I think this is a bit like asking - what is best, to travel around the coast, or to cross the Pacific, when so far we have spent most of our time paddling back and forth from an island in the Mississipi.
We just aren't ready to go to Mars, or Venus (which is actually a little closer in terms of delta v - if you want to do an orbital mission or round trip return).
First we have to show we can go back to the Moon. Yes, the US did that in the 1960s. But Russia didn't succeed, though it wanted to, nor did anyone else try.
And the US and Russia currently don't have the capability to go to the Moon.
It's okay to say we know in principle how to do it, but that doesn't mean we can do it. We can't use Apollo technology - because the experts who built it are many of them not around, and anyway it wouldn't be possible to source the parts for it, and the technology would be hugely out of date.
The ISS gives us not much preparation for traveling further afield. Especially, it needs to be reprovisioned from Earth every few months, and keeps going wrong. And all the wastes have to go back to Earth. If the ISS was in Mars orbit, all the astronauts on board would undoubtedly have died many times in the last 15 years.
For long term stay in space then - we must find a way to avoid need to resupply every three months. That's expensive enough for the ISS, will be all the more expensive on the Moon or even more so , far far more expensive on Mars. Okay costs would go down, but still.
Some of the things we need to work on:
Or, we could do some of it in lunar orbit or on the Moon - then - you can get back within a few days.
But an asteroidal retrieval - months away from Earth - that seems overly risky right now. We can use robots to do that.
The other possibility though is neither. Just use robots to do everything. Our rovers on Mars are slow because of low bandwidth - this we can fix.
On the Moon - we can explore it very thoroughly from Earth using robots.
No doubt that it costs far less to use robots to explore than to use humans. And - especially for long duration missions - once we figure out how to let them travel more quickly, with more autonomy - the thing is - a robot, once landed on the Moon or on Mars - it can just sit still there, no supplies except a trickle of power from its solar powers - for days, months, weeks if you like.
With humans you have to keep them supplied with food and for short term missions fine, but long term it will easily become a logistics nightmare, with also loads of complicated parts in their life support system, spacesuits etc to go wrong. Same can happen with a spacecraft / rover - but - if a rover fails after two years out of a possible ten or twenty year mission - well it's achieved its primary objectives, that's fine, sad, but it's done pretty well.
If a human dies just after the end of their primary mission - it's not just "well done, you did your primary mission which is what we care about most of all", it's a huge tragedy.
So - humans - they involve lots more investment, the level of risk you can take can never be as high as for robots - and though they get things done more quickly - not hugely so given the clumsiness of spacesuits and the far higher cost - it is not clear that they actually achieve more, if you compare like for like that is, same level of funding for both.
Probably humans working with robots are best. A partnership where each does what it does well.
E.g. if you need to sit out of doors in a vacuum conditions doing a routine experiment for hours on end that takes a lot of time - or indeed, to just sit somewhere and watch patiently for a rare event - robots hugely better than humans. If the place is not survivable by humans or can be contaminated with Earth life, you have no choice, you have to send robots.
If it is risky - climbing cliffs, going into caves etc - you need robots first. On Earth we can do such things - because it is okay to fall on the Earth, if roped up (in case of cliffs). A similar fall in a spacesuit in vacuum conditions risks killing you. So - unless we get super reliable flawless spacesuits somehow - we have to use robots there, it is surely an unacceptable level of risk to send a human on an expedition if a bad stumble will kill them. The Apollo astronauts did fall over many times - but - there was quite a high level of risk there.
You wouldn't want to risk this every day of your life for weeks and months on end:
Now imagine astronauts in spacesuits trying to climb steep hills, or cliffs, or descending into ravines, exploring caves even huge ones kilometers in diameter which may exist on the Moon - I think they will have faithful telerobots that go with them and scout out the most difficult and dangerous places, and do many of the trickiest things by themselves - the telerobots controlled by other humans back at base, maybe with a level of autonomy as well.
So - well I'd like to see humans in space, and they play a role, but if they are going to play a productive and active role in space exploration, science, etc outside of LEO. I think we first need a sustained program of human factors research.
If not, I think we'd better prepare to keep humans in LEO for the near future plus occasional short duration missions to the Moon, maybe eventually lunar settlement similar to Antarctica, but I think it will be a long time before we really have the confidence to go further afield, with good enough technology to be reasonably safe.
Disclaimer: Expressing a personal point of view here of course.
We just aren't ready to go to Mars, or Venus (which is actually a little closer in terms of delta v - if you want to do an orbital mission or round trip return).
First we have to show we can go back to the Moon. Yes, the US did that in the 1960s. But Russia didn't succeed, though it wanted to, nor did anyone else try.
And the US and Russia currently don't have the capability to go to the Moon.
It's okay to say we know in principle how to do it, but that doesn't mean we can do it. We can't use Apollo technology - because the experts who built it are many of them not around, and anyway it wouldn't be possible to source the parts for it, and the technology would be hugely out of date.
The ISS gives us not much preparation for traveling further afield. Especially, it needs to be reprovisioned from Earth every few months, and keeps going wrong. And all the wastes have to go back to Earth. If the ISS was in Mars orbit, all the astronauts on board would undoubtedly have died many times in the last 15 years.
For long term stay in space then - we must find a way to avoid need to resupply every three months. That's expensive enough for the ISS, will be all the more expensive on the Moon or even more so , far far more expensive on Mars. Okay costs would go down, but still.
Some of the things we need to work on:
- Artificial gravity research. It is absurd that we still have no data at all for human health or spin tolerances in space under artificial gravity. It is all guesswork, and simple experiments, tiny fraction of the cost of the ISS, indeed not even a special mission, you could start by tethering a Soyus TMA to its final stage as a counterweight.
