It’s not about my dog, this Puli is not barking at the Moon! At first because it hasn’t even born (just in scientists’ brain), and for the second time because the Puli is about to be a space probe. A group is organised – in which I participate as a consultant – where astronomers, physicists and, among many other great scientists, engineers are working for the goal that the Hungarian space probe, the Puli, reach the Moon, what is more, take a few step on it. This is not an easy task, and there is also a chance that we won’t succeed in few years. Of course our work won’t be useless, if we get to the solution of some part-tasks. It’s going to be the part of the Hungarian space research, in which many things can be built in the future. Though we believe we’ll be able to find sponsors, and money won’t be the obstacle of the realization. Furthermore we also believe that with our competence we are suitable for this unusual challenge.
The Moon – first in 1969 – was also reached by man. I’m sure you’ve heard about Neil Armstrong, who was the first human on the Moon. With him Edwin Aldrin also stood on our heavenly companion’s surface, and they returned back to the Apollo spaceship, which was orbiting around the Moon. Meanwhile the third member of the team, Michael Collins stayed in the spaceship. A rocket (like the Apollo spaceship), which is adequate to land on the Moon by man, was developed in one decade. The moon craft, which landed with the Apollo 11, was developed with the leadership of a great Hungarian engineer called Ferenc Pavlics. Of course there were technical preliminaries… Obviously, in few years we can not solve everything by ourselves, we lean on preliminaries, the available developed technical background, but everything else has to be bought. Though the Hungarian physicists have already proved in space research, they were always working for someone else. Now we imagine it in the opposite way: we are going to buy what we need, but what we can we are going to find out and create by ourselves. This is going to be real-Hungarian, like a good Hungarian Puli dog.
We know that the Moon is not really near. Average spaceships, space stations, space shuttles (moreover the most artificial Moons) are orbiting around the Earth, just a few kilometre away from it. Our planet’s diameter is almost 13 thousand kilometres, so these space tools are just right next to the surface of the Earth, around forty times higher, than the airliners. But the Moon’s average distance from the Earth is 384410 km. To take this distance the light, which moves the fastest, needs more than 1 (1,28) second. To the Moon we can put the Earth thirty times next to each other, so our heavenly companion is thousand times further than the most satellite. Moreover it is 30-40 times further the airliners flying above our heads, when they had already reached the travel height. But anyway, how can anything be sent to the Moon? As we know it’s not working like when we carry something on the surface of the Earth. Here, the transportation tools, when they are doing rectilinear uniform motion, are constantly consuming fuel, to overcome the friction and the drag. This is why most people believe that to the motion you need force. In the case of rectilinear uniform motion, the forces effecting the body equalize each other. For example the force which drives a car, equalizes with the opposite directional, but the same volume, friction and braking force. When the forces effecting the body don’t equalize each other, the body accelerates, the velocity vector changes. If the body slows down, it’s a negative acceleration. With ground transportation we can change the direction easily, even when we control a robot by a remote control. In the space there is no friction or drag, but the gravitation works: the heavenly bodies (like the Moon or the Earth) attract the other artificial celestial bodies towards themselves. Attention! This is a huge delusion that there’s no gravitation in the space. The space is full of gravity, because every celestial body attracts the others. Of course it really matters, how close we are to the bodies, because the gravitation increases when we are getting closer to the celestial body. In the opposite way, it weakens when we are going farther; moreover it is inversely proportional to the square of the distance. For example in the case of half distance it’s four times bigger, three times farther, nine times smaller, but in the case of ten times bigger distance it decreases to its hundredth part. The space tools don’t need rocket-drive constantly. The chosen tool is launched by a space rocket towards the appropriate direction and meanwhile we accelerate it to the required velocity – in this way we throw it where we want. If we would like to correct, specify the direction (orbit modification), we use a rocket again. Though the fuel is pretty expensive, and to place it in great distance/height is really costly. So it really matters how we aim the Moon from the Earth, which orbits around the Sun (with the Moon) at 30 km/sec (more than 100 thousand km/h) velocity and its peripheral speed at the Equator is more than a thousand km/h. The Moon orbits around our Earth quite fast too, approximately at 1 km/sec which is 3600 km/h. It also matters how large the orbit modification is going to be before landing. After that, if we want it not knock hard on the surface of the Moon, we have to slow it down before landing and while it’s falling – with the help of a rocket. Since the Moon has no atmosphere, we can not use braking shield.
I’m going to write the details of this story in the future. What you can do now is to contribute to our success, and your name can be launched to the Moon (see: www.pulispace.com )!
Zoltán E. Kovács
Translation by Virág Váczi
Abacus magazine on Mathematics for ages 10-14
This paper is maintained by the János Bolyai Mathematical Association and the Foundation for Children Talented in Mathematics. The 14 sections of this magazine deal with interesting topics and competitions about maths and natural sciences. Founder: Sándor Róka, 1994.
The following articles are the works of Zoltán E. Kovács from the monthly issue of the magazine, and deal with the Puli project and and many related topics in a clear and easy to read style. The articles are only presented in Hungarian, please refer to the Hungarian version of this page for more details.