This has been discussed before but to summarize, it doesn't work that way. I realize you didn't say "into orbit" but it is a reasonable place to start. The dis

This has been discussed before but to summarize, it doesn't work that way. I realize you didn't say "into orbit" but it is a reasonable place to start. The disadvantage of 'gun' type launch systems are that they only get one shot at putting energy into the system and they have to do that at low altitude where the air is thickest (the biggest impediment to going fast) as a result your space craft leaves the gun and goes into the soup of the atmosphere and burns up[1]. This is a problem with the rail gun as well as hypersonic projectiles that have active payloads have to deal with friction heating and remain functional at the point where they arrive. The secondary problem is the g-force as a function of the acceleration of going from full stop to 7.9 kM/s in say 10 milliseconds. Your basic physics will tell you that is an acceleration of 80 thousand 'Gs'. If you are launching a payload you need a container that can not crush its contents. Of course all that air resistance will bleed off energy/speed so you actually have to start much faster than 7.9 km/s, as much as 10 - 12 km/s to "coast" into orbit. Now you're over 100,000 Gs to start. [1] This is not unlike shooting a bullet into water (other than water has higher viscosity and the bullet has a lower velocity) but the effect is the same.