Some data, any data on humans in artificial gravity in space, medical effects on the body, and spin tolerances in the very different conditions in space, and adaptability.
Is it like the nausea you get spinning in a circle on Earth? Or more like seasickness (the vertical not the horizontal canals in the ear are stimulated in space, also the otoliths that sense linear acceleration are not stimulated). Do you get over it, or maybe not feel nauseous at all?
What gravity level is best for human health? Do we need gravity 24/7?
It might be that artificial gravity is impractical and useless. But it might be that it solves all the health problems of zero g. It is potentially such a game changer, we must give it a go if serious about human spaceflight - it makes no sense to design for long term missions in space without getting this data first. - Closed system habitats. We need a purpose built human factors research facility where we try keeping humans alive in space, for instance using algae and plants for oxygen and CO2 scrubbing - actually try them in space. Try spinning them for gravity, slowly even. A hundredth g may be enough for plants to get them to grow adapted enough for normal growth. We need to test things like this. Have a facility devoted to human factors research, where the experimenters can experiment as they do in a lab on the Earth - not have to fit in the human factors experiment into many other duties for running a zero gravity lab, or trying to devise an experiment that will answer all the questions in one go. And to try out new ideas on the job, and to not be afraid to try out things that might not work.
- Solar storm shelters - okay they work on paper. But nobody has yet survived in a solar storm out of the Earth's magnetic field. Before we go further afield we need some experience of this.
- Develop systems that actually work for years on end without resupply from Earth. Again is easy to devise a system that works on paper. But if we could do this, we'd be able to save many billions for the ISS. To go to the Moon and stay there for a year or so at a time, will be very expensive unless we can manage without resupply.
- Experiment in telepresence, try exploring the Moon via telepresence. Humans are far safer in habitats, shielded by a few meters of regolith. They are very vulnerable in spacesuits. Many places we simply can't visit in spacesuits (despite science fiction). Likely to be able to see much better, be more nimble (don't have to use clumsy stiff gloves), haptic feedback better, digitally enhanced vision - if we can get telepresence really working for us, we hardly need to leave our habitat at all, except for fun or exercise. Which then will make lunar / deep space missions far safer
Also telepresence is the only technology that will let humans actually explore places where there is life in the solar system directly, without contaminating it with Earth life.
Or, we could do some of it in lunar orbit or on the Moon - then - you can get back within a few days.
But an asteroidal retrieval - months away from Earth - that seems overly risky right now. We can use robots to do that.
The other possibility though is neither. Just use robots to do everything. Our rovers on Mars are slow because of low bandwidth - this we can fix.
On the Moon - we can explore it very thoroughly from Earth using robots.
No doubt that it costs far less to use robots to explore than to use humans. And - especially for long duration missions - once we figure out how to let them travel more quickly, with more autonomy - the thing is - a robot, once landed on the Moon or on Mars - it can just sit still there, no supplies except a trickle of power from its solar powers - for days, months, weeks if you like.
With humans you have to keep them supplied with food and for short term missions fine, but long term it will easily become a logistics nightmare, with also loads of complicated parts in their life support system, spacesuits etc to go wrong. Same can happen with a spacecraft / rover - but - if a rover fails after two years out of a possible ten or twenty year mission - well it's achieved its primary objectives, that's fine, sad, but it's done pretty well.
If a human dies just after the end of their primary mission - it's not just "well done, you did your primary mission which is what we care about most of all", it's a huge tragedy.
So - humans - they involve lots more investment, the level of risk you can take can never be as high as for robots - and though they get things done more quickly - not hugely so given the clumsiness of spacesuits and the far higher cost - it is not clear that they actually achieve more, if you compare like for like that is, same level of funding for both.
Probably humans working with robots are best. A partnership where each does what it does well.
E.g. if you need to sit out of doors in a vacuum conditions doing a routine experiment for hours on end that takes a lot of time - or indeed, to just sit somewhere and watch patiently for a rare event - robots hugely better than humans. If the place is not survivable by humans or can be contaminated with Earth life, you have no choice, you have to send robots.
If it is risky - climbing cliffs, going into caves etc - you need robots first. On Earth we can do such things - because it is okay to fall on the Earth, if roped up (in case of cliffs). A similar fall in a spacesuit in vacuum conditions risks killing you. So - unless we get super reliable flawless spacesuits somehow - we have to use robots there, it is surely an unacceptable level of risk to send a human on an expedition if a bad stumble will kill them. The Apollo astronauts did fall over many times - but - there was quite a high level of risk there.
You wouldn't want to risk this every day of your life for weeks and months on end:
Now imagine astronauts in spacesuits trying to climb steep hills, or cliffs, or descending into ravines, exploring caves even huge ones kilometers in diameter which may exist on the Moon - I think they will have faithful telerobots that go with them and scout out the most difficult and dangerous places, and do many of the trickiest things by themselves - the telerobots controlled by other humans back at base, maybe with a level of autonomy as well.
So - well I'd like to see humans in space, and they play a role, but if they are going to play a productive and active role in space exploration, science, etc outside of LEO. I think we first need a sustained program of human factors research.
If not, I think we'd better prepare to keep humans in LEO for the near future plus occasional short duration missions to the Moon, maybe eventually lunar settlement similar to Antarctica, but I think it will be a long time before we really have the confidence to go further afield, with good enough technology to be reasonably safe.
Disclaimer: Expressing a personal point of view here of course.
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
4.8m answer views110.3k this month
Top Writer2017, 2016, and 2015
Published WriterHuffPost, Slate, and 4 moreHuffPost, Slate, Forbes, Newsweek, Business Insider, and Science 2.0