportunity to listen to Sir, being a renowned
expert in the field of Acoustic Testing at the prestigious National Aeronautical
Laboratories.
From 20 years of acoustic testing of more than 100 vehicles to being a major contributor
to the designing and modeling of the various segments of the Chandrayaan-3, Sir has
been constantly pushing the boundaries of innovation and paving the way for
breakthroughs in aeronautical acoustics.
Sir began by explaining to us the very basics of sound, how it is a pressure wave, how
the range of decibels of sound really matters in satellites and how a sound of 0 dB is
something almost inaudible, like a leaf falling.
In Launch vehicles, the 10-15% of energy which is formed due to the heat , is the
source of generation of the noise which can break any gadget. This calls for the need
of Acoustic Test Faculty.
The interesting way of testing the vehicle of Chandrayaan 3 for its strength against the
acoustics waves, with 120kW of acoustic power built to generate the noise, is truly
captivating!
Sir then went on to explain the various parameters like the frequency, volume, etc.
which are the major factors required in the testing.
These tests go on for periods as short as 1 and half or two minutes which is the actual
time required for the vehicle to leave the atmosphere.
The calculations have to be so precise that even a small screw should not be loose.
It was fascinating to know how a period of a minute or two is so crucial. In these few
seconds, the vehicle either breaks or makes it.
The various space vehicles, like the PSLV, GSLV, GSAT, INSAT and many more and
their numerous parts have to endure high and low temperatures and pressures,

vibrations of certain frequencies, and a lot more. The Acoustic Tests safeguard them.
Ultimately, the multiple failures led to the successful building of a momentous space
vehicle, the Chandrayaan 3.

Sir’s articulation and passion for his work were not only engaging but also inspirational.
Sir has been a guiding light, pushing the boundaries of innovation and paving the way
for breakthroughs. Sir’s legacy, will continue to inspire generations to come. Lastly, we
acknowledged the efforts of Sir VPD for having invited such an eminent personality.