isaackuo

isaackuo, 11 hours ago

@tkinias @nyrath @cjshearwood

Do you mean, other than the obvious that glass is heavier and more delicate, so you do NOT want to have too much of it?

Also, there's the public relations factor - passengers want to fly in an aircraft that "feels" safe. And having too much glass in the front "feels" unsafe.

Also, multi-engine aircraft cockpits were (and remain) absolutely stuffed with instrument displays and controls - both below and above the windows.

isaackuo, 1 day ago

@Benhm3 @nyrath

The basic idea behind a gravity tug is that it will NOT result in bits of the asteroid breaking off (which, in certain circumstances, could be a problem).

But it seems that lots of asteroids are rubble piles, and it could be worth doing the opposite approach. An anti-mining probe could just dig/melt in and then flail a chain tail around to randomly knock regolith away. Low velocity is good - maximizes thrust for power.

isaackuo, 1 day ago

@nyrath

A counterintuitive aspect of using the asteroid mass itself as propellant is that you want a LOW exhaust velocity. Not only does this maximize thrust for a given amount of power, it also conveniently gets rid of asteroid mass - so it takes even less energy to deflect what's left of the asteroid.

But for this, you'd rather not waste energy on vaporizing the rock. That's a lot of energy that basically gets you nowhere.

The secret is to bang the rocks together.

isaackuo, 23 hours ago

@glitzersachen @nyrath

Well, I was just quoting The Hitchiker's Guide to the Galaxy "The secret is to bang the rocks together"

But anyways, any of the concepts for deflecting an asteroid could be used to deflect a small asteroid into a large asteroid - given a lucky enough circumstance of the small asteroid already being sufficiently headed toward the large one. Gravity tractor probably wouldn't work on small ones, though.

isaackuo, 8 days ago

@nyquildotorg

I don't have any idea, but your statement sounds plausible.

isaackuo, 11 days ago

@Hcobb @nyrath

If you've got plenty of power - and a Dyson swarm does have plenty of power, then a laser sail at the destination can decelerate you just as well as accelerate you. (Actually better, due to both the doppler effect and the chasing effects working in your favor.)

isaackuo, 11 days ago

@Hcobb @nyrath

It's going to depend on specifics of the overall system, but 1 gee of acceleration is possible. Two possible strategies is to have extremely high reflectivity with a visible or soft UV laser, or to have a sail material tolerant of high temperature (and this allows the use of X-ray or even gamma ray lasers - but this is not required).

With high reflectivity sails, you may need to be careful about doppler effects and the angle of incidence.

isaackuo, 15 days ago

So, LH2 tank engineering is not trivial. If you want it to launch from Earth, then you have to confront icing and insulation. For various reasons, this works best with a single layer of structural tank, with insulation foam applied outside that and optional paint outside that.

But this becomes a problem if you have dreams of using these big LH2 tanks for a space habitat. Bits of foam breaking off becomes space debris - a hazard in LEO.

1/2 #PostcardsFromCutty

isaackuo, 15 days ago

Thus, Essex was not allowed to operate in LEO, severely limiting its ability to bring in revenue. Besides, its avionics and various systems degraded and became obsolete, so Essex was scrapped.

Cutty's ship would be built around its LH2 tank, repurposed into a crew compartment. Spraying the outside with large cellulose bubbles both solved the problem of space debris and provided Whipple shield-like impact protection.

2/2 #PostcardsFromCutty

isaackuo, 16 days ago

@Hcobb @nyrath

The ideal size is not seven. Blakes 7 just couldn't ever get the hang of giving all the characters something to do.

isaackuo, 18 days ago

@nyrath

Page 7 "optional boom" ... Captain Ivanova does not approve.

isaackuo, 22 days ago

@nyrath

I kinda like the idea of taking inspiration from wooden ship days. Back then, it might not be so much a matter of different purpose built logistics ships, but rather a ship's purpose could evolve with age, as it gets worn out.

https://en.wikipedia.org/wiki/Hulk_(ship_type)#Hulks_used_for_storage#Hulks_used_for_storage)

isaackuo, 23 days ago

@KarlSchroeder @nyrath

Martian gravity is .38g, whereas lunar gravity is .17g. So, the floor angle to simulate 1g would be 22 degrees rather than 10 degrees.

So basically, it would work about the same as on the Moon, just with about twice the floor angle (not all that much different in the big scheme of things).

isaackuo, 23 days ago

@maxthyme @nyrath

Worth noting that this was done in space, at zero gee rather than low gee. Skylab had a circular track made of small cabinets.

https://www.youtube.com/watch?v=qiMq-fdRhLo

isaackuo, 28 days ago

@tkinias

I think that fusion research physicists actually have a pretty realistic idea of what the money would likely result in, but they know this won't get them the funding.

So, if this money isn't wasted of fusion research, I expect it would be wasted on some other field which is 2nd best at making duplicitous promises. Maybe solar freakin roadways.

The challenge is to figure out how to design and maintain a system that can disincentivize the B.S.

isaackuo, 28 days ago

@tkinias

I can't say I'm optimistic that it would have led to any sort of fusion power, but it could have encouraged more people to go into physics knowing there was a well funded jobs program for it.

Also, it's possible we might have a spinoff technology to show for it all.

For example, the VASIMR thruster that has been going nowhere for two decades was a spinoff from MCF research.

Maybe we could also have a Z-pinch spinoff thruster and a pulsed laser thruster going nowhere for decades.

isaackuo, 29 days ago

@nyrath

In the meantime Matt Murdoch is running around lasing everyone and everything everywhere like a madman, maniacally laughing.

@Robert_Brandt @Hcobb @eldadoinquieto @peterdrake