How India Built Its First Indigenous Rocket — The Forgotten Story of Rohini RH-75
The whole thing started with a question that had absolutely nothing to do with rockets.
One evening, I was reading about aircraft and sound.
You know that strange moment when you see a jet overhead but hear it a few seconds later? I found myself wandering through explanations about how sound travels through the atmosphere, how air density changes with altitude, and how scientists measure conditions high above the Earth.
That was when I came across something called a sounding rocket.
At first, I assumed it was some kind of rocket that made sound.
It isn't.
The name comes from the old nautical term "to sound," meaning to take measurements. Sounding rockets are essentially scientific instruments that briefly travel into the upper atmosphere, collect data, and return.
A simple enough concept.
But then another question popped into my head.
How was the first rocket launch in India actually carried out?
I expected a straightforward answer.
An Indian rocket launched from India.
End of story.
Instead, I discovered something that completely changed the direction of my reading.
The first rocket launched from Indian soil wasn't Indian at all.
On 21 November 1963, an American Nike-Apache sounding rocket rose into the sky from Thumba, near Thiruvananthapuram, under the leadership of Dr. Vikram Ambalal Sarabhai.
The launch site was Indian.
The team was largely Indian.
The rocket was American.
I remember staring at that fact for a few seconds.
If India's first rocket wasn't built in India, then how did Indian scientists learn to build rockets of their own?
That question led me down a rabbit hole that eventually ended with a tiny rocket called Rohini RH-75.
A rocket so small that most people have never heard of it.
And yet, the more I learned about it, the more convinced I became that RH-75 might be one of the most important rockets in Indian history.
Not because it flew the highest.
Not because it carried the biggest payload.
But because it taught a generation of engineers how to build rockets.
---
Before There Was a Rocket, There Was a Vision
When people talk about the early history of ISRO, it is tempting to start with launch vehicles and satellites.
But the story really begins with a person.
Dr. Vikram Sarabhai.
One thing that struck me while reading ISRO: A Personal History by Dr. R. Aravamudan and various historical accounts of the Indian space programme is that Dr. Sarabhai never seemed fascinated by space for its own sake.
He certainly loved science.
But his real interest was what science could do for people.
Weather forecasting.
Communication.
Education.
Resource mapping.
Disaster management.
National development.
Again and again, those themes appear in his speeches and writings.
At a time when many questioned whether a developing nation should invest in space research, Dr. Sarabhai argued that advanced technology was not a luxury. Properly used, it could become a tool for solving real problems.
Looking back today, with satellite television, weather forecasting, remote sensing, navigation systems, and lunar missions, his vision feels remarkably far-sighted.
But in the early 1960s, it was just that.
A vision.
India had enthusiasm.
India had talented scientists.
What India did not have was experience building rockets.
---
Thumba and the Art of Starting Small
To begin learning, India first needed a place to launch rockets.
That search eventually led to Thumba, a small fishing village near Thiruvananthapuram.
The location was chosen because it lay close to Earth's magnetic equator, making it ideal for studying the upper atmosphere and ionosphere.
The early photographs from Thumba have become legendary.
Rocket parts on bicycles.
Equipment transported by bullock cart.
A church building converted into offices and laboratories.
Whenever these images appear online, they are usually accompanied by inspirational captions.
I understand why.
But I also think they deserve a little context.
The bicycle stories are real.
The bullock cart stories are real.
Yet they sometimes create the impression that rocket science itself was somehow simple.
It wasn't.
A rocket motor does not become easier to design because it arrived on a bicycle.
A telemetry system does not become less complex because it was assembled inside a former church building.
The photographs tell us something important, but not what many people think.
They tell us that infrastructure was limited.
The engineering challenge remained enormous.
---
Why India Used Foreign Rockets First
The first launch from Thumba used the American Nike-Apache sounding rocket.
Later came French Centaure rockets.
Then Soviet M-100 rockets.
At first, I wondered why India didn't immediately start building indigenous rockets.
But the more I thought about it, the more reasonable the decision seemed.
Imagine trying to build an aircraft before anyone has ever operated one.
You would first want engineers to understand engines, aerodynamics, instrumentation, testing, maintenance, and operations.
That was exactly what sounding rockets offered.
A sounding rocket occupies an interesting middle ground.
It is more complex than a laboratory experiment.
