John Schilling wrote:
"Allen Thomson" writes:

continuous thrust = 1 kN, ISP = 10,000 sec
(= 100 km/sec Ve) and a total run time = 1 megasecond
or greater, preferably getting toward 10 Ms.

they can make you up a cluster of high-power ion thrusters
that deliver the sort of performance you are looking for,
without even stretching the state of the art.

Could they really? That's excellent news.

And yes, the ion thruster array will be heavy (kiloton)

Apparently you have a specific design, or design in mind.
What, in general, are you thinking about?

and expensive (gigabuck),

A pittance. I'd be happy to fund out of beer money.(*)

but unless you're invoking magic the power supply will be
heavier and more expensive, so no worries there. If it
really matters, I suspect the second gigabuck could shrink
the mass down to a hundred tons,


Ok, so we're up to a few gigabucks for a 1000 tonne thruster and
a somewhat smaller power supply.

I didn't think this thing would be possible at all, but you've
given me hope. Please continue.

but anything beyond that is going to be *really* expensive.

Like a hundred gigabucks?


(*) Well, actually, my beer funds are a little low at the
moment, but NASA should be happy to pick up the difference.