Following a full day session of talks and demonstrations at Grinling Gibbons Primary School today, I realised a few things about children. First, they are all amazed by ‘Space’. Space, the abode of aliens, the kingdom of stars and moons, the theatre where galaxies and nebulae swirl in astronomic poetry; space the final frontier. Second, they are curious to find out about what lies out there, about planets, moons, stars and other celestial bodies. Third, their inventiveness and resourcefulness in building mock rockets is astonishing. They have the drive, the passion to explore. This in turn feeds into their creativity and imagination. It was a pleasure to watch them put together these rockets from scraps and bits and bobs. It was an even greater pleasure to answer their many questions about space.
I firmly believe that the urge to look up to the sky and ponder upon the sun, moon and stars is an intrinsic feeling in all of us; at least in all children. This urge might recede or disappear as we grow older, unfortunately. If we know how to nurture it in children it might become a life-long passion to study the sky and learn about astronomy and the other related, and equally fascinating, subjects such as astrophysics and cosmology. Their questions varied from the number of planets in the solar system to how the Space Shuttle is prevented from catching fire upon re-entry in the atmosphere. They had lots of interesting questions but their main task, however, was about building their own rocket. Even though most of their model rockets would never be airborne, they had the essential qualities of being aerodynamic, of having a propeller of some sort and of being able to carry passengers. The students had a grasp of the basics of how a rocket should be. If I had had a go myself I would perhaps build my favourite rocket: the mighty Saturn V.
The Saturn V rocket is the first and, to date, only rocket to have taken us to the Moon. This is the furthest we have been so far in our manned exploration. The beauty of the Saturn V lies in its ingenious design, its phenomenal power and the series of critical missions which have been made possible thanks to the legendary rocket. Saturn V flew the astronauts who became the first men to walk upon the Moon. In total, it launched 24 astronauts to the Moon. With a mass of about 3 000 tons and measuring a staggering 111 m in height and about 15 m wide, it is truly a magnificent rocket. It is as yet the most powerful rocket ever built in terms of the amount of load it could lift into space. On the 9th of November, it will be 45 years since Saturn V was launched for the first time. Sadly, we haven’t seen anything more impressive yet than Saturn V in terms of rocket or launch vehicle that can take humanity to the Moon and beyond. Other rockets, such as the Atlas V which launched the Curiosity rover to Mars, are special in their own right but nothing surpasses the engineering icon which is the Saturn V.
It is one thing to able to launch something and watch it fall back to the ground. The adage that ‘what goes up must come down’ would shy away in the face of the Saturn V (and of all other rockets that can escape Earth’s gravitational pull, for that matter). The point is that Saturn V was powerful enough to leave the gravitation pull of the Earth. To have a sense of what that means, let’s think about jumping off the ground. It seems easy enough an exercise to jump. But to jump with enough momentum so as to not come down ever, that is something else. To be able to do so, we need to jump up at a speed of about 11 km per second! This is equivalent to 40 000 km per hour. If you jump off the ground with that speed then you are certain not to fall back down. Anything launched with less than that speed will not be able to escape the Earth; they might fall back down or at most remain in orbit around the Earth but still be within the pull of Earth’s gravity if their propulsion is cut off. That speed at which one can escape the pull of gravity is called, simply enough, the escape velocity.
Of course, rockets are not launched at that extremely high velocity. We should understand that it is possible to leave the Earth’s pull as long as we keep the propulsion on. A rocket launched at less than the escape velocity will have to keep powering its thrusters to carry on moving upwards, otherwise it will fall back to the ground or, perhaps, reach a state where it starts orbiting the Earth. It needs constant propulsion in order to keep moving upwards and away from the Earth. However, if it were launched at 11 km per second then it will already have what it takes to escape the Earth’s pull. In this particular case, the rocket can switch off its propulsion and it will keep on moving upwards at that escape velocity.
The escape velocity on the Moon is much less than on the Earth. What that means is that it is easier, relatively speaking, to leave the pull of the Moon’s gravity than it is to leave the Earth’s. The escape velocity depends on a couple of variables: the mass of the planet (or body) we are launching from and the distance from that body’s centre of gravity. The further away we are from the ground, for instance, the less the escape velocity and the easier it would be to escape the gravitational pull. The more massive the body, the greater the escape velocity and the harder it would be to escape from it. Jupiter’s escape velocity is about 60 km per second, for example, while that of the Moon is a mere 2.4 km per second. Please note that, in all instances mentioned here, the escape velocity I’m referring to is the one relative to the surface of the planets or moon.
Hopefully we will not have to wait too long before we have another suite of powerful launch vehicles such as the Saturn family of rockets of which Saturn V is the flagship. The Space Launch System currently being designed by NASA should be a great successor to Saturn V. The legacy left behind by Saturn V can never be underestimated. Let us reflect upon the fact that without Saturn V, we, as a species, would still be limited to the Earth’s domain and would not have had the privilege to set foot upon a different world altogether. Never before, in the history of our race, had we said that we come in peace for all mankind. For all mankind. Any other exploration prior to the moon landing were in the name of either religion or nationality or some other egocentric and inward looking pledge. For the first time ever we came in the name of all humanity. This, for me, is a most humbling thought and one of the most extraordinary achievement of the whole human race. And it was all made possible thanks to the superb Saturn V.