3 ms·
Mars has half the escape velocity and a much thinner atmosphere. Just from the ideal rocket eqn the same reusable rocket flying from Mars can lift more than 4x
by nickparker 8y ago
Mars has half the escape velocity and a much thinner atmosphere. Just from the ideal rocket eqn the same reusable rocket flying from Mars can lift more than 4x the mass it can on Earth, and the comparison is even better when you look at drag and engine efficiency differences.
I don’t have the expertise to really compare asteroid mining to Mars, but I’m suspicious of the fixed infrastructure costs. Mining and refining takes a lot of mass. Replicating that mass for each object you want to mine or flying it from rock to rock both seem like significant costs. Perhaps we’ll find a big Goldilocks rock that’s near Earth, will stay near Earth for a long time without insanely expensive capture maneuvers, and contains all the materials we want, but I think Mars has a better shot.
Mars also has much friendlier conditions for propellant manufacturing, which is an important factor in these cheap launches.
- Nokinside 8y agoMars is red because metals in mars are oxidized (iron regolith). Removing that oxidation requires energy. Just as on earth, most valuable metals are likely deep under surface. Metals on asteroids are easier to extract. Some asteroids, like 16 Psyche are almost solid chunks of metal. Asteroid ice (oxygen and hydrogen) can be turned into rocket fuel with electricity from solar panels. Single asteroid close to the Earth can supply all the needs on earth for centuries.
- nickparker 8y agoOnly the very surface is red[0]. Martian crust is fairly normal rock underneath as I understand it. 16 psyche is one of the 10 most massive objects in the belt. The belt is more than twice as far away, and transfers to it are much more variable over the years than the fairly regular Mars windows. Finding the “Goldilocks” object that supplies all our needs, can be regularly reached economically, etc etc isn’t an easy problem. Also, water gets you hydralox propellant, which is a bit of a pain in the ass. You really want organic compounds too so you can do methalox, which is one more constraint on Goldilocks. [0] https://m.phys.org/news/2013-05-curiosity-mars-rover-drills.html https://m.phys.org/news/2013-05-curiosity-mars-rover-drills....