Far as weight goes, wouldn't 1-2.5 tons of payload capacity per person be enough? And as far as volume is concerned, I'm pretty sure there's lots of ways to increase that dramatically while you're in space (e.g. inflatable habs). All you really have to do is figure out how to keep them comfortable until the starship is outside the atmosphere and whatever larger spaces have been constructed/inflated.

> Far as weight goes, wouldn't 1-2.5 tons of payload capacity per person be enough?

IIRC you need 6 tonnes of food and oxygen just to keep them alive for the transit.

Solar-powered electrochemical synthesis of small energy source molecules like glucose or acetate might reduce that substantially. If you supply 80% of the energy demand that way, you'd easily half the "proper food" mass that you need to ship.

> Solar-powered electrochemical synthesis of small energy source molecules like glucose or acetate might reduce that substantially.

Has that ever been done for human consumption before? Relying on a novel technology in a setup where, if it breaks, everyone on board dies, seems rather dubious.

That's not even being studied right now so give it 20-25 years before it's even considered as a long term diet. Also we have to keep them sane as well as simply alive and good food is a big part of long term mood maintenance. You're going to be asking people to eat this for at least 7 months if it's a 1 way trip and you have a working food system on the other side.

https://doi.org/10.1038/s43016-022-00530-x feeds nutritional algae, yeast, and a variety of mushrooms ( pearl oyster, blue oyster, elm oyster, coral tooth and enokitake), though the mushrooms were tested with a simulated (I assume this means petrochemically derived, purified, and reconstituted to match the real mixture) analog of the real electrochemical acetate feed, which they tested with the first two organisms.

There were also experiments with "undifferentiated lettuce tissue", using C13-labeled acetate to investigate whether crop plants are able to properly feed off of acetate as their main food source, instead of photosynthesis-based small molecules.

What I'm suggesting is, roughly, to replace the base starch and maybe (some amount of) base fat in a diet (think a typical Asian diet's rice, or wheat in (historic) European bread+beer[0] diets), so that the overwhelming amount of calories won't need to be supplied in advance. Yeah, that'd likely involve feeding some algae or so with the e.g. synthesized acetate, due to yielding nicer nutrition molecules than e.g. simple glucose, which would be comparatively feasible to synthesize without having to use a bio reactor.

Worst case you'd have more sleep in place of productive work for energy conservation reasons, if you need to partially fall back on shipped food due to the food synthesis machines breaking. Recent space fairing history has shown that we can make machines very reliable, especially if they're pretty self-contained, not exposed to/operated in vacuum, and straight-forward to test on earth and in low earth orbit. The ISS crew is just too small to warrant as much of a kitchen facility as needed for incorporating something like "algae-based rice-substitute" or "mushrooms" into their meals, but if Starship works well enough to deploy an unmanned algae production machine for a few months (with solar panels and thermal radiators), before transferring the produce to the ISS to test zero-G food preparation...

[0]: that beer was really low %ABV, and more comparable to eating bread with 1:1 watered-down beer to wash it down.

For an Apollo-grade flag selfie and back? I'd say 1-2.5 tons are plenty. Anything more than that, certainly not.

Man, the whole Mars thing really irks me. I have yet to see any Mars colonization plan which accounts for galactic cosmic radiation (heavy ions traveling at 99+% the speed of light which suffuse space outside of low Earth orbit). Traditional radiation shielding is not very effective against them and in some cases can make their biological effects worse—the particles hit the shielding and turn into a shotgun blast of high-energy decay products which are even more likely to interact with the non-relativistic atoms like, say, astronaut DNA. I will not take anybody's proposals for colonization of another solar body seriously until they have a real answer to this problem, and I urge you not to either.

"During transit outside of LEO, every cell nucleus within an astronaut would be traversed, on average, by a hydrogen ion every few days and by heavier HZE nuclei (e.g., 16O, 28Si, 56Fe) every few months. Therefore, in spite of their low flux, HZE ions constitute a deleterious biological threat and contribute a significant amount to the cumulative GCR dose that astronauts will incur outside of LEO."[0] (emphasis mine)

These particles are everywhere, they come from no specific direction (hence the designation "galactic"), and represent a significant threat to any living creature in deep space. To avoid them during long-term occupation of the Moon or Mars, we'd have to live deep underground. By some estimates, even a one-way trip to Mars could prove fatal to a significant percentage of those taking the journey.

[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4206856/

Just imagine only sending 20 people instead of a theoretical 100 people in a single starship out of an armada of starships to mars. Would it even be worth the trip if we landed only 20 people per ship? That would make actually landing on mars such a failure

The problem is that you won't get to send twenty people either...

Yeah. Sending 3 is reasonable and would advance Mars science by 100x (10x the first day with a shovel) but dude rants about cities. Nice to have a vision, I guess? But maybe let’s try with 3 first.

Send a pile of good robots and tools there first.

Build a lab. Run it with things that we hope are good enough, but don't value enough to get home (back to earth) safely.

If we're really smart we can even use the whole thing to bootstrap a useful environment to get to and a far easier environment to get back from.

It's been 12 hours, so rather than an edit to elaborate I'm adding a reply.

I mean very different robots from the rovers we've sent to date. Maybe not even more complex robots but definitely bigger (and smaller too) robots.

