Sci-fi Weapons, Vehicles and Equipment

Nothing could possibly go wrong with that plan!

Honestly the biggest issue is not blocking the sun, but Kessler syndrome

Nitpick here but a desert is defined by its precipitation and geology, not how much Sun or heat it gets. The Antarctic is by and large the world's largest desert, despite having an average thickness of about 1000 meters of ice. (It rarely snows there in any real quantity, what falls stays there.) The geological definition is because you can have sufficient rainfall to be something else but the geology prevents any biological features from forming. An example of a geological desert is a fresh lava flow or a salt pan or the top of a mountain above treeline.

True deserts are gauged by the precipitation definition but geological deserts are used for purposes of mapmaking, navigation and biological study.

edited 24th Sep '16 2:06:21 PM by MajorTom

Tom: Part of what helps reduce that precipitation would the large amount of heat in the hot deserts that the desert floor absorbs often pushing weather systems out of the ideal rain zones via thermals you get a very similar effect with cities altering weather patterns because of their thermal foot print from the sun alone. It also dries up any fallen rain or standing rain preventing any hard ground soil from ever softening and being able to host more plants and nutrients. Damp soil holds down against a wind a lot better then significantly drier soils to boot.

Not necessarily. As mentioned, the Antarctic is a desert. Beyond that, most deserts on this planet occur because of three reasons: Lack of oceanic convection leading to a weaker water cycle (as happens in the Arabian Peninsula), cold water currents that stabilize the upper atmosphere and most importantly rain shadow effects caused by terrain which account for over 90% of the world's deserts.

You could drop the temperature of the Sahara desert permanently 20 degrees Celsius right now and it would still be a desert little if any changed from what it is now especially in the north. It is precisely because of the reasons mentioned. The Atlas Mountains in northwestern Africa cause rain shadow effects for everything coming from the north and west. (This is combined with the European Alps.) And then it gets the double whammy of from oceanic effects, specifically a lack of convection in the Mediterranean compared to the North Atlantic Gyre. Oh and it gets worse, the Canary Current works as a stabilization agent for the west coast of the Sahara. The deep upwelling of cold water caused by that creates atmospheric stabilization. It kills storms. (Same thing current-wise happens in California, Peru, western Australia and Angola which is why they are a lot drier than similar locations at their latitude.)

The geological record is rife with this. Many present day deserts were still deserts in the last glacial period when the planet's climate was a lot cooler. This includes the Mojave, the Sahara, Sonora, Atacama, Gobi, Great Australian Sandbox, and Antarctica. Some of those deserts such as the Sahara were smaller on account of some of their fringes having increased precipitation because of the nature of the glacial period climate. Other parts were underwater because while the precipitation didn't change, the lowered temperature did lead to reduced evaporation. This is why the Bonneville and Great Salt Lake Deserts, the Great Basin of Nevada and numerous other areas exist largely as salt flats. Water would flow in from elsewhere but the temp wasn't high enough to evaporate it all away.

So what you're saying is we could use atomics on the mountain ranges a la Dune to terraform the deserts of Africa?

Literally leveling the Atlas mountain system would effect a change in the climate of north Africa. It would lead to increased precipitation across nearly the entire region. How much is an open question though owing to the Canary Current.

Most likely the northern reaches of the Sahara would become more akin to the drier portions of Italy and Spain.

Curiously, I think you might get a much more drastic change in climate of a desert if you used the Atacama and leveled the freaking Andes Mountains.

For Science!

edited 24th Sep '16 6:07:37 PM by AFP

So, if you guys wanted to make the most plausible (or hell we can go soft here if we want to get creative) reason for the Space Is Air trope and fighters working exactly, or almost exactly as they would in atmosphere, what's your most creative explanation/idea?

The best I have is gravity generators for my use of fighters.

In the Wing Commander franchise, ships and fighters use magnetic scoops to collect free hydrogen in space to keep their fusion reactors topped off. The result is that they can use the scoops like airfoils to maneuver. If they close the scoops, they accelerate rapidly but can't maneuver hardly at all.

Mind, even that assumes quite a bit of hydrogen gas just floating around in space.

edited 25th Sep '16 6:13:39 AM by AFP

There is one semi-plausible reason: Fuel.

To do the most extreme maneuvers in space requires a lot fuel. Sure in astrodynamics there is nothing to stop you from literally spinning 180 degrees in place, firing the thrusters and going from there. But that requires a lot of fuel to fully decelerate from your original vector and then accelerate to any kind of speed going in the new one.

A banking or more traditional turn while a lot longer requires a lot less fuel since you wouldn't need to do a traditional long duration burn to decelerate and re-accelerate.

