> p.s. How come no one complains about psionics when it's just
> as much magic as 'thruster plates etc '? I always figured
> GDW threw it in originally because everyone "knew" you couldn't
> publish an rpg profitably w/o emulating TSR's 'magic' & 'wizards'
> in (A)D&D. Ergo psionics!
I think it's mainly because it's *obvious* magic.
Thruster plates are presented as scientific devices, which should therefore
follow a scientific basis. No such basis is presented (for obvious reasons)
and so I feel a sense of dissatisfaction. Furthermore, the existence of
such a device leads to various other technologies (such as a simple
energy-creating device) which are absent, with no explanation.
Psionics is presented simply as magic, studied scientifically but not based
upon scientific principles. It claims no more 'legitimacy' than it actually
possesses.
- -*-*-*-*-*-
>>Getting high in the atmosphere does not mean that it will be any easier to get
>>into orbit. There's still a slight problem of achieving 8 km/s.
>
> Yes, but its still easier to achieve 8km/s than 11km/s! (assuming a 1g planet)
If you want to get into orbit, you need a delta-V of 8 km/s. If you want to
get to the moon, you need 11 km/s. It doesn't really matter whether you're
at the bottom of the atmosphere or above it. (Actual figures will vary for
different planets, but escape velocity is always sqrt(2) times orbit velocity.
Getting above the atmosphere is *not* the same thing as getting into orbit.
(You have less friction, but the strength of gravity is almost the same)
On a slightly different note, the surface gravity is not directly connected
with orbit speed. Orbit speed is easily calculated as
orbit speed = sqrt(surface gravity * planet radius).
(Make sure all quantities are measured in consistent units)
A 1g planet will not necessarily have the same escape velocity as Earth.
It would have to be the same radius. On the plus side, many Earth-type
planets will have the same composition, so the size should be about the same
for the same surface gravity.
>>I'd be amazed if a simple alcohol rocket could get 1 km/s exhuast velocity,
>>and even so it would take 200 tons of fuel to get a single person into orbit.
>>Multiply by 20 to get to the moon.
>
> Hey, I never said it would be easy - the ref does have to be kind!
(As a note, this 4000 ton figure assumes the high 1km/s figure, and *only*
a 70 kg person - no spaceship, no suit, etc)
It would be easier if the planet was high-density or low-gravity, and the
moon in question was in a low orbit. Still assuming 1km/s exhaust, but a
planet like Mars (half size, half gravity), and a moon (like Deimos) in
low orbit:
Orbit speed is half that of Earth, ie. 4 km/s. Fuel/payload ratio is
ratio = exp(delta-V / exhaust) - 1
= exp(4)-1,
which is about 50 to 1.
Getting 1 ton (a group of people and hull) to the moon should take only about
50 tons of fuel. Much easier than the case for Earth. If the planet stats
haven't already been generated, it would be a reasonable act of ref kindness
to set up this sort of situation.
> Who said THIS moon had no atmosphere?
No-one ... but it's rather unlikely. A moon would have to be very large to
retain an atmosphere. I'm talking around Mars-sized. That is, about 10
times heavier than our own Moon - which is generally considered especially
large. (The orbital problems also become more difficult, and you need to
worry - a lot - about atmosphere entry to such a moon)
>>Overtaxing the vacc-suit computer would be less of a problem (*especially*
>>at TL15 - hand supercomputers are TL11 stuff), compared to the problem of
>>needing yet more fuel...
>
> The technology to build handheld computers may be there but why would you
> fit one into a vacc suit? All it has to do is control lifesupport, a
> supercomputer would be an unneeded waste of money.
I can think of a couple of reasons.
1) A computer that qualifies as 'super-' to us certainly would not to TL 15
technology. A model/1 (at least!) would probably be about as common as
digital clocks are today. (Glancing around, I see 6 such clocks in direct
view. I have another 2 in my pencil case. All but 2 are parts of a
device that has a different primary function) If you don't like the clock
analogy - I see 4 devices that serve as (at least) 4-function calculators.
2) Necessity. A space-suit needs to be safe. This means being immediately
aware of any problems. Air duration, suit integrity, probably also short-
range comms, thrusters, and various other options. Voice control is easy,
and some sort of HUD (probably holoscreen) would probably be a standard
part of the suit. At this point, it would be extra effort to restrict
the computer to the single purpose of suit/comm/thruster control. If
nothing else, the thruster control should include primitive navigation
software (eg at least equal to ancient TL 12 capability)
- -*-*-*-*-*-
> RE:Timothy Little
> ". . .I'd like to see someone plot a decaying orbit around the moon! No
> atmosphere to slow the guy down means little chance of orbital decay. . ."
>
> I was under the impression that orbital decay occured because of gravity,
> at least for objects short of geosychonous orbit.
There is a slight element of pure gravitational decay, but this is utterly
negligible for anything less than close binary stars, on the scale we are
talking about. Tidal stress can actually cause objects to 'decay' outwards,
as the angular momentum contained in the spin of an object is transferred
to the orbit. Gravitational radiation (as yet undetected) can be completely
ignored.
The reason satellites fall out of orbit is due to drag from the atmosphere.
There is no clear boundary that divides 'space' from 'atmosphere'. Slight
drag from the almost-vacuum drops the object into a slightly lower orbit,
where the gas is a little thicker, exerting more drag, ...
> What about the contragrav units on the ship? Are they functional? The
> stuff on the ship can become very important. . .I doubt it's completely
> destroyed, since they seem to have landed safely.
Any contragrav unit which is repairable, is worth much more than its mass in
gold in this situation! I'd much rather try to build a power supply for a
grav unit than try to reinvent extremely dangerous rocket technology, and
produce tons of fuel for the explosive contraption thus constructed.
- -*-*-*-*-*-
Here's a thought for the total munchkin powergamer terrorists among you:
It is easy to build a 6G unmanned spacecraft, for very little cost. Now,
set this up about a parsec outside a star system, do a simple orbit
plot of some target object (say an unihabited planet in the same system as
a planet of 9 billion people), and start up the engines. In just over a
year, it will hit your target at 99.88% of the speed of light, causing
extensive disruption of the planet. The good part is, if the system
defence can spot an object at 1 billion km, they'll have just over 4 seconds
to react before it impacts. Besides which, there's not really anything they
can do to deflect it.
"The next one is aimed at *your* planet. Accede to our demands, or ..."
- --
Tim Little