4615

You fools! Have you learned nothing?!

4616

Well, to point 1. “They” seems to be “it.” Carbon and water, we kinda have a lot of that. To Point 2: you’re building them on a moon, not in space, and you’re incurring all the insane costs, danger, and inefficiency it brings.

Helium-3, I get. We don’t have it, the moon does. The spreadsheet could work out. Making a thing on the moon out of aluminum or steel and also having a launch pad (which presumably used up all your regular elements) and fuel (which probably doesn’t have the precursors necessary on the Moon to begin with, we’d have to ship them up) and etc. etc. doesn’t seem viable. Moon’s a big ball of compressed dust, right? A worker on the moon is going to cost what, fifty grand an hour, just to throw out a number?

I guess gripping hand, we went to the moon fifty years ago, and didn’t bother to go back. We’re not known for turning out backs on an exploitable resource if the numbers work out.

One argument against my stance would be that we’ve come so far in those fifty years that efficiencies and whatnot make it viable, but the reality is we’re still building aluminum tubes and filling them with LOX and something burnable, just like we did back then. Just like nuclear reactors, coal power plants, etc. etc. are still at the end of the day a friggin’ steam engine.

4617

If we have Helium 3 and Water, fuel could be manufactured on the Moon itself. At least that was were I was getting at.

The Moon probably couldn’t be self sufficient, but you could save a lot of time and resources by manufacturing the needed fuel on the Moon to break the 1/6 gravity that is the Moon, and drop into the gravity well that is the Earth.

Actually, why bother with rockets at all, shouldn’t some sort of Mass Driver be enough to launch something from the Moon to the Earth?

Edit: And of course someone thought of it.
https://space.nss.org/settlement/nasa/spaceresvol2/electromag.html

4618

We need a thread on the real world viability of sci fi concepts.

4619

But anything you build on the moon only needs to be launched from moon gravity, not earth gravity.

4620

That’s right! And if you build it in space, it’s already in space! It’s almost as if there are other considerations than gravity! That we all know about! And really it’s disingenuous to ignore that fact while posting!

4621

Ive been wondering if our satellite/space junk situation has any implications on the viability of a space elevator.

4622

I’m sure the space elevator laser defense system can adequately deal with it by vaporizing all in its path.

4623

Any orbit lower than geostationary will cross the path of the elevator, probably several times twice per day. Relative speed between LEO and the cable would be on the order of 3000 km/s. So yeah, I’d think avoidance would be something to worry about. If the cable is disrupted… well imagine a skyscraper a few hundred miles tall crashing to earth with speed not just due to gravity, but also the tension in the elevator.

4624

…or read KSR’s description of the elevator cable fall and its effects in Red Mars.

4625

That’s totally what I was thinking of :)

4626

We don’t have to buy into it as a general rule of life, but when it comes to launchers, the evidence is pretty clear. Shuttle, according to NASA figures, cost about $450m per launch. NASA’s new SLS - in which they’ve completely given up on reusability - look like costing more than $1billion per launch.

In the meantime, NASA recently paid SpaceX $117m for a Falcon Heavy launch.

4627

Dragging the SLS into this isn’t fair. The SLS is not an exciting space technology program, it’s pure pork for Boeing (and thus to some senators they pay handsomely). The RS-25 engines for the SLS (and previously the space shuttle) were designed in the 1960’s for crying out loud.

If the SLS ever flies (and I’m skeptical), it will be second fiddle to the SpaceX Super Heavy. Possibly third fiddle depending on how well the Chinese do with some of their initiatives.

4628

Offhand, what’s the Blue Origin cost? I think they’ve sent up commercial payloads, yes? Musk went into it specifically to find new efficiencies like reuse of rockets but Bezos so far seems to be in the more traditional mold. Couldn’t google it myself, search results are all inundated with the recent tourism launch.

4629

Those are the reasons why the program is fucked up, sure, but don’t change the fact that this is NASA’s only launcher offering and it’s terrible.

Blue Origin is pretty secretive so hard numbers are hard to find. Also, they’ve only launched a few commercial-ish payloads because they can’t launch real payloads to orbit until New Glen flies (next year, maybe).

4630

Well, I suppose you could argue if they are spending that money then the government doesn’t have to, and any government program would cost much more. So the government can instead spend that money on important social programs, like health insurance for all. Yea, I know, I am kidding. But it should work that way.

4631

I know that reference. except that the elevator fall I remember was from another book and another author, maybe something by Ben Bova?

4632

The space elevator collapses either at the very end of Red Mars, or beginning of Green Mars. The Bogdanovists do this intentionally to break the control by earth corps.

4633

I think I read the final book and a half while a sleep as all the political stuff in it bored the crap out of me. :)

But Bova, I think, has a book where terrorists take down a space elevator?

Okay, in Powersat Bova does has an experimental object that falls to earth leaving a trail “hundreds of miles” long, and it is done by “saboteurs”.

4634

Here is some real liberal stupidity, from Speaker Pelosi:

There may be a good argument against forgiving student debt — that isn’t really the point — but this argument is not it.

“We can’t implement policies and programs that some taxpayers object to” is not an argument you really want to hear from what passes for the progressive party. Every single act of government is vulnerable to that argument. The very idea of society is vulnerable to that argument.