On Wed, Oct 01, 2014 at 08:07:01PM +0100, Timothy Collinson wrote:
> Of course, the newspapers love those stories where a broom cupboard
> (closet) has been turned into an 'apartment' in London and selling
> for some ridiculous price.

Yes, I do know someone who rented such a space while in London.  Room
for one single bed with one large shelf about a metre above the bed.

> There's a table for non-orbital stations, orbital stations, geosync and
> geostationary.  I'm working on a geosync one so the line reads:
> M-Drive percentage: 0.75
> M-Drive cost (MCr/ton) 0.5
> Thrust 0.5G
> (page 5)

Ahh, thrust 0.5G.  For station-keeping purposes that's a staggeringly
enormous acceleration.  To put it in perspective, Earth-centered
geostationary satellites usually have delta-V needs less than 60 m/s
per year.  That is, an average acceleration of 0.0000002 gees.  It's
that high mainly to keep the satellite in a fixed sky position
relative to Earth so that ground-based antennas don't need any
steering at all.

In practice it's done in shorter bursts of greater acceleration, with
peak accelerations varying between 0.0001 and 0.01 gees.  The ISS in
much lower orbit is periodically re-boosted to account for traces of
atmospheric drag, typically with peak acceleration on the order of
0.003 gees and lasting a few minutes.

To put it another way, the thrusters given in the book would be
capable of carrying out a year's worth of station-keeping maneuvers in
about ten seconds.  It could totally flip its orbit and go the
opposite direction in less than 20 minutes, take up residence around
the Moon within hours, or move to Jupiter in days.  That sounds a
little excessive as a bare minimum design feature for a space station.

The power plant seems likewise ludicrously large.  I don't know about
that particular design system, but 50 MW/dton seems like a typical
sort of average for high-tech designs across a few Traveller materials
that list power outputs.  At 15 million dtons that would put the power
output at about 0.8 petawatts.  That's about 50 times the total power
consumption of human civilization today, or about 50000 times as much
per person.

I'm not saying that it's wrong, just that it's extremely large to the
point where I'm having trouble thinking up how even a small fraction
of it would be used up in the routine operations of the station.

I guess one answer might be "it isn't", and 99.99% of the power plant
goes unused 99.99% of the time.  The remaining 0.01% of the time might
be periodic drills to ensure that it actually works at full capacity
for some unspecified emergency.  Maybe vaporizing a moon or two that
have inconvenient orbits ;-)

- Tim