You’ll find that nuclear fission is not very different.

Nuclear submarines for example only need to be refueled once or twice in their multiple decade lifespan.

Not all, but a lot of this equipment is also made by caterpillar, right?

Well I have no experience with these particular drives, but they do seem to have 11 platters. Which is beyond insane as far as I’m concerned. More platters means more moving parts, more friction more noise (all other things being equal).

It does, it produces low and intermediate level waste, the waste decays over about a hundred years, not thousands. So it’s better, but still an issue requiring management.

I think people still don’t understand what the problem is with fusion. The problem is not that it doesn’t work, it will work, and soon. The problem is that everyone seems to think fusion means cheap limitless energy, and that couldn’t be further from the truth. When fusion does finally work, it will be the most expensive form of energy available. That’s going to be a gamebreaker, right out of the gate.

So far, the only method we know of to guarantee that your reactor will be energy positive is to make it truly enormous. Let me tell you, going truly enormous is not a good way to keep costs down. But let’s say you just spent 8 years building a cutting edge fusion power plant and you want it to work smoothly. Well you better hire a large team of nuclear physics PHDs to keep that reactor working, they must be a dime a dozen, right? You’ll need them for all the maintenance of your cutting edge reactor, get ready for those maintenance costs to mount up. And be prepared to continue paying for all your staff and facilities even while the reactor is (frequently) power down for maintenance.

Also, you do have an economical way to dispose of nuclear waste right? Because fusion reactors are probably going to generate a significant amount of nuclear waste… That’s one of the side effects of actually turning the high energy particles released by the reactor into heat. Those free protons and neutrons get absorbed by a physical shield around the reactor called the blanket. That blanket becomes radioactive over time and needs to be replaced. Congratulations, your clean fusion energy is now producing radioactive waste, and your back to the exact same problems we have with fission.

My advice, keep using the nuclear energy we understand really well at this point, fission. Also, renewables and storage are already a cheaper solution to do exactly the same thing fusion will eventually do. I’m certain that fusion will be a fantastic technology for large spacecraft someday, but I make no promises it will ever become the first choice for general terrestrial power generation.

That turns out to not be true, at least not with the tokamak reactors most groups are pursuing.

You see, at some point you need a shield around the reactor to actually absorb all the high energy particles released, and turn that energy into heat. That’s the whole point of the reactor, to generate heat and run a turbine. You absorb those high energy particles with a “blanket”, that’s just what they call the shield around the reactor.

Here’s the issue, absorbing all those high energy particles necessarily results in transmuting the material absorbing them. That blanket becomes brittle and eventually needs to be replaced. Not coincidentally, that blanket is also now radioactive, because you’ve bombarded it with protons and neutrons and it’s now partially made up of unstable, radioactive elements.

So while fission reactors have radioactive fuel rods to dispose of, fusion reactors will have radioactive blankets to dispose of. Who knows if this is an improvement.

Have you used other ebook readers?

My mother in law had a nook, and that was one of the worst goddamned devices i’d ever used. Low res screen and cheap buttons, buttons that you had to use all the time because the touch controls were so awful. The interface was just extraordinarily bad.

I hate to say it, but the Kindle line are the best devices on the market for ebooks. But I’d pay a little extra if Besos got kicked in the balls with every purchase.

Also note that 100km is the minimum height to be “in space”, not the minimum height for achieving orbit.

That doesn’t really mean anything. You could achieve an orbit at a lower altitude if you wanted to, it would decay faster, but you could do it. The 100km karman line is an arbitrary thing, there is no solid line where on one side you can orbit and on the other side you can’t.

Finally, I disagree with the note that having “enough fuel” to reach orbit means they have demonstrated such capability

Well this seems like a bad semantic argument to me. I guess the question is, what does it mean to you to “demonstrate capability”. Like, for you, what would be the difference between demonstrating a capability to do something and actually doing that thing? How would those two things look different? Or in this specific case, how could they have demonstrated that capability without putting their rocket into a stable orbit (because it would be negligent to do that with this prototype rocket)?

Given what they have done, is there any reason to doubt they could have gone a little bit further? And conversely, was there a good reason to stop where they were, or do you think they would have gone further if they could have?

Well I love talking about space, thanks for reading all that ;-)

As far as I understood it, SpaceX uses the word “orbit” liberally.

No, that’s not really right at all. With this last flight they brought the starship above 200km (100km is generally considered the point at which you’re in space), so they definitely went much higher than they needed. In low earth orbit, the velocity needed to hold that orbit is about 28000 KM/H, they kept their velocity below 27000 KM/H for safety/responsibility reasons. That way, if something failed and they couldn’t relight their engines, it would naturally come down anyway in a predictable manner. The closer you get to actual orbital speeds, the less predictable the re-entry and impact location will be, so 27000 KM/H is really as high as you want to go if you want to ensure predictable re-entry. It looks like they maxed out at 26750 kmh.

