Using old technology for a feasible launch mechanism

[mikkelrj]

Hey spacejunkies.<br /><br />First i would like to thank you for all your contributions to this forum, i discovered it a couple of days ago, and have read intensively ever since, there is a lot of interesting info and discusions going on in here <img src="/images/icons/wink.gif" /><br /><br />Well now to my idea, i dont know if this has been suggested before, but i hope it can give a relevant discussion. <br />There is alot of focus on launch mechanisms that are using magnetic/electric fields to accelerate the payload to a given speed. I think the idea is beatiful, but at this point we simple don't have the materials to sustain the large amount of heat being developed upen release of the launch vehicle. Instead, we could use the boost technology for pushing a launcher to a certain speed, where its own engines would take over. If we imagined drilling a deep hole (several km's) and at the bottom of the hole we have a platform with a launcher mounted onto it. The platform would be connected to a large mass at the top of the tunnel. The large mass would fall in a vacuum chamber, eliminating air resistance, and thereby providing a steady acceleration to the platform. When releasing the large mass the platform would accelerate with aprox. 10m/s². Ultimately the launche vehicle on the platform could be a airbreathing rocket, which have to be accelerated to a certain speed before being fully functional. There you go, a simple ground launcher using technology which have been known for a very long time. I know some of you guys have a lot more experience on this field than me, so please feel free to comment, this is only an idea, and i dont know if this has any practical use.

 

[krrr]

I think one problem is that the resulting velocity would be relatively modest, because it is proportional to the square root of the hole depth. v = sqrt(2*g*h).<br /><br />For 1 km that would be around 140 m/s, for 4 km 280 m/s, for 8 km 400 m/s. <br /><br />

 

[henryhallam]

Actually the velocity is less than that because the acceleration isn't g, it's g(M-m)/(M+m) where M is the mass of the heavy weights falling in the vacuum chamber, and m is the mass of the projectile and platform.<br /><br />You could improve the "muzzle velocity" using pulleys but it's still going to be pretty useless, really. Sorry.