Mastodawn

John Shirley Jul 28, 2023

from Wikipedia article about David "I saw the aliens" Grusch

Australian political commentator Caitlin Johnstone pointed out that this resurgence of UFO/UAP coverage is coincident with a renewed U.S. emphasis on weaponizing space: "Is it a coincidence that this new UFO narrative began its rollout in 2017, around the same time as the rollout of the Space Force? Are we being manipulated at mass scale about aliens and UFOs to help grease the wheels for the movement of war machinery into space?"

John Shirley Jul 28, 2023

Johnstone's speculation is not far fetched. There is a history of military intel using UFO claims and hysteria to smokescreen foreign intel regarding our stealth planes, and other experiments and efforts. That could apply to the weaponization of space. These theoretical weapons would be pointed downward, at human targets--not outwards, at approaching flying saucers.

John Shirley Jul 28, 2023

For my own speculation on the militarization of space, see my technothriller novel, which just came out:

https://bookshop.org/p/books/suborbital-7/18871631?ean=9781803363820

Seán Fenian Jul 28, 2023

@JohnShirley2023 👍👍 just bought a copy.

Seán Fenian Jul 31, 2023

@JohnShirley2023 It's very good as a Clancyesque technothriller ... but I find myself compelled to note that it contains some pretty significant orbital mechanics errors. S-7 can't be "geosync over Canada" at 2000km. Geosync doesn't work that way. They're 33,000km too low to be geosync over anywhere.

John Shirley Jul 31, 2023

@zakalwe you're right--although! Although geosync has become a bendier term than that, it has come to mean, geostationary relative to a place on the ground. Maybe I should have said geostationary.

@zakalwe would be be Legrange point?

Seán Fenian Jul 31, 2023

@JohnShirley2023 That's even further out. L1 and L2, the closest two Lagrange points, are about 1.5 million km out towards and away from the sun respectively. They're stationary relative to Earth and Sol, but not relative to any particular point on Earth's surface.
The only way to be holding position 2000km up over Canada (or anywhere else) would be to continuously burn fuel for station-keeping. Not really feasible with chemical propulsion.

Of course, all this said, I'm not holding Sub Orbital 7 to strict scientific rigor because it would need such an insane specific impulse to make SSTO with that mass ratio in the first place. 😉

John Shirley Jul 31, 2023

@zakalwe station keeping in microgravity is not so expensive, necessarily. Or are you saying it's too low for that? At any rate I establish they have new fuels that are highly compressed.

Seán Fenian Jul 31, 2023

@JohnShirley2023 yeah, the handwave of super-densified cryogenic slush fuels is a good one. It helps with the storage volume at least, which cuts down on structure required to hold fuel, and hence overall mass.

The thing about 'station-keeping in microgravity' is, relative to what. Relative to the ISS? Easy. Maybe a half-second burn every couple of days just to correct for drift. Relative to the Japanese station (which I haven't actually gotten to yet)? Again, easy. Really, drift is all you have to worry about.

But holding station above a point on the ground is a whole different problem, because in a 2000km orbit you're moving about ... lemme see ... roughly five kilometers a second faster than the ground is.

Honestly? Thinking about it if I were going to fix that, I'd forget about geosync and just change that "geosync over Canada" to something like "passing over Western Canada right now." That avoids all of the major orbital-dynamics issues, and everything else is handwavable.

John Shirley Jul 31, 2023

@zakalwe Frequent steadying adjustments, carried out automatically, is not inconceivable...if I get a chance to do a re-edit I'll throw that in. What about ion thrusters? Is the ship too massy to be helped by them?

Seán Fenian Jul 31, 2023

@JohnShirley2023 Not CURRENT ion thrusters, but maybe future ones. They're really the wrong tool for the job, even for orbital station-keeping.

There's actually one type of very clever thruster that uses no fuel at all, but again it's very low acceleration. Fundamentally you spool out a very long wire, charge the wire electrically, and use the reaction against the Earth's magnetic field to generate thrust on the order of .001G.

John Shirley Jul 31, 2023

@zakalwe right I read about that! Thanks for the reminder, if I write a sequel I'll work that in. It's very cool.

Hey do you think space elevators are plausible?

Seán Fenian Jul 31, 2023

@JohnShirley2023 Totally, given the right materials. And we're working on developing materials with sufficient tensile strength.

Skyhooks are a similar idea that in certain respects are actually easier (in theory) to build.

John Shirley Jul 31, 2023

@zakalwe I am trying to make plausible an idea that an overheated Earth could somehow draw heat through space elevators and skyhooks (along with their original purpose) to cool off especially threatened areas of the planet, the heat then used to generate energy at the orbital end of the elevator etc. Ridiculous? Possible?

Seán Fenian Jul 31, 2023

@JohnShirley2023 Hmmmmmmmm.

If the supermaterial used to construct the elevator were also a thermal superconductor (which is not implausible; diamond conducts heat so fast it is close to being a thermal superconductor), I have no doubt you could power an orbital facility using heat carried up the cable.

The amount of heat you'd have to dissipate to significantly cool areas of the planet that way, though, is staggering. Look on the web for David Morgan-Mar's Irregular Webcomic. In one of his footnotes he discusses in detail the hypothetical thermal dynamics of keeping Coruscant from cooking itself. (Or trying, at any rate.) It explains the problem well.

Realistically, I suspect that any future approach to actively cooling the planet is going to have to rely on preventing some of the incoming solar energy from reaching the planet in the first place. We've demonstrated that it is technically possible to beam infrared lasers into space, but lasers are so inefficient that it's a net loss.

John Shirley Jul 31, 2023

@zakalwe Yes I've thought about the challenge of getting enough heat up. It would be a local effect, but one that could affect meteorological conditions, I hope positively, perhaps creating a greater likelihood of rain, condensation...you'd have to have a LOT of these to make a difference. If it helped ten percent it might be worth doing if you're making space elevators anyway...The Earth might end up looking spiny...could provide energy to be translated into electricity for orbital use...

Seán Fenian Jul 31, 2023

@JohnShirley2023 Yeah, if you're already building the elevators and the materials HAPPEN by narrative chance to have the right properties ... sure, if you've got it there already, why not use it? Every little helps. We only need a few percent.

You could possibly even deploy solar-cell "parasols" from the geostationary point on the elevator and transmit the power back down the cable, if it was an electrical superconductor as well as thermal.

John Shirley Jul 31, 2023

@zakalwe right! That could serve dual purposes, create coolant areas (and possibly rain where there wouldn't have been?) I mean, heat rises...so if you could help it rise...and rise and rise...

John Shirley Jul 31, 2023

@zakalwe re the SSTO in S7 - You're saying the orbital vehicle's mass ratio wouldn't work out? But of course this is set in the future and assumes new technologies...and some of it based on some material leaked to me by...er, friends in classified places...but it's thought to be plausible. First of all it hasn't got the mass of something like that attempted now--new lighter yet powerful metals are coming (and marvels like transparent metals). Yeah I thought LaGrange wouldn't work.

Seán Fenian Jul 31, 2023

@JohnShirley2023 I think the mass ratio can be handwaved with your superdense-fuels gambit. Lighter materials, denser fuel storage, more efficient engines...