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 that launched the Apollo mission carried 770,000 liters of kerosene, as well as liquid oxygen as an oxidizer), so researchers have long been exploring alternative options to rockets, such as space elevators, kinetic launch systems, or a railgun (essentially, a huge catapult).

Work on the latter is currently underway in China. The idea of the system is to accelerate a spacecraft 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 faster than the speed of sound.

The Scientific Research Institute of Aircraft Technology of the China Aerospace Science and Industry Corporation (CASIC) has already built a two-kilometer test track in Datun, Shanxi province.

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

Another issue is that, for example, railguns launching fighters from the aircraft carrier USS Gerald R. Ford 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 require a staggering 50,000 MJ (and the spaceplane to be used in the future will weigh at least 10 times more).

So, to operate such an electromagnetic cannon, an atomic power station will be needed to generate gigajoules per second, and a completely new supercapacitor will be required to store energy. (The Dresden High Magnetic Field Laboratory Hochfeld-Magnetlabor Dresden has the most advanced capacitor battery, capable of withstanding 50 MJ, which is a world record, but this is insufficient for the railgun).

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

Source: South China Morning Post (via New Atlas)