Catapult on steroids. Chinese railgun will launch crewed ships into space

To deliver astronauts into space requires an incredible amount of fuel (for example, the Saturn V rocket, which launched the Apollo mission, carried 770,000 liters of kerosene and liquid oxygen as an oxidizer), so researchers have long been studying alternative options to rockets - such as space elevators, kinetic launch systems, or a railgun (essentially, a huge catapult).

The latter is currently being developed in China. The system idea is to accelerate the spaceship along a giant electromagnetic launch track to a speed of 1.6 Mach (and eventually up to 5 Mach), after which it will ignite its own engines and leave the Earth's atmosphere, accelerating to speeds that are roughly 7 times the speed of sound.

The Chinese Aerospace Science and Industry Corporation's (CASIC) Institute of Aeronautical Technology has already built a two-kilometer test track in Datun, Shanxi Province.

The railgun, which can accelerate a ship with passengers on board to a speed of 1.6 Mach, must have a length of at least 8 km (and much longer for 5 Mach). The problem is that this will require a large number of electromagnets that will require cryogenic cooling (and therefore a huge vacuum chamber that doesn't even exist in nature), as well as a specific lock for the vehicle to reach supersonic speeds (if the system doesn't work perfectly, a very unpleasant accident close in energy to tactical nuclear weapons can occur).

Another issue is that, for example, the railguns that launch fighters from the USS Gerald R. Ford aircraft carrier use 121 MJ to accelerate the plane to 241 km/h. To accelerate a transport of the same mass to 5 Mach, the Chinese railgun would need an astonishing 50,000 MJ (and the spaceplane that will be used in the future will weigh at least 10 times more).

So, to operate such an electromagnetic gun, an atomic power plant will be needed to generate gigajoules per second, and a completely new supercapacitor will be needed to store energy. (The Dresden High Magnetic Field Laboratory Hochfeld-Magnetlabor Dresden has the most advanced capacitor battery that withstands 50 MJ, which is a world record, but it's not enough for the railgun).

Chinese claim that if the railgun system is successful, it will reduce the cost of launching into orbit to $60/kg (compared to SpaceX, the cost is currently $3000/kg).

Source: South China Morning Post (via New Atlas)