First, they would need to have much better closed systems. At the moment they depend on several tons of supplies every few months from Earth and they dump their own wastes back into the Earth's atmosphere where they burn up and incinerate. Both of those are impossible in Mars orbit or at least very expensive with present day technology.
You can't possibly send tons of supplies every few months to Mars. You'd need to send dozens of tons in one go every two years. But that would be unfeasible also as we probably don't have the launch facilities to send so many rockets to Mars in such a short time interval all at once.
And no way can you burn the wastes in the Mars atmosphere. For one thing the atmosphere is thinner. But also - I'm assuming that we are still in the exploration and planetary protection phase of exploration of Mars - then we don't want to contaminate it with Earth microbes. Hard to be sure you don't do that if you dispose many tons into the Mars atmosphere every few months. I think they'd have to dispose of their waste by sending it totally out of the Mars gravitational field, maybe even return it to Earth. I suppose could crash it into Deimos but I'm not sure that that is a good thing, to make Deimos into a trash dump for human waste from Mars orbit.
So - at least with present day technology that whole model for the ISS is unfeasible for Mars orbit, or at least, hugely expensive.
I think that probably we have to develop ways of recycling just about everything. Grow their own food. Wash their clothes - at present astronauts in the ISS I understand don't wash their clothes, just trash them when dirty and wear new ones. Generate all their own oxygen, in a way that doesn't depend on constant resupply from the Earth. There are ways of doing these things. E.g. using green algae to generate oxygen. The Russians developed this technology on the ground and tested it and it worked. but never flew it in space.
They aren't even really exploring these kinds of technologies for the ISS, not in any serious sustained way. So we'd need to do some long term experiments in LEO or lunar L1 and L2 first.
Then, the crew have to stay healthy for a minimum of two years and a few months as that's the soonest they can get back to Earth if they get sick. I think that this will need artificial gravity myself. Could be zero g plus drugs plus two and a half hours of strenuous exercise each day just to slow down the degeneration of the human body in zero go. But surely artificial g is a better solution.
Two ways of doing that - one is a tether system or a larger rotating spacecraft. One natural way there is to tether the spacecraft to its final stage which goes on a trajectory towards Mars anyway in most ways of launching rockets to Mars. They have to take care the final stage doesn't hit Mars. So why not use it as a counterweight for artificial gravity? Or use small scale centrifuges as part of the spaceship or included within it. This all depends though on experiments into
1. what level of AG humans need for health, and how often (24/7 or just an hour a day say)
2, what our spin tolerances are in zero g
- questions that really need to be answered in orbit as we can only simulate it in a limited and rather uncertain way on the Earth
Then as well as that they need shielding from cosmic radiation, and from solar storms. For cosmic radiation - then if they have lots of water they can use that for at least a two year stay it might be enough. For solar storms, probably need a more highly insulated refuge they can retreat to during a major storm. The ISS doesn't need this because it is protected from the worst effects of solar storms by the Earth's magnetic field.
Then - it would probably have a lifeboat spacecraft permanently attached just as for the ISS. But you'd only be able to get back to Earth every two years at the appropriate launch window. So that's a major difference + the communications.
Would also need to work out better communications with Earth. Probably laser communication? Because you'd need a lot of bandwidth. Probably need to build new radio telescopes on Earth to receive the signals also I'd imagine.
And - the other big difference - your main objective would be exploring Mars, not just studying effects of zero g.
So - you'd have telepresence equipment as standard. I think myself probably have omnidirectional treadmills and VR glasses and haptic feedback gloves. And loads of workstations to control all the rovers and other instruments on Mars. And - once scientists know that their spacecraft can be controlled from Mars orbit, then I'm sure every mission to Mars would be designed for telepresence operation. So that is what the crew would probably spend most of their time doing, unlike the ISS.
I see this as fairly far into the future. At a minimum, you have to have a few years experience of all the relevant technologies in the Earth Moon system where you can have a lifeboat to return you to Earth within a day or two, before it is responsible to risk humans with the same technology to Mars.
Reason being that it would take up to two years and six months to get back in case of an emergency, would take same length of time also to get emergency replacements and other emergency supplies to the crew in Mars orbit. Also you have up to 40 minutes delay between asking a question and getting a reply when you try to get support for maybe some intricate technical issue that you have to solve quickly or you are dead.
All this makes any kind of human occupied space station in Mars orbit many times harder than the ISS, so - I think myself we need to take this one step at a time and sort all these things out in the Earth / Moon system first.
All the same, it is feasible, I think we can do it some time. And far far more feasible and far safer, and also acceptable according to planetary protection than ideas to send humans to the surface of Mars.