In a setting where fuel is a lot less concern such as if you were powered by Impulse drives, Repulsor Drives, fusion engines, EM Drives or whatever form of Reactionless Drive or whatnot you can think of this can still can apply. Maybe your stuff can't put out enough power to fully do such maneuvers efficiently in combat thus leaving you very vulnerable attempting such stuff. Maybe your spacecraft was built with the trope in mind and is not able to handle the stresses of extreme maneuvers like that.

Whatever the reason, it's somewhat easy to justify Space Is Air.

Actually I'm pretty sure banking maneuvers and the like would use more fuel. If the goal is to change vectors from Vector A to Vector B, there is a certain minimum amount of energy you will have to spend to get there. If you go there directly, it'll be faster than taking a long leisurely curve.

The only reason the banking turn is more efficient in an atmosphere is because you're in an atmosphere, which is pushing against you the whole way. Your aircraft (or seacraft) is designed to utilize the medium to provide lift, and to manipulate it by inducing drag to swing your craft around in different directions. Trying to make the turn directly would be more expensive because the air is still moving all around you, and any hard sudden turns would have to work against said medium, while also potentially losing you that lift you were generating by moving through it in a straight line.

Gravity Generators. Make it so the craft in question pushes gravity on either side of the craft to mimic atmospheric effects.

That's how ID: Resurgence explains it.

That's how it works in my setting with fighters.

"Big rear-facing thruster for acceleration, space warping gravity thingamajigs for maneuvering" tends to be my go-to handwave for that trope too. Especially in Star Wars, where I basically just shrug and say "They've had hyperdrives longer than we've had the wheel. If they want their space ships to fly like WW2 era fighter planes for some reason, they probably can.

Had a rough idea for a kind of space-sim game. It was mostly set in a huge cloud of gases and dust in space, held together by a membrane of technobabble, with large areas of similar air pressure. I don't think craft would have handled quite like planes, though; There's friction, but no gravity... A typical one might have the main part in the middle, with four arms projecting out of it with 90 degrees between them, each with propellers, and able to change their directions to steer.

edited 25th Sep '16 12:09:03 PM by ManInGray

Not necessarily. Orbital slingshots are basically long banking turns and they'll get you anywhere and any direction a lot faster and more efficiently than simply turning on the spot and hitting the gas.

Tom: Apples and oranges to a hot desert and you know it. The arctic already has extensive amounts of moisture present on the ground except it is frozen. The arctic's problem isn't a lack of present moisture it is that any that arrives is turned to ice.

Yes the amount of heat a desert floor absorbs everyday is a key factor in both weather patterns and water retention in hot deserts the world over. That isn't exactly a new revelation. A 20 degree drop of temperature would also quite likely drastically alter regional weather patterns especially around a large desert like the Sahara. Again that thermal effect plays a huge role in altering beneficial weather patterns in a desert. Rain shadows from mountains are only limited to regions immediately around mountains. There are more then a few deserts not anywhere near a mountain range. The thermal pattern has long been known to drastically alter weather patterns. Any piece of terrain that can absorb and reflect large amounts of heat have a well documented and studied effect on altering weather patterns. It is a huge part of why large cities cause desertification and alteration of previously known or recorded weather patterns in the past.

You are also aware that during the ice age places like the Mojave were well known as playing host to a signficantly more water and wild life then is present now right? Case and point.

I mean it isn't like a museum with trained experts knows any better or anything like that. Both the Geological and fossil record disagree with you by huge degrees there Tom. Even the Sahara used to be pretty wet and green at one point. See here

So no your assertion that deserts were always deserts is frankly inaccurate and 5 seconds on google could have helped you with that.

edited 25th Sep '16 12:24:24 PM by TuefelHundenIV

This only works in a specific situation though (that is, when there's a gravitational field to exploit). It's not necessarily faster either. And it's barely superficially similar to a banking turn.

As a general rule, it's more efficient to just thrust in the direction you need rather than do a nice curve.

Actually, "banking" doesn't make any sense. In a zero-friction environment, to change direction you simply cancel your forward momentum, and apply sufficient delta-v to accelerate toward the desired direction at whatever velocity you want. If you are moving 10 m/s in direction A, then you have to cancel that forward motion and accelerate in the new direction. Any additional maneuvering you do, banking turns or whatnot, just wastes fuel.

Besides, a slingshot maneuver isn't even really a banking turn, it's just falling with style.

If you're applying acceleration over a length of time you'll produce a very bank-like course but you're not really banking.

Literally it should be called "curving". And it's not something that anyone would do deliberately, but only as an outcome of the different vectors acting on the spacecraft (at least I cant think of any reason to do it).

And scaled out from far enough away the curve will look like an angle.

On an unrelated note, what are some semi-plausible man portable power sources could I use to power an exoskeleton?