Far less complex than an orbital launch vehicle.
Perfect for learning.
Through these launches, Indian engineers learned how to integrate payloads, track vehicles, receive telemetry, conduct countdowns, analyze flight data, and manage launch operations.
Most importantly, they learned what they didn't yet know.
That may sound like a small thing.
In engineering, it is often the beginning of real progress.
---
The Difference Between Launching Rockets and Building Them
Eventually, however, there comes a moment when operating someone else's technology is no longer enough.
You have to build your own.
That sounds simple when written in a sentence.
In reality, it is a mountain of interconnected problems.
A rocket is not one machine.
It is many machines pretending to be one.
The structure must survive aerodynamic loads.
The motor must generate thrust reliably.
The propellant must burn in a controlled manner.
The nozzle must convert pressure into velocity efficiently.
The instrumentation must survive vibration.
The telemetry system must transmit data back to Earth.
The tracking systems must know where the vehicle is.
The launch infrastructure must coordinate everything.
Failure in any one subsystem can end a mission.
The challenge facing India's young engineers was not merely building a rocket.
It was learning how all these systems interacted.
That learning process eventually produced the first indigenous member of the Rohini family.
---
Meet Rohini RH-75
On 20 November 1967, India launched its first indigenous sounding rocket.
Rohini RH-75.
The specifications are surprisingly modest.
The rocket had a diameter of just 75 millimetres.
It stood approximately 1.5 metres tall.
Its launch mass was around 32 kilograms.
It carried roughly one kilogram of payload.
It was a single-stage sounding rocket.
Between November 1967 and September 1968, approximately fifteen launches were conducted.
By modern standards, RH-75 was tiny.
If you placed it beside PSLV or LVM3, it would almost disappear.
And yet size is probably the least interesting thing about it.
What mattered was that Indian engineers had designed it.
Built it.
Tested it.
Modified it.
Learned from it.
Every launch became an engineering lesson.
Aerodynamics stopped being a textbook chapter.
Propulsion stopped being a theoretical concept.
Telemetry stopped being something imported from elsewhere.
Knowledge became experience.
And experience became capability.
---
Newton's Third Law Is Easy. Rocket Engineering Is Not.
Every student learns Newton's Third Law.
For every action, there is an equal and opposite reaction.
A rocket throws hot gas downward.
The rocket moves upward.
Simple.
The equation takes one line to write.
Building a rocket capable of doing it reliably is another matter entirely.
The exhaust gases leaving a rocket nozzle can reach temperatures of several thousand degrees Celsius.
Pressures inside the motor must remain predictable.
Materials must survive heat, vibration, and acceleration.
Aerodynamic stability must be maintained throughout flight.
Instruments must continue functioning despite harsh conditions.
The physics is elegant.
The engineering is messy.
Reading about RH-75 reminded me that technological progress often lives inside that gap between elegant theory and difficult reality.
---
The Propellant Problem
One of the most fascinating parts of the story involves something most people never think about.
Propellant.
When we look at a rocket, our eyes naturally focus on the outer structure.
The real magic is happening inside.
A rocket motor is essentially a controlled chemical reaction.
The challenge is keeping it controlled.
Too fast and the motor can fail.
Too slow and performance suffers.
In the early years of India's programme, scientists and engineers worked extensively on indigenous propellant development.
Among those who played important roles were Dr. Vasant Gowariker and Dr. A. E. Muthunayagam.
Historical accounts from VSSC and studies such as History of Rocketry in India describe work involving natural-rubber-based propellants and later polyester-based formulations.
At first glance, this sounds like a highly specialized technical detail.
It isn't.
A nation that cannot produce its own propellants remains dependent on others for one of the most critical parts of rocket technology.
Developing indigenous propellants was not merely chemistry.
It was capability building.
It was self-reliance in the deepest engineering sense of the term.
---
The People Behind the Story
One thing I appreciate about memoirs such as Mr R. Aravamudan's ISRO: A Personal History and Dr. A. P. J. Abdul Kalam's Wings of Fire is that they make the early space programme feel human.
History often compresses decades into a few pages.
The people living through those years did not experience them that way.
Dr. Vikram Sarabhai appears as a visionary constantly encouraging people to attempt things that seemed slightly beyond reach.
