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> Why? i'm not a rocket engineer, but at least some reasons are pretty obvious. 1. you need less than half of the fuel. Yes, you will need less fuel to take o

by y4mi 8y ago

> Why? i'm not a rocket engineer, but at least some reasons are pretty obvious. 1. you need less than half of the fuel. Yes, you will need less fuel to take off of mars, but its still a massive amount of fuel you need to safely transport to mars, as its an exponential curve of fuel consumed per kg of fuel transported 2. you don't have takeoff infrastructure on mars. your space vehicle would have to be able to safely lift off without any external help.

walrus01 8y ago
very rough calculations: https://i.imgur.com/SqdzxzF.png https://i.imgur.com/SqdzxzF.png interestingly, while it takes something like 9800m/s delta V to get from earth sea level, at the equator, to LEO, it's more like 3800m/s delta-V required from surface to achieve low orbit of mars. I think most mars return missions presume the ability to produce fuel locally through something like the sabatier process, and not haul it from earth -> LEO -> mars transfer orbit -> mars surface.
- TuringTest 8y ago
  Cool image! That looks like the subway map of the solar system. Is that your own? If so, what software did you use to paint it?
  - walrus01 8y ago
    Not my own, it actually came from a forum for Kerbal space program players who've installed a mod that changes things to a 1:1 scale model of the real solar system.
mcv 8y ago
You may not have to take your return fuel from Earth to Mars. Robert Zubrin's Mars Direct plan is to first send a return vehicle to Mars together with some hydrogen and a plant that generates methane and oxygen out of CO2 and hydrogen. Let it work for two years, then send another one, while also sending the manned mission. If all goes right, the first return vehicle is ready for take off when the manned mission arrives, so they can evacuate right away if necessary. If something is wrong with the first return vehicle, they can spend their planned two years on Mars and by then the second return vehicle will be ready to take them home. Otherwise the second return vehicle waits for the next manned mission.

by y4mi 8y ago

walrus01 8y ago

very rough calculations: https://i.imgur.com/SqdzxzF.png https://i.imgur.com/SqdzxzF.png interestingly, while it takes something like 9800m/s delta V to get from earth sea level, at the equator, to LEO, it's more like 3800m/s delta-V required from surface to achieve low orbit of mars. I think most mars return missions presume the ability to produce fuel locally through something like the sabatier process, and not haul it from earth -> LEO -> mars transfer orbit -> mars surface.

TuringTest 8y ago
Cool image! That looks like the subway map of the solar system. Is that your own? If so, what software did you use to paint it?
- walrus01 8y ago
  Not my own, it actually came from a forum for Kerbal space program players who've installed a mod that changes things to a 1:1 scale model of the real solar system.

mcv 8y ago

You may not have to take your return fuel from Earth to Mars. Robert Zubrin's Mars Direct plan is to first send a return vehicle to Mars together with some hydrogen and a plant that generates methane and oxygen out of CO2 and hydrogen. Let it work for two years, then send another one, while also sending the manned mission. If all goes right, the first return vehicle is ready for take off when the manned mission arrives, so they can evacuate right away if necessary. If something is wrong with the first return vehicle, they can spend their planned two years on Mars and by then the second return vehicle will be ready to take them home. Otherwise the second return vehicle waits for the next manned mission.