A new African altitude record was set by four South Africans for amateur rocketry.
The Karoo, South Africa – The launch took place in the Karoo on 3 August after having received flight clearance from the Civil Aviation Authority. For decades the race had been on to break the 10 km barrier, and the team from Cape Rocketry managed not only to break the previous record of 9.5 km but pip the elusive 10 km mark at 10.37 km. The rocket was also built using all South African parts – from the propellant to the electronics. The triumphant team members were Dino Marx, Mark, John and David de Bruyn.
Here’s how the launch unfolded:
It was a clear and still morning in the Karoo. On the launch pad stood JR101, just over 2m in length and loaded with 8 kilograms of solid propellant. In a few moments, a countdown to send the 20 kg rocket to Mach 1.8 would begin.
Three! Two! One! A power bank is connected to a transmitter, sending a radio transmission to a receiver next to the launch pad. The receiver floods current through a segment of wire salvaged from a kitchen toaster. Located deep within the core of the rocket combustion chamber, the wire begins to glow red-hot and initiates a preliminary chemical reaction in a precisely orchestrated sequence of events. After what feels like an eternity, white smoke begins to billow out of the graphite nozzle, followed by an intense spike of yellow flames. Within a single second, more than a kilogram of propellant has been burnt. JR101 begins to climb the launch rail, built from a curtain railing just a few days earlier.
“At this point, the wall of sound hits the mesmerised crowd. The magnitude of the unfolding events is hard to comprehend. JR101 is already travelling faster than the fastest neuro-transmissions in the human brain.”
Uncertainly remains. Without meticulous execution, the rocket will be shredded mid-flight. With it’s motor generating over 200 kg of thrust, JR101 is starting to fight the atmosphere. Normally benign air molecules crash into its body. Shockwaves are formed on sharp edges. The paint on the nose-cone begins to bubble. The sound barrier is about to be broken. After 7 seconds the rocket is travelling faster than a rifle bullet, Mach 1.8. is reached – twice the speed of sound. At this instant, JR has more kinetic energy than five African elephant bulls, charging at top speed – more than 2 million Jules.
JR has shed almost half of its mass and only has the momentum to fight its ever-constant foes: drag and gravity. All its stored chemical energy has been converted into velocity. The motor enters its final play: its thrust reduces rapidly, and it ends its burn.
The core of the motor has reached temperatures of over 2000 degrees Celsius. After 45 seconds of flight time, it has exceeded the height of Mount Everest by over a kilometre. Its roar can be heard for kilometres.
“Reality is starting to set in on the ground that the motor has done its job. The rocket was aerodynamically sound. Primal cheering begins. The kind you hear when the Springboks score the perfect try against the All Blacks! It doesn’t happen often, but when it does, it’s indescribable. The crowd begins to quiet as the altitude is readout.”
It’s transmitted in real-time from the rocket via an AIM XTRA, a telemetry system built by David. GPS satellites travelling around the earth are sending electromagnetic signals at the speed of light to the onboard electronics.
These signals are correlated in real-time to produce an accurate altitude, which is transmitted to the ground. It is this complex dance that is distilled into a simple number – altitude above ground. The target is 10 km. Less than this and it’s like drawing against the All Blacks: great, but you will always feel it could have been better.
7 km … 8 km … 9 km … 9.5 … 9.8 … 9.9 … 10.37 km!!!
“Cheering! Embracing! Relief. Elation! Emotions are raw. There is another update almost lost in the excitement – the parachute has been deployed! Now the chase is on to track JR and retrieve it.”
The team and a few supporters head off in a convoy of 4x4s along a dusty gravel road in the direction of the last received GPS coordinates. Two members of the team are on the back of an appropriately named Karoo edition Mahindra bakkie. They are using a Yagi antenna to get a clear radio signal.
Driving for 15 km the convoy can go no further and disembarks to walk the remaining distance on foot. The rocket has now landed, and with its last position loaded onto phones, the scouting begins. Like an adult Easter-egg hunt, everyone is hoping to be the first to spot JR.
We should now be less than 100 meters away. “I see it!” someone shouts. We rush over to inspect. Except for blistered paint on the nose-cone and a few bent fins from the ground impact, the rocket is intact.
Complete success!
The group returns to the farmhouse, triumphantly. It’s late afternoon, and time for a braai!
A YouTube video documenting the events of the launch is available on the Cape Rocketry
channel here:
by 
You deserve a case of Bells
Good day,
Unfortunately this article is inaccurate and misleading as to the claim as to “breaking the South African record”.
Although there has been media coverage and a television interview, it is unfortunate that we have to correct the facts.
We have on record, an amateur rocket launch dating back to 1965 that exceeded this altitude, as well as other record attempts that surpasses the 10km altitude.
The current altitude record for an amateur built rocket in South Africa is 32km.
It is most unfortunate that the group failed to research their claim, as there are numerous launches exceeding this altitude already registered with Rocketry SA.