Reply To: General thought on old coal mines.

[Aeronaut]

zapkitty wrote:

I thought ‘less than friendly neighbor’ meant drastically limiting shielding mass…

For the concept that I wandered off exploring the FF cores are the thrusters. But that involves passing the alpha beams through the shielding

The only hazard in that concept would be if you were directly behind the ship… but that would get very unhealthy very fast. Thus the cost of doing business with that design goes up equally fast.

And with the power available with FF we’re no longer at the stage of trying to reach orbit by any means possible.

The MHD research means that FF-powered supersonic jets can be done for far less MWe than I had thought… but there’s a ways to go from Mach 3 to orbit.

Doesn’t the alpha (of helium ions) moving at near lightspeed already pass through the shielding? A central core flanked by the remaining cores would only need about a 1 foot spacer in the front to get all the beams to converge where you want to heat the propellant. In that case, existing “Beware Jet Blast” signage should suffice, unless you want to add an image of Donald Duck getting blown *ss over tea kettle.

What might happen if we approached this from ionizing atmospheric nitrogen for the MHD? That’s the bulk of a turbojet engine’s reaction mass. All the oxygen does is make the fuel combustible.