Assuming we are able to get a somewhat self sufficient mars colony up and running but with very limited exchange of people and cargo between earth and mars and with the 2.5 year gap between reasonable launch windows. Is there a basis for currency exchange between the planets? Or would they be pretty much isolated economies where earth money is worthless on mars and mars money is worthless on earth?
First, I would question whether your scenario is plausible, in that I think a viable Mars colony would both require us to have forms of transportation that don’t rely on the once-every-2.5-years-window, and would enable us to do so.
Traveling from one planet to another can be done in a few different ways. You could plot these ways on a chart that compares time to destination with dV (change in velocity) used.
On one extreme, we have a Hohmannh Transfer.
This is where you nudge your orbit around the sun outwards so that it juuuuust reaches Mars’ orbit at the exact place and time where Mars itself will be. We can use Earth’s gravity to help put us on this trajectory by making the insertion burn close to Earth’s gravity well. You slowly coast along your orbit until you meet Mars, at which point you fall into Mars’ gravity well. If you aimed right you’ll be on a trajectory that carries you right past Mars (maybe grazing it so closely that you enter the atmosphere and aerobrake); from here, just a nudge will slow you enough that you remain in orbit.
Since you’re using the minimum amount of energy to just coast to Mars, there are two big limitations. You can only leave at a very specific time, where your coasting will carry you to the right place (IIRC Earth has to be about a quarter rotation ahead of Mars; your slow transfer will mean that when you reach Mars’ orbit Mars will catch up).
At the other extreme is a direct burn. This is where you aim directly ahead of Mars (where it will be in a couple weeks) and hit the gas. You don’t let off until you’re halfway there, at which time you point dirsctly away and hit the gas again (to ensure you don’t slam into Mars at relativistic speeds). There are, of course, no brakes in space; so hitting the gas backwards is the best you can do.
A direct burn would only take only a few weeks to reach Mars and return, and could leave at any time (the only probelm would be if Mars was directly on the other side of the sun, but you could just swing around the sun as closely as you can safely get to it and pick up lots of extra speed by doing so). But it would require an engine that can burn for so long, which would pretty much require something like fusion power.
However, there are many points along the continuum between Hohmann transfers and direct burns. A NERVA engine could do it in a month, and larger chemical rockets could also do somewhat better than a coasting trajectory. But all of these things are difficult to build on Earth and bring to space.
However… if we had manufacturing capability in space, we could build the sorts of crafts that let us get to Mars in weeks or months rather than years, and which do not care too much about transfer windows (there will always be more efficient times to go to Mars, but with good enough rockets we could send inefficient trips when necessary).
So I think a Mars colony will only exist when travel to Mars does not strictly rely on transfer windows (even if eg cargo is always sent with super efficient freighters that do make use of transfer windows).
As for whether this will have an impact on the economy - certainly to an extent, but most money is digital, and the delay on the transfer of digital information is only a minute and a half to three minutes, depending on where Earth and Mars are. (Presumably we would have solar satellites to ensure communication continues when Earth and Mars are directly opposite the sun, although this may increase the light lag slightly).
We should consider what would actually be getting traded. Mars would need elements like phosphorus that are necessary for life but hard to come by in space, as well as complex machinery they can’t make onsite. What can Mars provide? Well, to Earth, not much. But the big benefit of any space colony would be its ability to put raw materials or manufactured goods directly into space. It is much easier to leave Mars than it is to leave the Earth, so anything that needs to end up in space is better made on Mars.
[It’s even better to make it in space directly, or on an airless body. So I’d assume a space station or moon base is more likely than a Mars colony, which is more of a vanity project. But we will assume that Mars is the only off-Earth colony, so it would have the space manufacturing advantage.)
So Mars would import a couple things from Earth, but as much as it can would harvest resources and manfuacture things on site. Mars’ biggest export would be helping to put more things out in space. Mars’ mines and factories would gove Earth orbital solar power, access to the raw materials of the asteroid belt, etc.
Like I mentioned, transfer of cargo would likely still be done on slow transfer orbits. So someone on Earth might buy iron futures from a Martian company, purchasing the rights to a shipment of iron that’s coasting through space and will arrive in Earth orbit two years from now. By the time the iron arrives, it may have been sold and resold a dozen times.
And of course the sale of intellectual property can continue unabated. A Martian could stream mobies or download games on Steam (although their library may be limited to whatever the servers on Mars have copied over from Earth. Maybe if you want to download a movie or game that isn’t on NetflixMars or SteamRed, you have to wait a few weeks for the data to be transferred, or (depending on how valuable interplanetary data traffic is) you might be better off paying someone to ship you a flash drive on the next phosphorus and fertilizer freighter from Earth.
