That would be Photonic Induction. His YouTube channel is better than his washing machine video.

Of course it is. And it's a huge bargain because the USPS is operating at enormous losses, losing ~$8B per year.

We don't know because they're not allowed to, unless the letter is "urgent" (overnight or 2-day). I suspect that their prices wouldn't be much higher (if any) than USPS, at least for urban areas. They might even be lower. People who live in more rural areas (like me) would likely pay a bit more, but that seems fair, just part of the cost of rural living.

That's because it's illegal for them to use mailboxes or to deliver first-class residential mail, thanks to the government-guaranteed USPS monopoly on mail delivery.

That might work. While we're at it we should eliminate the monopoly and allow UPS and FedEx to compete with the USPS on all sorts of shipping, and remove all of the remaining subsidies. Let them all compete head to head on price and convenience, on a level playing field.

You can write a Hello, World! program that everyone can read in their own language.

One cat dies for each bit that is settled in the solution.

Hydrogen does not have to be shipped as a liquid or gas (more to the point, it wouldn't persist as a liquid without a significant cooling system). By mass, water is 13% hydrogen, hydrazine is 14% hydrogen, polyethylene is 17% hydrogen, lithium borohydride is 18% hydrogen, ammonia is 22% hydrogen, and methane is 34% hydrogen. Most of those compounds (and others) are useful to have on a ship regardless. And any sort of effective radiation shielding is going to have to be hydrogen rich no matter what; there's nothing that moderates down neutrons to easy-to-capture energies anywhere near as well as hydrogen.

The fun part of it is that the hydrogen enters and leaves the rocket in exactly the same form; it's simply there to function as a working gas for the lithium fluoride.

I'm actually somewhat of a fan of metalized propellants, although that one is certainly extreme. ;) While there's no getting around fluorine's toxicity so I can't really get onboard with that particular propulsion system, I can picture lithium being managed - yes, lithium is dangerous, but so are chemicals like LOX (really, pretty much all oxidizers are extreme fire hazards, if not outright explosion hazards). Aluminum doesn't provide as much of an isp boost as lithium, but it provides a small one, plus a major density boost (and is cheap, too), and is nice and stable. I'm actually working on some experiments for a somewhat hybrid-esque design which involves aluminum structural elements designed to burn away and contribute to the exhaust stream.

Do any of you nay-sayers have a good link to read? I haven't heard that the problem has been solved.

The troll persists because people keep feeding him.

Honestly, I don't know what has to be wrong in a person's life for them to feel the need to spend their time acting like that. But it's the case for some people. I hope that whatever is wrong, things turn around for them.

He's not "asking" anyone to do anything. It's a simple reality that if there was a mission to Mars coming up shortly and you passed a signup sheet around, and at the top of it was written in large letters "YOU WILL ALMOST CERTAINLY DIE AT SOME POINT DURING THIS TRIP", you'd still get thousands of signatures from people who are utterly thrilled at getting the chance and couldn't give a rat's arse about the risk.

I knew there was a reason back in school that my binders all had pictures of sci-fi landscapes on them... it all comes full circle. Mars needs a breading program for colonists to survive... breading requires a binder... binders have pictures of Mars to encourage people to go and support the breading program!

Is that not exactly what the Mars rovers were supposed to be investigating?

No, the rovers have not been gem prospecting. But the data that they've recovered would be useful for doing so. There's a lot of heavy hydrothermal veining near curiosity for example (primarily gypsum, but it's a good start!). What I wouldn't give to be there with a rover with good range...

I've read some papers on the subject, and it really depends on what sort of mineral you're talking about. Mars lacks or is deficient in, as you note, a lot of the processes on Earth that concentrate ores, making certain types of ores deficient. However, there are some types of ore deposits that it's expected to be rich in. A good example is bolide deposits, like the Sudbury deposit on Earth. There a large impactor created a basin which is rich in nickel, copper, and precious metals. It's not that the precious metals came from the impactor - it's that by liquefying a large chunk of the crust, it allows it to separate out into layers. Mars is struck more often by large bolides and the resulting basins are more slowly eroded, so such deposits are predicted to be notably richer on mars.