You can't possibly send tons of supplies every few months to Mars. You'd need to send dozens of tons in one go every two years. But that would be unfeasible also as we probably don't have the launch facilities to send so many rockets to Mars in such a short time interval all at once.
And no way can you burn the wastes in the Mars atmosphere. For one thing the atmosphere is thinner. But also - I'm assuming that we are still in the exploration and planetary protection phase of exploration of Mars - then we don't want to contaminate it with Earth microbes. Hard to be sure you don't do that if you dispose many tons into the Mars atmosphere every few months. I think they'd have to dispose of their waste by sending it totally out of the Mars gravitational field, maybe even return it to Earth. I suppose could crash it into Deimos but I'm not sure that that is a good thing, to make Deimos into a trash dump for human waste from Mars orbit.
So - at least with present day technology that whole model for the ISS is unfeasible for Mars orbit, or at least, hugely expensive.
I think that probably we have to develop ways of recycling just about everything. Grow their own food. Wash their clothes - at present astronauts in the ISS I understand don't wash their clothes, just trash them when dirty and wear new ones. Generate all their own oxygen, in a way that doesn't depend on constant resupply from the Earth. There are ways of doing these things. E.g. using green algae to generate oxygen. The Russians developed this technology on the ground and tested it and it worked. but never flew it in space.
They aren't even really exploring these kinds of technologies for the ISS, not in any serious sustained way. So we'd need to do some long term experiments in LEO or lunar L1 and L2 first.
Then, the crew have to stay healthy for a minimum of two years and a few months as that's the soonest they can get back to Earth if they get sick. I think that this will need artificial gravity myself. Could be zero g plus drugs plus two and a half hours of strenuous exercise each day just to slow down the degeneration of the human body in zero go. But surely artificial g is a better solution.
Two ways of doing that - one is a tether system or a larger rotating spacecraft. One natural way there is to tether the spacecraft to its final stage which goes on a trajectory towards Mars anyway in most ways of launching rockets to Mars. They have to take care the final stage doesn't hit Mars. So why not use it as a counterweight for artificial gravity? Or use small scale centrifuges as part of the spaceship or included within it. This all depends though on experiments into
1. what level of AG humans need for health, and how often (24/7 or just an hour a day say)
2, what our spin tolerances are in zero g
- questions that really need to be answered in orbit as we can only simulate it in a limited and rather uncertain way on the Earth
Then as well as that they need shielding from cosmic radiation, and from solar storms. For cosmic radiation - then if they have lots of water they can use that for at least a two year stay it might be enough. For solar storms, probably need a more highly insulated refuge they can retreat to during a major storm. The ISS doesn't need this because it is protected from the worst effects of solar storms by the Earth's magnetic field.
Then - it would probably have a lifeboat spacecraft permanently attached just as for the ISS. But you'd only be able to get back to Earth every two years at the appropriate launch window. So that's a major difference + the communications.
Would also need to work out better communications with Earth. Probably laser communication? Because you'd need a lot of bandwidth. Probably need to build new radio telescopes on Earth to receive the signals also I'd imagine.
And - the other big difference - your main objective would be exploring Mars, not just studying effects of zero g.
So - you'd have telepresence equipment as standard. I think myself probably have omnidirectional treadmills and VR glasses and haptic feedback gloves. And loads of workstations to control all the rovers and other instruments on Mars. And - once scientists know that their spacecraft can be controlled from Mars orbit, then I'm sure every mission to Mars would be designed for telepresence operation. So that is what the crew would probably spend most of their time doing, unlike the ISS.
I see this as fairly far into the future. At a minimum, you have to have a few years experience of all the relevant technologies in the Earth Moon system where you can have a lifeboat to return you to Earth within a day or two, before it is responsible to risk humans with the same technology to Mars.
Reason being that it would take up to two years and six months to get back in case of an emergency, would take same length of time also to get emergency replacements and other emergency supplies to the crew in Mars orbit. Also you have up to 40 minutes delay between asking a question and getting a reply when you try to get support for maybe some intricate technical issue that you have to solve quickly or you are dead.
All this makes any kind of human occupied space station in Mars orbit many times harder than the ISS, so - I think myself we need to take this one step at a time and sort all these things out in the Earth / Moon system first.
All the same, it is feasible, I think we can do it some time. And far far more feasible and far safer, and also acceptable according to planetary protection than ideas to send humans to the surface of Mars.
About the Author
Robert Walker
Writer of articles on Mars and Space issues - Software Developer of Tune Smithy, Bounce Metronome etc.Studied at Wolfson College, Oxford
Lives in Isle of Mull
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