China Developing Giant Magnetic Launcher for Hypersonic Space Planes

This should be fun.  First off, you get rid of the whole human support problem in order to apply massive acceleration  which also shortens the launch tube.  Initial launch can certainly be live steam as well so that you are up to sub sonic speeds with that.  The magnetics then takes it up to scram jet ignition speed.

The central purpose is to send real tonage into space using the scram jet for the build up to orbital speed

There will need to be a shield able to handle exit shock from the tunnel and then with the scram jet on you have to gain altitude and speed until actual space insertion.  This is at least well understood and possible.

It is going to be difficult though to properly survive hte initial launch sequence with what needs to be variable loading for a fifty ton object.  rockets can do this, but the Gs are much lower.

China Developing Giant Magnetic Launcher for Hypersonic Space Planes

March 17, 2024 by Brian Wang

https://www.nextbigfuture.com/2024/03/china-developing-giant-magnetic-launcher-for-hypersonic-space-planes.html

China Aerospace Science and Industry Corporation’s (CASIC) plans to build a giant magnetic launcher to propel airplanes up to speeds where they can start hypersonic scramjet engines.

CASIC has built a 2000 meter long low-vacuum track high-speed maglev test facility in the industrial heartland of Datong, Shanxi province. This is able to accelerate heavy object to speeds approaching 1,000km/h (620mph)– close to the speed of sound. China wants to launch a hypersonic space plane weighing 50 tonnes and measuring longer than a Boeing 737. It is part of the Tengyun project unveiled in 2016.

In the coming years, the length of the test line will be extended to achieve a maximum operating speed of 5,000km/h (3100 mph).

If the US magnetic launcher uses 121 megajoules to accelerate to a plane to 150 mph then the current CASIC system would need about 2000 megajoules to get a full sized plane to 620 mph. I would expect they are accelerating one ton or less and using about 100 megajoules or less.

Accelerating to five times the speed (3100 mph) would need 25 times more power for the same sized object. This would mean around 50,000 megajoules.

A regular gigawatt reactor would be making a gigajoule each second. However, the power could be stored in massive capacitors or batteries. A nuclear reactor could charge up massive amounts of capacitors for 50 seconds which would then be discharged for the launch.

The HLD (Hochfeld-Magnetlabor Dresden- Dresden High Magnetic Field Laboratory) has an in-house coil development and production program. The Germans aim is to achieve a field of 100 teslas over a pulse duration of 10 milliseconds. The required energy of 50 MJ is provided by the world’s largest capacitor bank, custom-made for this laboratory.

China would need 2000 of the disk alternators in the US Ford aircraft carrier or 1000 times the capacitor bank of the Dresden magnet lab.

The scale of what China is talking about building seems to be about 1000 times the power of the largest capacitor or electromagnetic launcher. China would need to have some breakthroughs on the technology and the mass production of key systems. It also seems that for this to be worthwhile and practical, China would want to be able to use the giant magnetic launcher with high frequency. The launcher and energy systems would be a huge investment.

The Electromagnetic Aircraft Launch System (EMALS) on the US Ford-class aircraft carrier can accelerate jet fighters to speeds over 150 miles per hour (241 kilometers). Compared to steam catapults, EMALS weighs less, occupies less space, requires less maintenance and manpower, can in theory be more reliable, recharges quicker, and uses less energy. Steam catapults, which use about 1,350 lb (610 kg) of steam per launch, have extensive mechanical, pneumatic, and hydraulic subsystems. EMALS uses no steam, which makes it suitable for the US Navy’s planned all-electric ships.

Compared to steam catapults, EMALS can control the launch performance with greater precision, allowing it to launch more kinds of aircraft, from heavy fighter jets to light unmanned aircraft. With up to 121 megajoules available, each one of the four disk alternators in the EMALS system can deliver 29% more energy than a steam catapult’s approximately 95 MJ. The EMALS, with their planned 90% power conversion efficiency, will also be more efficient than steam catapults, which achieve only a 5% efficiency.

During the 8,157 EMALS catapult launches conducted 2022, EMALS achieved a reliability of 272 mean cycles between operational mission failures (MCBOMF), where a cycle is the launch of one aircraft. This reliability is well below the requirement of 4,166 MCBOMF.