Well, off the top of my head, the main issues are going to be the sleds, the rails and how much they allow to reduce the mass of the plane itself.
Accelerating the sled with something other than the vehicle's main engines makes the most sense. Otherwise you've just overcomplicated a runway and end up back in the pit of spaceplane-style SSTOs. So assuming they're gonna boost the sled, how? I don't think liquid engines have the yeet to get up to a worthwhile speed on the rather short rail. Solid boosters? They have yeet, but once you've lit them, you can't really turn them off and that leaves you with woefully few abort options between ignition and launch. Electromagnetic? Getting enough yeet is a matter of enough (and big enough) capacitors, but the rail erosion is going to be worse from the sheer waste heat. And any attempt at recovery of the sleds will require the rails to be extended to decelerate them. Cause you'll want to get the vehicle going as fast as possible, within the limits of what the structure and payload (alive or inert) can handle. But once you've done that, you're not gonna hard stop the sled and reasonably expect to recover anything but twisted metal and composites.
The other question is how much is it gonna help in reducing the vehicle's mass? The friction from doing even Mach 1 near sea level means the vehicle has to be reinforced to handle it, maybe even require active cooling of the hull. So that's going to cut into whatever extra payload mass they'd get from the launch speed. And the vehicle's engines will still need to work damn hard to climb up the well, in which case low Mach numbers aren't going to do much and might actually be counterproductive thanks to the high drag.
My most insane, pie in the sky, they'll-never-try-this idea? The rail is angled up a mountainside at about a 45 degree angle. Electromagnetically accelerated, it's basically a huge Gauss cannon and the sled yeets off with a 4g acceleration. By the time it reaches the end, it's going at about Mach 1.5, at an altitude of 2-3km, at which point the vehicle lights its engines and disconnects from the sled (Spinlaunch has shown that fraction of a second precise release is possible). The plane continues to ascend, the sled just fucking runs off the rail and coasts to peak altitude, then deploys parachutes to descend back to the ground. But this is an entirely unreasonable idea. Construction and maintenance would be ludicrously complicated and harried by environmental concerns. The energy required would probably be comparable to that of a small town. There's way too much risk of the sled colliding with the plane at the end of the rail, not to mention the parachute descent. On the other hand, goddamn, it would be awesome!
The skepticism is reasonable. The theoretical principles are sound and there's a lot of math (done by actual scientists and engineers, as well as sci-fi writers) to show that, in some form, it would work. But this is a huge undertaking that's never really been tried before, so no one really knows how difficult (and expensive) building and operating it is going to be. Honestly, I expect this to fall apart before they begin high altitude suborbital tests of the rail launch system. On the other hand, it's such wonderful sci-fi shit that I can't help but root for them. If they can secure the funding to continue developing this, it's gonna be fascinating!
The rail launch is going to be interesting. Presumably, the sled is separately accelerated, to give the vehicle a little kick and save propellant. It won't be much, even a 4g acceleration would only get it up to roughly Mach 1.5 before it runs out of rail, but it's not nothing either. And unless the sleds are single-use, they'll need to decelerate them somehow.
But man, bring it on! The premise of initially accelerating a vehicle on a rail or launch loop, before the vehicle's own engines kick in, is probably the closest we can get to SSTO from Earth. At least without using nuclear propulsion.
No. The pulse still took longer than light through vacuum. That's the limit that needs to be broken for any causality violations to happen and that's the limit that can't be broken.
Right now, the Earth is losing mass at about 55 000 tons per year. Yes, losing. About 100 000 tons of hydrogen and helium escapes the upper atmosphere, partially offset by roughly 45 000 tons of dust and meteorites getting scooped up along our orbit.
Considering this has been happening for millions of years, I think we're quite safe from affecting the Earth's mass and orbit within the span of even centuries.
But it's much more likely that the majority of material mined and processed in space will not be coming down to Earth. It's much better put to use in orbital construction, or shallower gravity wells like the Moon and Mars.
You're entirely right that getting to the rocks, and getting the mined stuff to where it's actually useful, are gonna be a problem. Maybe we'll finally get some nuclear thermal engines, cause the shite ISP of chemical rockets is really insufficient for these trips and ain't no one wanna wait on the gravity assists.
Fingers crossed this woman doesn't end up with a Zydrate addiction. It comes in a little glass vial, you know.
NASA has the measurements of all their astronauts and Dragon flight suits for Butch and Suni are already made.
It's stronger than aluminium, as well as easier to manufacture and work in less-than-ideal conditions than carbon fiber. Useful traits when your end goal is to build a whole fuckton of the biggest, most capable, fully reusable rockets in history.
Crew Dragon has been solely responsible for the US side of ISS rotations for four years, without incident. 8 successful missions, not counting the privately funded trips. Cargo Dragon has been doing resupply missions since 2012.
Yep. And if they fail to deliver on the lofty expectations they've created here, the backlash is going to be epic. I don't want to root for their downfall, but.... Imma stock up on popcorn.
A lot of that time, if not the vast majority, is likely performance testing. That's trivial to automate and can be run across 100+ systems simultaneously.
Because now it's practically a necessity. Before that, you could easily not put a case on your phone, exercise some basic care with it and you would've been fine. None of my previous phones had a case on them. Not a one. Because I don't drop them, I don't throw them and I don't use them for hammering in bolts or whatever. But the camera bump finally got me to put a case on my phone, because the damn thing not sitting flat on a flat surface annoyed me too much.
The show made a fair few changes from the books, mostly for the better. Off the top of my head, Avasarala and Draper are introduced earlier in the show, Drummer got the consolidated stories of several other side characters and Elvi Okoye's and Ashford's personalities were significantly changed. IMO, Show Ashford is a much more interesting character than Book Ashford. In addition, the season 6 side plot with the kids is told much later in the books.
Admittedly, I'm not up to date on how the preparation is going, but a Space News article from last month claims they're still looking good for the launch window. Blue may have hoped that ESCAPADE wouldn't be the very first launch, but that ship has sailed. Wouldn't count them out just yet, not until some critical failure lifts its ugly head. But for my money, the most likely, and most disappointing, outcome is that they scrub due to technical problems and end up missing the window. First launches rarely go off without a hitch. Still gonna be rooting for them and watching whatever stream is available.
I'm glad to see Blue starting to aim high, but all of this is heavily dependent on New Glenn's first flight going well. Fingers crossed, there's no major problems with the rocket and they can remain on track for this mission.
Thunderfoot's psychotic obsession with Musk and the complete denial of reality happening before his eyes it necessitates has destroyed any credibility as a scientist he ever had. The authority of a food chemist on matters of rocket science is questionable in the first place. Your blind, unquestioning acceptance of whatever drivel escapes his frothing mouth is no less pathetic.
And with that, I'm going to toast to the memory of the brain cells I've lost over the course of this "conversation". Hoping for anything even resembling a reasoned argument from you is clearly a fool's errand.
Fucking lol.
EDIT: Hoo boy, you didn't even look at what you linked, did you? My point was that SpaceX has completed 8 crewed missions. The video is just half an hour of Thunderfoot's inane rambling about launch costs. Not a single word about whether or not SpaceX has completed any crewed missions, ISS or otherwise. That's the point I'm challenging you to disprove here. Go ahead. Show your work. I'm looking forward to it.
They have 8 incident-free crew missions under their belt. Sit your ass down, the adults are talking.
What's your reasoning behind the claim that a company that's been transporting crew to and from the ISS for 4 years, and currently has a vehicle docked to the station, is incapable of launching a tenth mission? Mind that said mission was supposed to launch next week, but Starliner is being a pad princess in orbit and won't get off the required docking port.