What goods would be worth trading between Earth and Mars?

Question

Mars is a cold, inhospitable, slightly damp ball of rock that would be very difficult to do things like grow crops on. However, it's also very far away. Far enough that, presumably, it would probably still be worth finding a way of growing them there, rather than shipping them from Earth.

Assuming that I've got technology several centuries more advanced than what we have now, (so probably fusion propulsion, big space stations, and space elevators), what sorts of goods would be worth trading between Earth and Mars? How much would something need to cost for it to be worth shipping it between planets?

Note: I've added the hard-science tag to this question, so answers should be based off of hard data about space flight, rather than pure conjecture.

Answer 1

A lot depends on whether there are still "Martian environmentalists" preventing you from strip-mining the place. If there aren't, and it's increasingly difficult and unpopular to mine on earth, then it becomes worth looking for gold, platinum and various rare earth metals that are useful in small quantities like indium and gallium. You can mine cheaply and pile up arsenic-ridden mine tailings in the sure knowledge that there is no life to poison and no water to leach into.

Another viable export of micro-nations is financial services and tax evasion: the ultimate offshore bank account is on another planet. You could even mine the gold and sell claims over some of it without it ever having to leave the planet. As long as there's confidence that you can ship enough of it back on an ongoing basis.

Answer 2

Martian Imports:

• Complex electronics: Computer chips for example probably will need to be imported, but many other electronic devices (or components for them) will be cheaper to import than build the infrastructure to build natively.
• Complex machinery: While 3D printing keeps improving some machine parts, especially those with especially high tolerance levels will still be cheaper to make on earth using already developed technology and then transported.
• Luxury Goods: that can't/aren't created natively.
• Luxury Food: that can't be grown on Mars.

Martian Exports:

• Data: This one will be easy, but is worth noting even if it's in the form of an 5 Terabyte HDD going back...
• Souvenirs: Who wouldn't want their own martian rock?
• Luxury Food: Martian Whiskey? Martian Corn? People will pay out the nose for the rarity even if it doesn't taste appreciably different.

Trade Both Ways:

• Art and Entertainment: Art will certainly be created on Mars once the population gets high enough, and there will be demand both ways. It will likely be easier for some forms of art to transport rather than broadcast ...especially movies ( cough Porn) where there is a high desire for HiDef quality.

Answer 3

Perhaps focus on what technologies could make interplanetary trade more affordable. Here are some examples:

• Grain and other goods might keep indefinitely once vacuum packed (in space) (assuming you handle the packaging right). So time to trade might not matter. 20 year flights of unmanned cargo pods might be acceptable.
• Unmanned vehicles could be sent slingshot-style, slow-boat style, back and forth. They could be captured on the other end. Trading doesn't have to be fast. Goods could last for years--perhaps decades--while floating slowly between planets. Assume that you can manufacture cheap vehicles, pack them full of pellets of rare ore and vacuum-packed grains, and use minimal fuel to send them on their way. Good calculations would mean no corrections would need to be made in-flight. For example, a rudimentary carbon-based shell could be manufactured easily with minimal cost, be light, and strong. Fusion based detachable engines could start the vehicle going on a 3 to 20 year journey to Earth, then detach, turn around, and capture the next incoming "pod" from Earth.
• Perhaps they invent something like the stargate, but a rudimentary version that only works in vacuum space (safely away from the planet) and that tends to break things apart in-transit. Such a wormhole might only be useful for sending raw materials and grains across (where you don't mind if they get a bit ground up or broken along the way).

Answer 4

To Mars: Life

What Mars doesn't have is biological life and the products that come from it.

Soil: I don't care what Mark Whatney says, you can not make large volumes of soil with poop. Martian 'sand' is actually a fine dust, and while hydroponics will get you so far, there will be a time when people will want to plant with rich soil. The first real tree, for example. Soil takes generations to make by itself, with worms and bugs breaking down plant matter, and yes, dead things and poop enriching it.

Even with human intervention, "making" soil to the quantities that Mars needs will be close to insurmoutable. Heaps of soil could come from Earth to get it started, as well as the types of compounds that can help make soil out of Mars' fine dust and regolith.

Petroleum: Even if all of your energy sources come from the sun, you'll still want to make plastics on-site at Mars. Petroleum comes from dead things, as a fossil fuel, that Mars presumably doesn't have.

Life: It's fun to grow your plants animals and population, but it's a lot quicker to import a lot of that.

From Mars: Service Economy & Logistics

Intellectual capital: Mars will need to diversify, because it really doesn't have much going for it. However, there will presumably be a lot of scientific research that can be conducted there, that can't happen on Earth (because of Mars unique atmosphere, etc.), especially just furthering our understanding of living in space: psychology, physiology, and all the sciences related to space life and travel.

Tourism: This should be pretty self explanatory. Today, a honeymoon at the Maldives (or any remote location) could run an American couple ten thousand USD or more. If that's the same cost in the future to get to Mars, I WILL PAY.

Transportation (& Logistics): Mars is a nice enough stepping point to other places in the solar system. The Moon or other places might be better in terms of their makeup, but your question presumes a population of skilled people on Mars. Dubai was about to run out of oil, so they invested in making themselves into a massive hub of trade and transport, some would argue successfully. Mars with limited resources will have to do the same. Be a desert planet that booms into a major center.

Communications: Mars could establish itself as a center for communication between the inner planets and the outer planets, and can also invest on being a focus of arts & entertainment like aslum said in her answer.

Answer 5

What goes to mars is easy to envision, lots of products that require a big production base, ie electronics, at least at the beginning. Luxury items will always be in demand, and Mars it could be something as simple as 'fresh' fish. While fish are easy to grow, they do need a lot of water.