Their task not to survey with minimal disruption, but to actively disrupt. To build, to transform materials (lab), to create the base buildings and infrastructure of civilization. So there's somewhere with resources to better support humans.

Until now, rockets have been produced "by hand", one by one. And you get handcrafted prices for rockets. To lower pricing, and revolutionize space travel, you need a production line of rockets. What will you do with 100s of rockets of this factory ?

Also, you need a vison to advance things. Millions of electric cars ? 10 years ago it would have been a joke

> Millions of electric cars ? 10 years ago it would have been a joke

Viable electric cars were a thing even way back in the late 19th century [1]. The problem was that burning oil was cheaper (as the users had to pay none of the externalities for decades), and so it lost out for a good while despite being more efficient (i.e. energy contained in the fuel vs distance driven) on paper.

On top of that came the massive, decades-long lobbying efforts of the fossil fuel industry to get rid of public transit.

[1] https://en.wikipedia.org/wiki/History_of_the_electric_vehicl...

The electric cars of the late 19th century were extremely slow and limited in their abilities. Of course, gas cars were too, but they advanced quickly, because there's SO much energy stored in gasoline and diesel fuels. Electric cars, I don't think, could ever have progressed that far until recent times, because batteries just didn't have enough energy density to make them practical (in the way that cars of, say, the 1970s-90s were practica), until Lithium-ion batteries because cheap and commonplace, which was only in the last 20 years.

> The electric cars of the late 19th century were extremely slow and limited in their abilities.

Agreed on the speed, but 100 miles range on a single charge? That's more than enough to account for the needs of the vast majority of commuters.

> until Lithium-ion batteries because cheap and commonplace, which was only in the last 20 years.

I wonder how that one would have played out if we didn't have oil. The abundance of cheap fossil fuels didn't make it exactly worthwhile to invest in battery R&D.

>Agreed on the speed, but 100 miles range on a single charge? That's more than enough to account for the needs of the vast majority of commuters.

1. If that were true, EVs would have been much more successful in America. They haven't been. The Nissan Leaf was around long before Tesla and it never went far, because the range sucks.

2. Back in 1900, 100 miles would have been great. In 2000, it's not sufficient at all for most car-owning Americans.

3. You can't have the same range at higher speeds: energy usage goes up dramatically with speed. So you need much more energy storage, and the battery tech of the time just wasn't sufficient.

>I wonder how that one would have played out if we didn't have oil. The abundance of cheap fossil fuels didn't make it exactly worthwhile to invest in battery R&D.

That's a very good point. It would be interesting to see an alternate universe where this was the case.

100 miles is good for commutes but commutes aren't the only use people have for cars. Vacations are something that even if the US doesn't get to take as often as we should people still aspire to them and the further you move up the income ladder the more they happen. 100 miles isn't enough for that, so you'd have to either have a second car that's gasoline powered, a more capable long range vehicle, or rent a car for those trips.

100 miles is not sufficient for commutes in America these days. Many people drive more than 100 miles in a day. Even if they don't do it every day, the drive to/from work plus an extra shopping or social trip in the evening could easily put them over 100 miles.

The problem is that, because of cars, they built everything farther apart, and people willingly chose places to live farther away from work. Just look at a map of the city of Phoenix AZ for instance: 100 miles' range won't cover a trip from one side of the city to the other side and back.

However, for vacations, a rental car is absolutely the right idea. That's what people here in Tokyo do: there's lots of convenient places to rent a car for shopping trips to Costco, or a trip to the mountains, etc., because so many people don't own cars.

> Millions of electric cars?

Electric cars are nice and all but if you want to credit Elon Musk with contributing to the switch from gas to EV, you also have to credit him with killing high-speed rail with spitballing about the vaporware that is building underground vacuum tunnels to shuttle cars around, aka the Hyperloop (before it became a closed-loop underground taxi service with no regard for fire safety).

Also the classic rich guy idea of reinventing buses/trains but worse to "solve traffic" without having to risk sitting next to another person. That's a foible not unique to Elon though.

The problem isn't purely solvable by the number of rockets we can produce. Mars is wildly inhospitable with the majority of the soil being poisoned by perchlorates, it's a convenient source of oxygen but it also means the soil needs to be processed before we could even start to use it as a substrate for crops.

Fundamentally the issue with long term Mars habitation is that any technology that allows us to live on Mars full time without support from Earth would make even the wildest 'destroyed' Earths livable. The only thing Mars gives you is there's not going to be people beating on the outside of your trillion dollar dome trying to get in.

The first human landing on Mars destroys a large section of Mars science forever, because then we can no longer be sure if life traces we find there are indigenous or not.

Slight nuance. We can most definitely tell if a life source you find there is from mars or not - assuming it has the same dna backbone, sequence comparison can tell exactly when life diverged into the two planets (as it likely did if mars ever had life).

The real danger is that life forms hitchhiking the first humans can totally overwhelm any existing life and completely condemn it.

I'm pretty sure that changes nothing and we can still be absolutely sure what we find there is indigenous or not.

I love the idea of humanity expanding out into the cosmos, it feels like space exploration is "the Future." But I can't see how SpaceX's Mars colonization plan makes economic sense in the current day. No matter what technical advances they come up with in getting people to Mars, it doesn't change the fact that it is an inhospitable planet. What unique resources are on Mars that makes it more profitable than say, colonizing the Sahara desert?

People can do both. And more.