India reaches for the stars...We should too

Wednesday, 31 July 2019

Cricket is an uncomplicated game from a mathematical point of view. The bowler has a simple task, which is to hit the stumps. He does a run-up to build up overall velocity, whirls his arm around to build up more velocity while taking aim, and lets fly.

Assuming there is no batsman, a good bowler will probably have a 99,99% record of hitting the centre stump full toss. A batsman introduces mathematical uncertainty into the game. The bowler will compensate for this by spinning the ball or bouncing it. The age of the ball will affect its speed and its bounce, as will whether or not the stitch hits the ground and so on.

Now try to picture the game differently. Imagine that the bowler has to run up to a spinning merry-go-round, jump onto it, and bowl to hit the stumps. Then imagine that the stumps are also on a merry-go-round, also spinning around.

Finally, imagine that both merry-go-rounds are attached to Ferris Wheels.

If you can picture a bowler running up to the first Ferris Wheel, jumping onto the merry-go-round and bowling to hit the centre stump while the stumps are also spinning and rotating, you will immediately understand what’s involved in landing on the moon.

Fifty years ago this month, July 1969, I was sitting in my parents' flat in Essack's Building, Sparks Road, Overport, in Durban listening to the English Service of Radio South Africa (as SAfm was known then) carrying live audio of the Apollo 11 moon landing.

Think about our imaginary cricket game with the moon as the stumps. The moon at its closest point to earth is 356 500 km away, but at its furthest is 406 700 km away. The moon is moving around the earth at a speed of 3 863 km/h.

Our bowler on our merry-go-round is the spacecraft on the Launchpad. He is rotating at 1 180 km/h. His run-up, the launch of the rocket into orbit around earth, takes 12 minutes.

Like our bowler whirls his arm around to build speed, the spacecraft whirls around the earth with gravity acting like the bowler’s arm. When he lets go of the ball by firing a final rocket, he releases the ball at 38 946 km/h.

It will take our spacecraft 3 days to cover the 400 000 km to the moon. But the moon itself is moving sideways at the same time. So our bowler has to plan to hit the stumps where he expects them to be.

Imagine if the calculation is off by 15 minutes. The moon will have moved about 1 000 km away in that time. To turn around a spacecraft travelling at 38 946 km/h requires a massive waste of fuel – more fuel than the spacecraft is carrying.

How then does our spacecraft slow down when it gets to the moon? It fires a small propulsion engine to get in close enough to be “caught” by the moon’s gravity. Again, if the calculation is off, the craft will either miss and zoom off into space, or crash into the moon.

That, dear reader, is the triumph of the moon landing 50 years ago. The US spent $25 billion in 1973 dollars on the Apollo space programme (about $153 billion in today’s money), but the true genius lies in the mathematical calculations required to send three people to the moon and to get them back safely.

This month, 50 years after Apollo 11, India launched Chandrayaan 2 – a spacecraft heading for the moon where it will deploy a lunar lander to the moon’s south pole, and send off an explorer vehicle to search for water.

The total cost of the mission is US $141 million. To put this in perspective, the budget to make Avengers Endgame was more than double that amount at US $356 million.

How are the Indians planning to do this without the hugely expensive Saturn V rockets that the Apollo programme used?

To use another cricket metaphor, Indians have always been better as spin bowlers than fast bowlers. As you read these words, Chandrayaan 2 is whipping around the earth for 22 days to build up speed before being released to slingshot to the moon. The elliptical orbit brings the spacecraft as close as 276 km and as far away as 71 792 km. It will fire its engines two more times to increase speed around earth on 2 August and 6 August. On 14 August, it will fire a final burst to leave earth orbit toward the moon.

There are many who argue that India with its high levels of poverty should not be spending money on a luxury like space exploration. I disagree. Space technology has given us dozens of advancements that have benefitted all of humankind. Think of CAT scans, water purification, freeze drying of food, clean energy technology… even artificial limbs from NASA robotics tech.

India’s moonshot costs less than what we are spending on bailing out Eskom. They are looking to the future. We should too.