What can Mars produce that Earth would want back? That is a little harder. There are always raw materials, and Mars is much closer to the asteroid belt so asteroid mining I think will be a big issue for Mars, especially with the idea of bring asteroids into orbit to be mined. Mars itself has a much lower escape velocity so mining materials on the surface might become financially feasible, but raw material is probably going to not be worth the lift fuel. So not only do you have a chance to get good raw materials, they could do better and start building space stations/space ships, it could be much cheaper since they won't have to lift much of the material out of a planetary gravity well. So it might come down to fuel, where can it be found and what can be used.

Answer 6

Earth -> Mars trade is going to be "almost everything" for a while, with emphasis on things that can't be done on Mars. Over time as corporations begin to develop Mars, heavy equipment and things for making things are going to be the main export. Mars has untapped minerals, so something to take those minerals and turn them into goods that can be used on Mars without having to boost them from Earth's gravity well is going to be attractive.
The other thing that Earth will export to Mars is people. Mars has a lot of land, and with no oceans it's pretty close to the same dry surface area as the Earth.
It'll start off slow, with scientists doing short duration stays like the ISS.
Then they'll find something interesting, and the corporations will decide to get involved. They'll try to do as much automation as possible, but there will still be humans sent for short periods to set up and maintain everything.
Eventually it'll become practical to start sending administrators and support staff, and then families will begin to arrive. Meanwhile, there are a few nations with space programs that are severely over crowded, and they'll start to see Mars as a great dumping ground for the people they don't want.

Mars->Earth Trade is a little unbalanced.
Minerals is the first obvious answer, though those can be gotten from asteroids cheaper, and without the pesky and expensive gravity well. Heavy metals like iron, nickle, gold, and things that the asteroids are rich in wouldn't be worth it, but any rarer minerals used for production like lithium might be worth the cost of shipping.
Anything that isn't rare raw resources can be gotten a lot cheaper and easier here on Earth. The biggest thing that Mars has to offer is a new frontier, since we're running out of those down here.

Answer 7

Looking at analogous situations in Earthy history, high value goods and services which are compact and easily shipped were the driving forces of international trade.

People in ancient times traded spices, rare plants, gemstones and other luxury items over long distances, since these more than repaid the costs to transport them. We not only need to comer the costs of the ships, sailors and the various support items (everything from food and water to bribes for the local potentates and customs officers), but also the opportunity costs. The merchant princes have invested a great deal of money in the expedition, and now their reserves of cash on hand are depleted or expended unless the ship comes back with a very valuable cargo to cover the expenses and the interest the money could have earned if it hadn't been used to finance the expedition. In ancient times (and indeed unit fairly recently) if the ship sank, was captured by pirates or the trader was a dud then you were out of all your investment.

Mark Watney aside, traders in interplanetary merchandise won't have to deal with piracy or most of the other hazards of maritime trade, but they will be up against compound interest. Using minimum energy transfer orbits, windows for trade open roughly every two years between Earth and Mars, and transfers will take about 180 days one way. Mars will need "finished" products which require a large industrial base, such as computer CPU's. Shipping raw materials from Mars is a bit silly, except for water, which is useful as rocket fuel for ships returning to Earth (in which case the "trade" is the rocket fuel is purchased at Mars rather than shipped).

Items from Mars will be mostly intellectual property; new ways to utilize in situ resources on Mars, genetic engineering of plants and animals to survive Martian conditions and advanced closed ecological systems for Martian habitats. Some of these ideas are reverse engineer able for conditions on Earth. The other thing that Mars has plenty of is land, so people will be paying handsomely for Martian property, either to live on by themselves or as investment property to rent to prospective settlers.

Answer 8

Various answers listed things based on mature civilization vs colony, but I don't see any quanification of actual costs.

There are three legs of the journey: launch, transit, and EDL.

Wikipedia has a treatment on delta-v between Earth and Mars. However, the difference is not that great as far as these things go, and future technology will have practical solar sails, ion drives, or whatnot. For goods that can be shipped slowly, we can suppose transit shipping is cheap enough.

Lauching a payload from Earth to orbit takes a great deal of energy, and must be done rapidly to have any effect at all. A soloar powered ion drive won't budge if it can't overcome the 1G holding it down.

Short of a space elevator this is a real problem. Can you devise a plausible future launch system that doesn't pollute greatly or doesn't expend waste heat, which itself would be an issue if done on an industrial scale?

Entry, descent, and landing will be easier by using atmospheric breaking, but that requires having a heat shield of some kind and will dump the kenetic energy into the atmosphere.

The escape velocity from Earth is 11.2 km/s, while for Mars is only 5. Mars is much easier to get off of by a factor of 2, and the thin air and open land could make a mass driver launch system practical. Landing on Mars is easier in the sense of how much energy to shed for the landing part, but harder because of the thin air so aerobreaking of any kind is more difficult.

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Getting things off the earth will be expensive. Raw materials are better sourced from asteroids or the moon. Any goods will be expensive to ship, far in excess of their cost. So sending garlic or beer will be prohibative.

Earth might get left behind as a trade partner as the space industry develops! Industry will move to space, and once anything reaches Earth it probably won't leave again.

Answer 9

As others have stated before me, soil, technology and biomass to Mars. In the beginning mainly minerals from Mars.

Space Elevators are the key here. Once you have them in place the cost of lifting stuff out to orbit plummets. Stuff going down (we're surely mining the asteroid belt for minerals and ice) can offset the weight of stuff going up. Shipping 1000 metric tons of soil to Mars then becomes just a matter of putting a big enough container in orbit around the earth and then give it a gentle nudge in the right direction and wait.

If we don't have space elevators... I suppose refined minerals of high worth can be exported from Mars and essential technological components from earth. But I think it'll more be a costly colonization effort rather than a viable two way trade.