Also, after they reached 95% of orbital speeds, we know they still had lots of fuel in the tank because it had enough to slow down and land exactly where they wanted it to. And then… it still had enough to explode in a huge fireball, so clearly the rocket could have gone further. Or to look at it differently, all the propellant mass that got used up in that huge explosion at the end, that could have been payload mass. So clearly it has the capacity to put up a payload as well. I think the reason they haven’t yet is that mastering the reusability aspects are just a higher priority than the payload bays, I think we all trust they can design a payload bay when it comes time for that.

Doesn’t the existence of this modded truck prove that statement wrong? Because I’m pretty sure you made the only statement explicitly refuted by the existence of this truck.

Congratulations?

Um, no?

The rocket has been to orbit twice now, they’ve already demonstrated that. They’re working on the bonus mission, landing everything and perfecting the hardware to the point where it doesn’t need major refurbishment between flights.

Yeah, it certainly could have been better. I believe the original plans were for both the booster and orbiter to essentially be planes able to land on a runway. It’s really a pretty awesome design, I mean can you imagine if we had a fully reusable launch vehicle in the 90s?

But the truth is, the shuttle was never really reusable, it was more like… refurbishable. It took a lot of maintenance for the heat shield and the engines after every launch. It was also amazingly complex, there were so many possible failure states, and in many of those scenarios there was just no hope for the crew. With a shuttle and with the future starship, we’ll be seriously missing the launch escape system seen in traditional crew capsules. On some level, the last thing I would want would be to lose a whole shuttle crew and two booster pilots. (Though admittedly, these days the booster would certainly be unscrewed). I do also wonder, how much potential payload mass they’d lose by adding all the additional parts they would need to make the booster a landable aircraft.

Anyway, it is possible NASA could do that again, but it would be a serious investment to get that working, and right now I think they just aren’t set up to take on a project of that complexity. Also, it would definitely distract and redirect funds from their ongoing science missions.

So yeah, they could, it would be cool, but I don’t think it’s a good idea.

Indeed, NASA stopped launching rockets with the space shuttle. But that was the single best decision that NASA ever made. The space shuttle was an extremely expensive death trap. (It was damn cool, but a terrible way to get to space)

It sounds concerning to put all the egg into the basket of private enterprises.

You can blame the trump administration for that, with their commercial cargo and commercial crew programs. But the truth is, NASA has always heavily relied upon private companies, it’s just that in the past they were all defense contractors (Boeing, Northrop, lockheed, rocketdyne, ULA). The other annoying truth, these commercial programs have actually been wildly successful (except in the case of Boeing’s participation).

But it’s been wildly successful in a few respects, one of which is that nasa has been able to focus on exploration again. Without having to support the huge costs of the shuttle program, they’ve been able to put a lot of their money into landers, interplanetary probes and space telescopes. I think we have more ongoing exploration missions than ever before. The Europa clipper mission launched just yesterday (on a SpaceX Rocket coincidentally). https://science.nasa.gov/mission/europa-clipper/

All good.

And yeah for the record, I do think Bitcoin is pretty brilliant and that Etherium has some real unique utility. I think there are definitely some others that are genuine attempts to do something useful, but few that have really achieved much so far.

I make the point that what cannot happen?

I’m sorry, I just didn’t quite understand what you mean.

Haha, I’ll give you 100 CocoCoins if you can define what makes a cryptocurrency “fake” rather than real.

This headline should probably say “FBI create a cryptocurrency to expose…”

That said there are only a few cryptocurrencies I would call worthy of note or respect.

We can’t afford to use SLS. If you want to use SLS for all of the missions we have slated for starship, you’ll need to multiply NASA’s budget by 2 or 3.

Honestly, I’m not worried about starship reaching its goals, it’s moving along. They’re attempting their next major launch tomorrow morning, the first launch to include returning the booster and catching it with the tower.

take the Artemis contract away from this idiot and SpaceX

What? And give it to who? Besos? Boeing? China?

I guess the only workable option would be to have the ESA do every Artemis launch. That could work, but it’ll likely cost 10 times more and take another 20 years.

Also, the primary ways they save money is through reusable rockets and building everything in house. As far as I know, SpaceX isn’t skirting regulation more than any other launch provider. That said, I wouldn’t be surprised if they have a higher number of regulatory breaches than other providers, after all, they have a much higher number of launches than other providers.

Don’t get me wrong Elon is a complete asshole, an addict, and at this point a detriment to society. But SpaceX is probably doing the most important work on the planet right now. Fully reusable rockets could usher in a whole new era of humanity. This could easily be just as transformative as the automobile.

I mean, the speaker part makes sense. The vacuum has a speaker so it can make an alert sound of something’s wrong. The most common ones I hear are “please charge Roomba” and “error, please move Roomba” (that’ll happen if it rolls over a grate or something and the wheel gets stuck).

But a cheap speaker is a pretty sensible feature.