On 6 May 2020 at 10:27, xxxxxx@gmail.com wrote:

> A question that some of the earlier versions of the game never really
> discussed...
>
> If you have a 1G manouver drive, how do you lift off of a 1G planet?
>
> And noting that many planets could easily have upwards of 1.3Gs, even
> the nicely habitable ones, this is kind of important.

The answer the folks who gamed where I was living back then used was
"you don't". That is, if you don't have a 2G manuever drive, you
don't land on planets with a 1g or more surface gravity.

> And if you are going to get close to higher gravity planets, do you
> really need a massive manouver drive?

Not really. As long as you mantain something close to orbital
velocity you can get away with any drive that provides more thrust
than the atmospheric drag you are encountering.

> There's also the question of how humans survive on high G planets (or
> really low G planets) when the TL of the planet is not sufficient (or
> perhaps the economy/government not sufficient) to support a constant
> AG field in all residences...

Humans should be able to survive just fine even on 2g planets (which
can't be generated on the standard tables anyway).

Some people would have problems. They'd either die or move. Pregnancy
could be a problem. But it's not that different from living at high
altitudes on earth. There are health problems but you adapt, move or
die. after enough generations, the locals are fine, visitors may have
problems.

Low grav we are still not certain at what point the problems would be
serious (if you want to be able to leave). Nor at what point things
could screw up pregnancies.

But I'd guess that 0.5 to 1.3 g are probably "good enough".

> (Really, in assessing how good a planet would be to live on, before
> you have the tech and power resources to ignore all the constraints,
> one should look at water, clean air, radiation, atmospheric gas mixes,
> atmo partial pressures, and gravity... and no Traveller system
> building I've seen does that)

If you aren't treating the place as a shirtsleeve environment, then
you can ignore most of those. If there's any significant water, it
can be added to what you recycle. And recycling works pretty well
even at our TL. Even better as you scale things up.

Same goes for air. If there's any significant amount of oxygen,
you'll get along fine. Heck, given fusion power (or even old
fashioned fission) you can extract oxygen from *rock*.

If the air is too nasty, or too low (or high) pressure, you can live
in domes or the like. Or underground.

If radiation (from the star) is too bad, underground again.

Digging *big* caverns is easy with nukes. With nuclear dampers, it's
easy to decontaminate them, though the tests in Nevad show that
there's not that much to do anyway (most of the really radioactive
stuff gets buried with part of the ceiling collapses into the pool of
molten rock at the bottom of the chamber)

If you can breathe the air, or get by with just a filter mask or a
bit of extra oxygen, then living on the surface is doable.

> (Also, how does this change once you drop below AG tech? I'm guessing
> everything before that needs lots of propulsive power).

If there's a decent atmosphere, then landing isn't a problem. There
are lots of ways to make getting into orbit cheaper. Catapults/mass
drivers, Lofstrom Loops,  laser launch systems, the list goes on. and
all of those don't require insane engineering or materials.

> I suppose landings on higher G planets also require an ability to
> cope, but you can sometimes use aerodynamic streamlining or partial
> streamlining and your orbit/attitude to mitigate (I think... not being
> an astronaut or pilot... not sure). But the getting back up is a
> harder thing.

> Or should most starports have assistive launchers (and what would that
> mean for ship design - a standard underside with attachment points)?

This is one of the reasons that highports exist. Ships that have a 1g
drive can dock there and load/unload cargo. The cargo and passengers
get to the surface using shuttles that have a good enough drive.
--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com