## 2015-05-05

### Raising Ship By Raising Shields

Y'know, shields are wonderful things.   One thing we have never seen anyone use them for, however, is lift-off.

Inspired by Buckminster Fuller, I was thinking the other day of using shields in a Cloud Nine fashion, making a big enough shield bubble to let minor air temperature changes float the ship.

But, vacuum would work better, even if it was a bit more taxing to the shields due to pressure difference.   Start with skin-tight shields and then expand them outward laterally and upward, leaving a vacuum in their wake.  At a quoted lifting force of 1.28 grams per liter (based on the displaced mass of air at sea level), my math suggests that a 700,000 tonne starship like Voyager could be lifted by a vacuum volume of 546,875,000 cubic meters.

That's a sphere of 1,014 meters in diameter, or a hemisphere of about twice that depending on how you fit the ship in exactly.

We have seen the Enterprise extend shields to protect a ship at a stated range of five kilometers, IIRC, so in principle it might be doable.  And that doesn't even bring subspace mass-lightening into the equation.

Certainly it would be an interesting way to soft-land a starship rather than crash*, assuming you can figure out how to drop the shield gently on touchdown.   I can't imagine a sudden shut-off, producing a mad rush as air tried to fill a kilometer-wide void, would be healthy for any ship that needed to be using the technique in the first place.

(* In the case of the E-D saucer, of course, it seems this wouldn't be useful as the shields did not seem to be online. )

Anonymous said...

If you can steadily expand the shields you can probably steadily contract them as well, that would work for landing.

Guardian said...

Naturally, but the concern I was pointing out (valid for any point of the flight, really) is graceful shutdown. A parachute, for instance, is simple and dumb once deployed successfully, as any good passive system should be. An active system like the shield idea has less graceful failure modes.

One can imagine, then, a ship without landing legs trying to set down and fritzing the shields while they are still rather expanded (so as to prevent too big a thump from too high a velocity), causing a veritable implosion of local atmosphere. Bystanders would consider that altogether quite rude. :-)

Lucky said...

Your reasoning for not liking the idea seems like it would apply to blimps, hot air balloons, dirigibles, and any other airship, and that leads me to question if it is a valid argument?

Using the shields in such a way would simply be creating a vacuum airship after all.
http://en.wikipedia.org/wiki/Vacuum_airship

Guardian said...

Blimps and balloons and such don't land with their bag on the ground.

Lucky said...

You seem to be assuming that the shield's shape must be roughly spherical with the ship in the center? Most settings that I can think of that uses shields are usually flexible with the shapes they can generate, and it would make sense for the ship to be at the bottom of the bubble for landings.

Amusingly, the idea you seem to dislike was in the original version of episode 4. Luke's X-34 had a shield bubble under, but this effect was removed in later releases.

Guardian said...

The ship doesn't need to be in the center, just within it. I always imagined it at the bottom of the shield, as on take-off… I am not sure how that didn't translate.

I still don't know what idea it is I supposedly dislike, either, nor do I know what an X-34 is. Do you mean the T-16, slayer of womp-rats?

(Googles)… ah, I presume the EU gave Luke's landspeeder a designation. Bleh. Anyway, that wasn't a shield, just a visible repulsor cushion. It's gone now anyway.

Lucky said...

1) If you are picturing the ship at the bottom on take off and landing then what would be the problem? If the shield is basically hull hugging then there isn't a problem.

2) There's no need to bite my head off. X-34 Landspeeder is the designation given at starwars.com for the speeder model Luke sold in episode 4.

Guardian said...

I am not biting, we just can't communicate. The problem with landing is fritzing the shields on ground touchdown. Does it help you if I point out that I have at no point expressed a concern with the ship falling? If that is so, then perhaps you'll understand that is not the problem I was talking about. Implosion of the air is.

As for StarWars.com, the new Disney canon has nullified its use as a source of nomenclature for me. They're accepting all kinds of crap names now.