"Clan Witherspoon" wrote:

 > The question then becomes whether said fuel depots are possible IYTU.
If the jump drive requires a
 > gravity well as a beacon, then fuel depots become service stations
surrounded by networks of high
 > strength gravity generators.

Another interpretation: the gravity well doesn't act as a beacon, but a
target to re-enter normal space. The bigger the object the easier the
target is to hit. It may not be possible to aim for planet size targets,
but you could try for a set of co-ordinates and hope something is there...

'Empty hexes' may not be empty.
Recent microlensing surveys and other extended astronomical observations
suggest:-
- There are as many brown dwarves as stars.
- There are at most one-quarter as many Jupiter-mass or larger rogue
planets.
- There are at least half as many Earth-mass or larger rogue planets.

In game terms, roll based on local density modifiers:

Amended T5 Extended System Contents Table
Extra Galactic= 4 or less (on 3D)
Rift= 3 or less (on 2D)
Sparse= 2 or less (on 1D)
Scattered= 3 or less (on 1D)
Standard= 4 or less (on 1D)
Dense= 5 or less (on 1D)
Cluster= 10 or less (on 2D)
Core= 16 or less (on 3D)

If you get a result saying something should be there, roll 2D:
4 or less = Earth mass (or larger) rogue planet
5-7 = standard star system
8-10 = brown dwarf (may have satellites)
11 or more = Jupiter-mass (or larger) rogue planet

 > If artificial gravity doesn't work, then the search for rogue planetoids
 > becomes a major project for both military and economic reasons - which
 > sounds to me like one hell of a budget.

Regardless, there will be portions of the Scout Service and Naval budget
apportioned to astronomy
over and above commercial and academic efforts. Accurate position and
motion information for stars
and in-system objects is valuable, let alone other characteristics
(spectral type, composition, etc. etc.). Traffic control and system
defense are other important considerations.

At Traveller tech levels, observatories using the local star at a
gravitational lens should be easy to set up. Yes, you are 500+
astronomical units from a Sun-size star. But you could get some very
high resolution images (sub metre resolution at ten light years...)

https://arxiv.org/ftp/arxiv/papers/1604/1604.06351.pdf

 > So what should be the value of information?
It varies, the same as it was for long-distance merchants prior to the
advent of rapid communications.How well can risk be buffered by
contracts and insurance?Are there social engineering options that can be
used to maximise profit? Are they legal?

There is a good discussion in GURPS:Traveller 'Far Trader' about this
topic as well as shipping considerations and thoughts on interstellar
economics.

 > Realistically, fusion could make a bit of hydrogen last quite a while.
 > Since it's been my impression from Classic that power plant fuel got
used up by manuvering,
 > this means that m-drives are add-ons to the power plant and what
would be a fuel efficient process
 > gets used to provide raw plasma for thrust or super-science gravity
generators on mutated steroids.

Yes, Traveller fusion plants are terribly inefficient as written and
remained so
for compatibility's sake.
Best case in Megatraveller is TL 15 fusion at 0.016% fuel energy
available as power.
Traveller: The New Era (TNE) is a little better at 4.3%.
Lower tech levels are far worse.

The fuel can't be used as a rocket; you can't get the canonical
multi-G-hour thrust with either
the standard or relativistic rocket equation even with the Megatraveller
fuel rate.

Traveller m-drives must convert the fuel directly to energy, per E=mc^2,
which is used to generate
momentum and kinetic energy to push the ship along. Call them impulse
drives ;-)

(As a bonus, the near-c rock problem goes away if you invoke
conservation of energy and say hydrogen is the only fuel for m-drives -
you can't carry enough fuel to push a payload to high fractions of c,
but several percent of c is still bad enough and reachable).

Whatever the process is allows the multi-terawatt waste heat to be
radiated without a big explosion.
I think a reasonable handwave is neutrino radiation, or some other
weakly interacting particle.
Which has the bonus effect of enabling directional stealth and giving
ships a reason to carry neutrino detectors.

 > So I would feel confident saying that space stations (and other
things that need power
 > and not m-drives - and probably throw jump drives in there too?) use
in a year what an equal
 > power plant on a ship would use in two weeks.

Depends on which rule set you use, and how efficient a bare fusion plant is:
Megatrav power plant with the numbers above is 3066x worse than 50%
efficiency.
TNE power plant is 11.6x worse than 50% efficiency.

Space stations need station-keeping propulsion, so they will have very
small m-drives; 1 G-hour is a delta-v of 36km/sec, which is huge
compared to the 45m/sec/year required to keep geosynchronous satellites
in position (for example).

If we say that magic radiators are an integral part of the m-drive, they
are still attractive for planet-based power stations; you could have
them on a giant barge type arrangement which would make them proof
against seismic events, for example.

Rob O'Connor