A problem with mining on Mars however is... well, mining. Overburden problems are likely to be even worse on Mars than on Earth, and I'm sure you've seen what lengths people go through to get rid of overburden. Doing that with equipment light enough to ship to Mars and keep operating? Anything but an easy task. Now, surely there's some deposits in some places that, with good prospecting effort, are low overburden and easy to mine. But then you hit the other problem which is... not everything is found in the same place, and many things distinctly aren't. And furthermore, once you build in a particular place, you're pretty much locked in there. So how do you get everything from point A to point B? Aircraft can work on Mars, but their payload capacities are terrible compared to their size, and you have to make them very fragile. Over a few hundred kilometers, your best bet is probably "mountain roads", aka you plow aside the rocks and dirt as best you can, and accept that you're going to get low throughput/high maintenance hauling over such bad roads. Over longer distances? Honestly, your best bet (in the foreseeable future) is rockets, as expensive as they are. In the long term you can talk durable cross-planet roads, high speed rail, railguns, etc. But those sorts of things aren't practical in the near term - they represent too much embodied mass, power, and/or and labour.

It's not an easy challenge

Site selection is going to be critical. The goal in the near future shouldn't be 100% independence, because that's not realistic. It should be, "what's the highest percentage of this import mass that we can eliminate?" Pick those low-hanging, high-demand fruits first.

I'd think that, considering the risks, a single failure in power and all the frozen embryos will die.

A single failure in power that prevents you from keeping even a small cryopump operating, and you have much bigger problems than keeping (replaceable) embryos alive.

There is no "need" to ever send a human male. Whenever you want a local source of sperm, you can send any number of male embryos. But again, from a "maximizing reproduction rate" perspective, there is no need to send men. It's far lower mass / higher capacity to send embryos, by many orders of magnitude. And provides the corresponding orders of magnitude increased genetic diversity, rather than having everyone be siblings.

In practice, of course, travel to Mars will be an equal opportunity endeavour.

Shame about the atmospheric pressure and temperature... I mean, if you're a deep sea fish who likes it HOT, sure. No oxygen, either.

Why do people automatically think of planets as only existing at their surface? Yes, the environment at Venus's surface is hell. But in the cloudtops (specifically the middle cloud layer), it's the closest place in the solar system to Earth outside of Earth. Earthlike gravity, temperature, pressure, sunlight levels, and a radiation shielding equivalent to having several meters of water overhead. Yes, there is some (sparse) sulfuric acid mist, like a bad smog/vog, but then again, skin contact with Martian dust will also burn you (due to its oxidizing salts it's been described as similar to handling lye), and probably a lot faster. You can't breathe either of them, but the water won't boil out of your skin on Venus. It might well be possible (although inadvisable) to be outside in Venus with nothing more than a full face mask; contact dermatitis at those sort of H2SO4 levels will happen eventually, but not quickly. You could actually feel an alien breeze on your skin. In any case, no pressure suit is needed.

Not to mention that normal Earth air is a lifting gas on Venus. Or that H2SO4 is more of a resource than a hindrance (there's no shortage of plastics that tolerate it well, it's easy to adsorb, and it's easy to thermally decompose into water, oxygen, and SO2, as well as being one of the most important industrial acids; most of the other major industrial acids are also available straight from the atmosphere, in lesser quantities)

Access to the surface is more difficult than on Mars, but not impossible. Surface probes thusfar have used what humans would need to use to survive: the simple combination of insulation and thermal inertia. Probes have survived for over 2 hours in that manner, and it's possible to engineer to even greater survival times. These were in the lowlands as well, where the air is hotter and thicker than in the highlands. Soft suits would not be viable; as the environment most resembles deep sea diving, you need hard suits. Hard suits were actually prototyped by NASA for use with Apollo, and worked quite well (they're less restrictive to movement than soft suits); however they went with soft suits because they were lighter. One neat thing about operation near Venus's surface is that flight is very easy. Any manned suit at the surface would almost certainly be paired with a bellows balloon, which is an metallic accordion-like adjustable-lift system (which has already been prototyped and tested in Venus surface conditions)

All of that said, there's not really any good reason to put people on the surface, as you can teleoperate dredges for mining the surface (operated from the cloud deck) without any meaningful delay.

Right, but the former royals would keep the money that now goes back to the state.