We have had the distinct pleasure of hosting Sir HS Mukunda, on the 30th of
September, a distinguished personality who has not only graced us with their presence
but has also imparted invaluable knowledge and insights, a luminary widely regarded as
one of the best teachers and researchers in aerospace propulsion that India has ever
produced.

Today’s lecture, which delved into the intricacies of rocket propulsion, was a testament
to sir’s profound expertise and dedication to the subject.
We first began with getting to know the various aspects, and stages of India’s 3 active
operational launch vehicles: Polar Satellite Launch Vehicle (PSLV), Geosynchronous
Satellite Launch Vehicle (GSLV), Geosynchronous Satellite Launch Vehicle Mark-III
(LVM3), and explaining certain why’s and how’s.
Sir explained a few aspects of importance for space launch vehicles such as Structures
which are required for the design of the body of the vehicle, Propulsion which deals with
the required thrust, Guidance, and Control which are crucial to know where the vehicle
has to land and finally Aerodynamics which provides the physics and maths required for
all the other processes.

Sir further explained SSTO that is Single Stage to orbit which aims at taking off and
landing back on the ground successfully. Sir explained the need to break up the
progress into space in stages which is due to the minuscule useful payload.
Sir also gave an overview of the multiple stages of a launch vehicle along with the time
altitude and velocity corresponding to those certain stages.
Sir then went on to explain PSLV which is polar satellite launch vehicle, also called
sun-synchronous and helio-synchronous orbit, and how the satellite passes over any
given point of the planet’s surface at the same local mean solar time which transmits
information such as the weather, vegetation, etc. Sir also elucidated the GSLV
Geosynchronous satellite launch vehicle.

Sir explained an einsteinein idea of general relativity of how clocks closer to a massive
object will seem to tick more slowly than those located further away.
Sir explained the different stages of the PSLV. Sir simplified the complex expression of
specific impulse which is impulse per unit mass. Sir threw some light on the materials
used and the various fragments and parts of the different stages involved. Dealing with
temperatures as high as 3500K and having precision so as to produce about 25atm
pressure in fractions of seconds, Wow!, truly fascinating. Sir then, described solid
propellant, its specifications, and how it burns. Sir also talked about the star-shaped
engine and how the star shape provides a greater thrust in a given burn time due to
greater surface area. We then saw the structure and the functions of the GSLV
Sir emphasized why liquid/cryoliquid propellants are better over solid propellants
because solid propellants don’t provide variable thrust, that is once the fuel is ignited it
can’t be extinguished, which the liquid propellants allow. Sir very well resolved the 2nd

phase of PSLV, the Launch Vehicle control, and the Side Thrust Injection Control
System too. Finally, sir showed us a few launch vehicles and explicated them as well.
Sir also shared with us the precious moments with Dr APJ Abdum Kalam and Mr Satish.
In conclusion, we expressed our immense gratitude to sir, for answering our queries
patiently and for sharing his time, knowledge, and expertise with us. Sir’s wisdom,
experience, and insights enriched our understanding of not only rocket propulsion but
also aerospace and aeronautics, sir’s dedication to the field continues to inspire us all.