Launching Ramp

Electromagnetic propulsion was reported in articles to commonly achieve acceleration in the range of 1K G's. I recall an article in the late 1980's that a university test model accelerated an aluminum bicycle rim to over 230mph in the space of 31 inches. I'd bet you could lengthen the tube and lower the power and achieve a 3-5 G launcher.

Provided you had enough power generation, you could theoretically launch greater than one payload per minute. The sheer VOLUME of launch capability would be daunting. It would far surpass the payload launch rate of the entire current global space launch industry. (Although some of the really large orders would still need rockets.)

I still think simple ablative heat shielding on the leading edges of the payload containers would enable overcoming atmospheric heating issues, and avoiding using vacuum woud reduce costs, as well as unnecessary shock on the payload when the craft transitioned from an evacuated tube to the open atmosphere on launch.

Also, an electromagnetic system would only have one moving part, basically. The payload.

Dan

Cannons don't achieve speeds any where near the mach 25 needed for orbit. A
"Army 45" fires at less than mach 1, as does any gun that can be silenced,
else the sonic boom would make the silencer useless. Guns are ultimately
limited by the speed of the gas particles, which must bounce off the back of
the projectile to give it momentum. Powder burning at 3000 K, considering
(1/2) m v (squared) equals (3/2)k T (which is kinetic theory of gases),
gives its gas (or plasma) particles only a few thousand miles per hour
(perhaps mach 4 or 5). So there is no hope for a gun to shoot from Earth to
space.

> Of course, if a magnetic catapult provides the "first stage" for
> launching a bean can-sized satellite, how does one shield the mission
> electronics from EMP damage?
>

Since you're planning to launch can-sized satellites, why not use a "gas
catapult" - a cannon? As far as I remember, technology for launching small
payloads from cannons to a distance of tens of kilometers exists since WWII
(or maybe WWI). It is very brute-force, kind of antique, but it is also far
easier/simpler and probably cheaper to build. And it would avoid EMP damage.

> Colin Keizer

Lucio Coelho

.