A big part of the success SpaceX has had since it was founded, in 2002, by Elon Musk is due to the success that has had one of its rockets: the Falcon 9. This rocket has been so successful thanks to the innovative system developed by SpaceX to reuse its rockets, and therefore reduce the prices of space travel.
Overview of the Falcon 9
The Falcon 9 is a two-stage reusable rocket, designed and built by SpaceX. This rocket is designed to send to space satellites, supplies for the International Space Station, people… in a reliable way, as, even if two of its nine engines failed, it can also arrive in orbit.
The Falcon 9 is the first reusable orbital-class rocket ever built. Reusability allows SpaceX to reflight the most expensive parts of the rocket, which reduces, as we will see later, the cost of space travel.
This rocket has a height of 70 metres and is almost 4 metres in diameter. The first stage of the Falcon 9 has 9 Merlin 1D engines. The Merlin are a family of rocket motors, developed by SpaceX, which are also used by the Falcon Heavy. The 9 Merlin 1D engines create a thrust, at sea level, of 7 600 kilo-newtons (1 700 000 pounds).
Once the first stage is separated, which lands another time using 4 deployable landing legs to be reused in the future, the second stage of the Falcon 9 enters the scene, which has an only Merlin 1D engine, modified to operate in the vacuum. This engine can be turned on and off some times, in case of being necessary to carry the payload to different orbits.
The nine engines Merlin 1D of Falcon 9’s first stage are organised in an octagonal structure, with a Merlin 1D at the centre. We name this structure octaweb, and it is vital for the rocket’s first stage, and for its general functioning, which affects the payload capacity. In earlier versions of the Falcon 9, this rocket had also 9 Merlin 1D engines, but they were organised in rows of three. The octaweb reduces the height and weight of the Falcon 9, which simplifies its design and assembly. In the last instance, it lets him carry more material to the Earth’s orbit, and reduces the costs of sending material to space.
Cost reduction of space travel with the Falcon 9
The Falcon 9 was the first reusable rocket to reach orbit. Reusing the rocket allows the most expensive parts of the rocket to be recovered, which reduces the price of sending material to space. During the four decades that followed the Apollo missions, the price of sending one kilo of material to orbit was about 10,000 dollars, as the rockets weren’t reusable. In contrast, since the Falcon 9 was put in operation, this price has fallen drastically. Nowadays, and thanks to the Falcon 9, the price of sending one kilo to Low Earth Orbit (LEO) is 2,000 dollars.
As it can be seen, the reusability of rockets makes space a much more economically accessible place. Nowadays, only the first stage of this and other reusable rockets can be recovered. Therefore, we can expect that, when we will manage to make the second stage also reusable, the prices of sending material to space will be reduced even more.
But this one isn’t the only way to reduce the prices. We put for example SpaceX, a company that spends annually, keeping in mind the construction of rockets, the workers’ salary, and more, about 1,200 million dollars. In the case of launching 30 rockets per year, SpaceX would have to charge 40 million dollars per launch to balance out the expenses. But, if the frequency of launches was 300 per year, what it would need to charge per launch would be 4 million dollars.
So, the key to be able to reduce to the tens of dollars sending a kilo of material to orbit, what has to be done is to increase drastically the frequency of annual launches.