Mr. R. Aravamudan's recollections reveal the practical realities of operating launch facilities and solving day-to-day technical challenges.
Dr. A. P. J. Abdul Kalam appears not as the national icon we know today, but as a young engineer obsessed with learning.
Reading those early chapters, you get the sense of someone who genuinely enjoyed understanding how things worked.
Dr. A. E. Muthunayagam helped establish propulsion capabilities that would become essential in later programmes.
Dr. Vasant Gowariker contributed significantly to propellant research and rocket technology development.
What connects all of them is not genius alone.
It is persistence.
None of them knew where the story would end.
They were not building Chandrayaan.
They were not planning missions to Mars.
They were trying to solve the next engineering problem.
History only makes the path look inevitable after it succeeds.
---
The Rohini Family Begins to Grow
RH-75 was only the first step.
Soon came RH-100.
Then RH-125.
RH-200.
RH-300.
RH-560.
Each generation expanded capabilities and pushed engineers toward new challenges.
The naming convention itself was simple. The numbers represented rocket diameters in millimetres.
But behind those numbers was something much larger.
Confidence.
Experience.
Technical maturity.
The Rohini programme became a ladder.
Each rung supported the next.
---
From RH-75 to Orbit
While reading about RH-75, I kept thinking about something.
The rocket itself was operational for less than a year.
Yet its influence lasted for decades.
The experience gained through sounding rockets eventually fed into larger launch vehicle programmes.
Those programmes produced SLV-3.
And on 18 July 1980, under the leadership of Dr. A. P. J. Abdul Kalam, SLV-3 successfully placed Rohini Satellite RS-1 into orbit.
For the first time, India had launched its own satellite using its own launch vehicle.
That achievement did not appear overnight.
It emerged from years of experiments, failures, redesigns, and lessons learned from much smaller rockets.
The chain continued.
SLV-3 led to ASLV.
ASLV contributed lessons for PSLV.
PSLV became the workhorse that carried satellites for India and many other countries.
Then came GSLV and LVM3.
Then Chandrayaan.
Then the Mars Orbiter Mission.
And now human spaceflight efforts through Gaganyaan.
Looking backward, it becomes easier to see the connections.
The line is not perfectly straight.
But it is there.
And somewhere near the beginning of that line stands RH-75.
---
Why Sounding Rockets Still Matter
At one point, I assumed sounding rockets were simply training wheels.
Something nations used before moving on to bigger things.
That assumption turned out to be wrong.
Even today, sounding rockets remain valuable scientific tools.
They help researchers study the atmosphere.
They support microgravity experiments.
They test instruments.
They provide data that satellites cannot always collect efficiently.
In other words, sounding rockets never became obsolete.
They simply found their place.
---
A Small Rocket With a Long Shadow
When I first started searching for the story of India's first rocket launch, I thought I was looking for a rocket.
Instead, I found a story about learning.
The first rocket launched from India was American.
The first indigenous rocket was tiny.
The facilities were modest.
Resources were limited.
Experience had to be built piece by piece.
And perhaps that is exactly what makes the story so compelling.
Rohini RH-75 was not important because it broke records.
It was important because it taught people how to build things that eventually would.
It transformed rocketry from something India could observe into something India could practice.
When we look at images from the Moon, Mars, or future human spaceflight missions, it is easy to focus on the spectacular moments.
The launch.
The countdown.
The celebration.
But engineering history is often built on quieter moments.
A successful test.
A propellant that finally behaves as expected.
A telemetry system that works.
A young engineer learning something new.
A small rocket rising above the coast at Thumba on 20 November 1967.
Sometimes the most important chapters in history are not the loudest ones.
Sometimes they are the ones that quietly make everything else possible.
RH-75 feels like one of those chapters.
And I think it deserves to be remembered.
Sources and Further Reading
* Gopal Raj — Reach for the Stars
* Dr. R. Aravamudan — ISRO: A Personal History
* Dr. A. P. J. Abdul Kalam and Arun Tiwari — Wings of Fire
* Roddam Narasimha and colleagues — History of Rocketry in India (Acta Astronautica)
* ISRO historical publications
* Vikram Sarabhai Space Centre (VSSC) historical publications
* INCOSPAR and Thumba Equatorial Rocket Launching Station archives
* Technical literature on the Rohini sounding rocket programme and indigenous propellant development
Comments
Post a Comment