Or, just make the vehicle being sent to Mars sufficiently large. Shielding mass needed goes as r^2; vehicle mass and volume as r^3. Just storing the cargo and propellant on the outside of the vehicle and the crew in the center should suffice for a sufficiently large vehicle.
Of course, cost goes up linearly with mass and thus cubed with `r`. Mars missions are expensive enough as it is without making the launch vehicle much bigger than required for the mission.
If going to Mars is worth doing, it's worth doing at scale. Considerations of "it's too expensive" mean one should work to make it cheaper, typically by reducing launch cost. It looks like we'll have launch costs of a < $10/lb to LEO before anyone seriously goes to Mars.
Just say no to flags-and-footprints (and SLS); say yes to large scale Mars activities.
> If going to Mars is worth doing, it's worth doing at scale
I don't think this is true.
If the main value is getting credit for putting the first human there, and doing a few experiments on soil samples or somesuch, then it definitely wouldn't be worth scaling things up, the same way its not worth doing missions to the deep sea, Antarctica or the Moon at scale...
> the main value is getting credit for putting the first human there, and doing a few experiments on soil samples or somesuch...
This is old thinking. I take the goal of self sustainable society on Mars very seriously. Will it happen in our lifetime? Probably not, but it is the goal we should be working towards.
I'm not being snarky (at least not intentionally). But you're saying a thing that is at the very least a superpower-level goal, if not a civilization-level goal, that is very clearly not a current priority, should. What's more you're saying it in a way as if it's completely self-evident that we should change our global priorities to focus on this without the slightest evidence supporting that assertion.
Well where do you see humanity in the future? In a realistic but also optimistic future? To me all of these futures involves us being a multiplanetary species, and starting to expand out into the cosmos more broadly. It's not only the only way we'll ever become a post-scarcity species, but also the only way we can secure our own survival as a species. There have been countless mass extinction events on Earth, and we're well overdue for another one, and it will come.
You're also probably grossly overestimating the cost. The SpaceX Starship program has been privately funded on a budget of ~$2 billion a year including all costs - research and development, construction, launches, etc. And once built it's expected to revolutionize space (again) sending launch costs to less than $10 million per flight, and price per pound to space into the low dollars! And once we can start transiting massive amounts of cargo to Mars, at a very affordable cost, colonization is very much within the domain of possibilities.
I would not contrast prices against NASA. NASA is largely used as a tool for pork and graft by Congress, that occasionally launches something. Their latest ship, the SLS [1], is literally reusing Space Shuttle era tech. I mean literally - the SLS is reusing refurbished Space Shuttle RS-25D engines, solid rocket boosters, and more. Managing to spend tens of billions of dollars over 13 years (and counting) to develop this is the special sort of talent you can only get from a company like Boeing.
So colonization will be costly, but it's nothing like a civilizational goal. It's just that our civilization only has governments mostly interested in fighting and dominating one another, just as has been the case for the entirety of human civilization. So we never really get to see what we could actually achieve if we tried. But what's finally changed is that these sort of grand achievements no longer require governments. Costs are plummeting at the same time private capital has skyrocketed. So the future looks brighter than ever!
You could reasonably define "post-scarcity" as "we've got more supply than we need".
In this regard, you can define scarcity and post-scarcity independently for every consumed resource.
We've been post-scarcity for oxygen since before we evolved; post-scarcity for water in most of the settled world; and now? Now we're post-scarcity for biros, photocopier paper, USB cables and wall-warts, and tchotchkes.
The only reason we're not post-scarcity for intellectual property is that we've created rules to induce artificial scarcity.
>We've been post-scarcity for oxygen since before we evolved
Have we? Our supply has been getting tainted with worrying levels of trace contaminants. If we had 100x as much atmosphere, maybe that wouldn't be an issue yet.
>post-scarcity for water in most of the settled world
"""Globally, 2 billion people (26% of the population) do not have safe drinking water and 3.6 billion (46%) lack access to safely managed sanitation,"""
As you quoted me, most of the settled world. Most. As in, more than 50%.
Personally I feel the main value of going to Mars is figuring out if it has or ever had life. That kind of search will benefit from scale. More tools to do more experiments, range farther from home base, maybe multiple landing teams. We could find ways to use an arbitrarily large payload. I guess that's not exactly what GP had in mind, though.
If you don't think it's a general property of things worth doing, what in particular about going to Mars means it's only worth doing at scale? It's a frankly bizarre claim that you've so far made totally unsupported.
Obviously I meant there are specific aspects of going to Mars that justify the statement, even if I didn't list them. I am not required to laboriously explain the justification behind any statement I make. We could discuss this further if you like. Your assumption that I had no such aspects and meant that as a universal rule is clearly not listening to me in good faith.
It's definitely not obvious if you spout off something that sounds like a platitude without elaboration that you actually only mean something very specific (let alone what specifically you mean), and while you're correct that you're not actually obligated to do so, you should provide some explanation if you have any interest in communicating effectively. Failing to do so is likely to lead to misunderstandings. But you've repeatedly missed opportunities to explain your position, even dodging explicit requests for clarification. That seems more like bad faith than just not reading your mind correctly.
I guess that's where politics comes into play. The reason NASA etc. are trying to push costs down isn't necessairily because it wouldn't be worth it if it was more expensive, it's just that projects that are cheaper have a higher chance of getting funded.
Also, the value of going to Mars is still highly speculative. Once we reach it with low-cost, smaller missions, it's going to be less speculative, and the risk/reward profile of sending huge spacecrafts will make them more viable.
Unless you source the mass from something that's already orbiting, like the moon.
Since we're mostly talking water, any moon water doesn't have to pay the rocket tax to launch from Earth surface.
And for a recurring trip, it'd make way more sense to keep a larger transit ship continually in either orbit or transit, with smaller barebones Earth/Mars cargo/crew transfer craft at either end.
It is hard to pencil out lunar materials being cheap, except maybe for use on the moon. If we're at the point where we are capable of in-situ utilization we probably have some kind of Starship-class rocket. The worst part of the "rocket tax" is not that you have to burn a lot of fuel or screw around with stages and refueling, but rather that you (1) throw the rocket away after one use or (2) it is a Great American Boondoggle like the Space Shuttle.
I do like the picture though of a lunar mass driver that sends up regolith, metal, or something like that to a catcher at, say, the L1 point.
A better option would be near-Earth asteroids. These require significantly less fuel to get to than the Moon and many are rich in ice. If you got really really lucky, you could even find one with an orbit similar to the Hohmann transfer path required to get to Mars and visit the asteroid en route. That way you don't even need to expend much fuel to transport the water to Mars; it's almost free.
For a return trip you could use Phobos and Deimos for material. They are also extremely easy to land on.
So? Do it in multiple phases just like we've done for the ISS. Isn't that one of the points of SpaceX building cheap/reusable rockets that can be launched quickly? Even Star Trek did this.
Which is why minimizing the mass portion budgeted toward shielding makes sense. If you're going to send 10 smaller ships or 1 large one, you better send the 1 large one.
FWIW, my idea of a perfectly reasonable piece of space infrastructure in the multi-planet era has a mass of around 10^11 kilograms. Fortunately, the infrastructure itself can bootstrap in a way that reduced the launch costs to, it is claimed, 9 kWh/kg: https://web.archive.org/web/20120306175303/http://www.paulbi...