Now I’m picturing the epic whining of earthbound gamers getting matched with Martian gamers in the same team lobby.
“370,000 ms ping? Dammit, I hate getting matched with Marsies!”
Hillarious as that sounds, I would guess that each planet would have its own “internet” with locally hosted websites accessible by planet-bound users. Space stations in orbit of a planet could use the same network, but space stations out in the asteroid belt would probably be on their own.
Some sites might get synched with their Earthly equivalent on a regular basis, but live interaction between planets would be impossible.
Currency exchange doesn’t have to be piles of cash shoved onto a star-freighter. We can do bank transfers over the internet with our current technology. Something similar could be done between Earth and Mars.
Some things would have to be done differently. When it takes anywhere from 5 to 20 minutes for a radio signal to get from one planet to the other, that makes it more than a little impractical to have your Interplanetary Express Card send an authentication request all the way back to the bank’s server back on Earth. Crypto-currency type “wallets” could be used to carry money with you from one planet to the other, and the banks would probably only need to settle up once a day between the two planets.
There’s no reason for the two economies to be completely isolated.
Even less fuel than a Hohmann trajectory would be using an Interplanetary Transport Network - Wikipedia trajectory to get from an Earth-Sun Lagrange point to a Mars-Sun Lagrange point (or a Mars aerobraking trajectory). However these make Hohmann trajectories look like FedEx overnight delivery by comparison.
I suspect that for a long time a Mars colony would largely operate on the basis of “shipped from Earth” credits: how much people had in Earth-based bank accounts to pay for stuff to be shipped to Mars, since at least at first very little other than air, water and construction materials would be produced locally. Even things like food or machined objects would probably be priced in terms of depreciation of equipment wearing out that will eventually have to be replaced from Earth.
If we really do get to the point where we actually have an interplanetary economy, an accepted standardized crypto currency setup seems logical to me.
They still could be useful for sending cargo. And like I said, even if the cargo is en route for years, it could be getting bought and sold along the way, like any other reserve of assets.
You could even set up a Cycler - a station in an orbit that regularly carries it past Earth and Mars.
If you set up a solar or nuclear powered metal refinery on a cycler, for example, you could conceivably coast to Mars, pick up raw materials, coast to Earth, refine the metal on the way, get to Earth, sell some of the metal and buy complex technical parts, the coast to Mars while assembling complex machinery using your raw materials and the inserts acquired from Earth.
In fact, it would be impossible for them to be isolated, otherwise you’d never get a “somewhat self-sufficient colony” established in the first place. Mars will rely on equipment and personnel from Earth for decades or centuries before they can be self-sufficient. That means there needs to be some way for Mars to pay for that kind of thing.
By the time Mars could hope to stand on its own for even the basic necessities of life, the banking system would be quite well-established.
And even after Mars no longer needs material wealth from Earth, there will still be exchanges of intellectual property. Patents, copyrights and the like. All that will have value, and need some means of interplanetary commerce.
You still have to match trajectories with a cycler orbit. Their main attraction is in terms of habitation facilities for the trip: you don’t have to reboost habitable volume every new trip.
Right, but you’re just sitting around during the transfer. With this proposal you’re doing useful work (refining the product from Mars > assembling the components from Earth) which might be desirable.
Um… no.
When Mars and Earth are at their closest it’s 3.03 minutes (182 seconds). But they aren’t always that close. One average the time-delay for light-speed interactions is around 12 minutes, and at their most distant points it’s 22.4 minutes.
Not an insurmountable delay, but I did want to keep to the facts.
Whoops, you’re correct - I misread the chart I got my numbers from.
So yeah, no interplanetary FPS games (you could play Civ by email).
A website like this one would probably not go interplanetary. Imagine the headache of having to merge posts from two different versions of the thread every hour or so! It would be a mess.
Of course, who knows what the internet of twenty-Martian-three will look like. It seems like there’s a general trend of moving towards asynchronous communication, but the internet is also not very old.
I’m thinking Martian beaver pelts
Why would threads have to be merged? There’d be more ninjaing, but if you make a post to version 1 of the thread, it’d still go to that thread, eventually.
Would posts just go to the bottom of the thread however many hours later? Or would they go where they would slot linearly?
They would show up in the order that the server received them. Just like they do now.
Is it possible to have the posts appear in the time-order based on the user’s time stamp for when it was sent?
Wouldn’t that mean that it would take 20-40 minutes for me to see my own post if I’m on Mars? As well as the posts of other Martians?