Comments on: The Challenge of Mars Mining

By: Phil Metzger

Phil Metzger — Thu, 09 Jul 2015 16:00:20 +0000

Hi Chris,
I think the problem will be that the methane can’t be used without oxygen, and the oxygen needs to be made on Mars, as well. So rather than hauling around liquid oxygen tanks (with active cooling systems) on all the robots, it is easier to use batteries and then recharge at the central energy system near the mining site. What about using methane at the central energy system? Well, making methane requires energy, and we will use either nuclear or solar energy for that task. So methane would be a method of storing the energy. If we have a nuclear system then we could probably just recharge the robots directly from that, but if we are using solar then we do need an energy storage system to get us through nights and dust storms. Methane (chemical) energy storage is one possible solution to that. We will probably be making methane as the propellant for rockets leaving Mars. Methane is more storable than hydrogen.

Another strategy is indeed to put fuel cells on the robots and use liquid oxygen. Normally hydrogen is used in fuel cells. We demonstrated a rover with hydrogen/oxygen fuel cells in a field test in Hawaii a few years ago. There are ways being developed to store hydrogen more safely for vehicles. Maybe methane could be used in a fuel cell — I have no idea since I’ve never investigated that technology. It would certainly call for a trade study to see which system makes for the best robots. I know that mining on Earth is now sometimes using fuel cells. Deep in the mines they don’t want vehicle exhaust, and fuel cells only put out liquid water so they are a good solution for terrestrial mining. Maybe they will play the same role in planetary mining.

Good thoughts!

By: Phil Metzger

Phil Metzger — Fri, 29 May 2015 04:40:23 +0000

Hi Chris,
yes, we could build machines on Mars since the minerals contain metal. However, it is a supply chain problem. The many different materials and parts in a complex vehicle all have to be made using other machines, each with their own different materials and parts, and so on. Ultimately, it takes the industry of the entire world to support the industry of the entire world. What is the smallest subset of industry that we can send (reasonably) to Mars? I think for starters we could send a machine to make a crude metal from Martian minerals in the soil, and we could 3D print parts with that. But we would probably need to send many of the components of a mining vehicle (like the electronics and soft goods) from Earth.

Yes, we could use methane to power a vehicle. But remember that we also need oxygen to burn the methane, and there is no free oxygen in the Martian atmosphere. We would get oxygen as a byproduct of making the methane, anyway. We would have to bring both the methane and the liquid oxygen in tanks on the mining vehicle. They could react in a fuel cell to make electricity for the mining vehicle’s motors. I like your idea of a dedicated refueling vehicle.

By: Chris Marshall

Chris Marshall — Wed, 27 May 2015 14:21:21 +0000

Thank you for the information I am very interested in Mining both on Mars and Asteroids.

Would it be possible to manufacture parts for large mining vehicles at Mars itself? This way we could send up the necessary equipment to do the manufacturing and then build the vehicles needed once there.

Also a question about Swarms of vehicles, could these be Methane powered? One scenario that seems logical to me is to send a Methane plant to the surface which generates the fuel, there would be a couple of vehicles in the swarm dedicated to refueling the actual mining vehicles. These would then not need to move away from where they are mining, other vehicles in the swarm would transport the mined materials for processing.