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I'm continually unsold on this. Mars is far away, inhospitable, and feels like a run-before-we-walk kind of scenario to me. Merely sending humans to Mars seems

I'm continually unsold on this. Mars is far away, inhospitable, and feels like a run-before-we-walk kind of scenario to me. Merely sending humans to Mars seems like a huge task, let alone keeping them alive there. I've felt for a while that a more practical path would be along the lines of: - Asteroid capture around Earth to develop material processing/construction in space (seems way cheaper than launching ships and resources into orbit, makes space station construction practical?) - Robotic moon base with electromagnetic launcher (cheaply/easily launch resources from the moon, provide practical, closer, safer experience in constructing human habitation away from Earth?) - Mars/Venus. Am I missing something here? Can SpaceX really make launches cheap enough that the benefits of construction in orbit aren't worth it? Is trying to move a biosphere to another planet easy enough with no prior experience?

placeybordeaux 9y ago
I agree that asteroid capture and in space refining/construction seems like the way to go. Once you show that you can make a profit in space other than pointing satellites at the earth you grow the # of people that are interested in participating by a huge amount.
felippee 9y ago
As with all complex matters there are numerous considerations and issues with all of these. Moon is close, we've already been there, escape velocity is low but there appears to be very little water, not very accessible at least. The day/nigh cycle is 28 days long, so there are issues with overheating during the "day" and lack of power during the "night". Solar radiation induces static charge on dust, which makes it go everywhere, particularly difficult condition to run mechanical devices for long periods of time. That said an air-sealed cavern on the Moon could be a great intermediate solution for making humans interplanetary. Electromagnetic launcher could also make our interplanetary ambitions more sustainable. Mars on the other hand has an atmosphere (faint but still), better day/night cycle, more accessible water and carbon dioxide - allowing to manufacture rocket fuel and many chemicals needed for agriculture. Ultimately it seems better then the Moon in many respects, but it is very far away. In case of emergency there is very little that can be done to evacuate, transporting anything there will be more expensive (though not that much more expensive than the moon actually). There is the danger of irradiating astronauts during the trip, so crew missions should take faster transfer windows and trade more fuel for speed. Cargo missions could take longer, with better fuel efficiency. Asteroids would be great but they are hard to work with because of the very low gravity (and electrostatic dust as on the Moon). Capturing one, though perhaps theoretically possible, would require enormous amount of force to change the orbit in any meaningful way. Perhaps detonating a hydrogen bomb near one could provide enough thrust, but likely not enough precision (we would not want such asteroid to accidentally hit the Earth). It would take many years to tow one any close to Earth with regular propulsion, so that is probably out of the question for now.
vtange 9y ago
It's funny that with all this talk recently about the rise of AI and robots, we continue to just assume that space exploration and colonization has to be done with human beings.. As if we've already exhausted the most robots could do with rovers and satellites. From a economic and safety perspective, it would seem far more practical to establish a foothold in non-Earth environments with robots that do the initial habitat construction for humans. I fear we are hand-waving much of the risk the first batch of humans we send to Mars have to shoulder - think the Roanoke Colony of the 16th century
- nojvek 9y ago
  This. Humans are a terrible space faring species. I'm sure in a 100 years we'll figure out how to upload our consciousness into robots and build better space faring bodies. I always think about Von Neumann probes. May be in a 100 years we'll figure out how to make them and we'll colonize the entire galaxy. But first we need to figure out how to get to space in frequent reliable cheap trips.
  - vtange 9y ago
    I kinda blame it on our sci-fi fiction: so far we cannot imagine a space adventure where there are no humans at the frontier. Even the most recent space-themed games and movies fall to this trope. It's almost an ego sort of thing - the main characters have to be human, which comes with all the drama of first-alien-contact, life support, etc. With robots, all that risk is mitigated since there's no risk of loss of life. At the worst we have our bots self-destruct or something.
extrapickles 9y ago
While Venus can support cloud city type colonies, what makes it hard is that you will have to bring them with you, or build them from asteroids along the way. Since Mars has an atmosphere, you can use it to get the delta-v costs to be in the ball-park of landing on the moon. If the numbers SpaceX posted for going to Mars are in the right ballpark, it looks like bypassing construction in orbit is the fastest way to backup humanity. Long term it might be more expensive to do it that way, but it would extend the timeline by decades. Another advantage of doing Mars first is that anyone wanting to do orbital construction will be able to sell their goods to colonists which need lower tech items than the advanced stuff like semiconductors you need for making satellites. This should help bootstrap the industry as making simple, heavy goods (eg: shovels) is easier than trying to make more complex items.
gehwartzen 9y ago
Beyond the most efficient way of sending stuff to Mars I don't think it makes sense to send humans right away. In a decade, the earliest timeframe Musk envisions, robotics, AI, battery/solar technology will have likely advances to the point that it makes much more sense to send robots. Let them explore and build bases for a while and then send humans a few decades later.

placeybordeaux 9y ago

I agree that asteroid capture and in space refining/construction seems like the way to go. Once you show that you can make a profit in space other than pointing satellites at the earth you grow the # of people that are interested in participating by a huge amount.

felippee 9y ago

As with all complex matters there are numerous considerations and issues with all of these. Moon is close, we've already been there, escape velocity is low but there appears to be very little water, not very accessible at least. The day/nigh cycle is 28 days long, so there are issues with overheating during the "day" and lack of power during the "night". Solar radiation induces static charge on dust, which makes it go everywhere, particularly difficult condition to run mechanical devices for long periods of time. That said an air-sealed cavern on the Moon could be a great intermediate solution for making humans interplanetary. Electromagnetic launcher could also make our interplanetary ambitions more sustainable. Mars on the other hand has an atmosphere (faint but still), better day/night cycle, more accessible water and carbon dioxide - allowing to manufacture rocket fuel and many chemicals needed for agriculture. Ultimately it seems better then the Moon in many respects, but it is very far away. In case of emergency there is very little that can be done to evacuate, transporting anything there will be more expensive (though not that much more expensive than the moon actually). There is the danger of irradiating astronauts during the trip, so crew missions should take faster transfer windows and trade more fuel for speed. Cargo missions could take longer, with better fuel efficiency. Asteroids would be great but they are hard to work with because of the very low gravity (and electrostatic dust as on the Moon). Capturing one, though perhaps theoretically possible, would require enormous amount of force to change the orbit in any meaningful way. Perhaps detonating a hydrogen bomb near one could provide enough thrust, but likely not enough precision (we would not want such asteroid to accidentally hit the Earth). It would take many years to tow one any close to Earth with regular propulsion, so that is probably out of the question for now.

vtange 9y ago

It's funny that with all this talk recently about the rise of AI and robots, we continue to just assume that space exploration and colonization has to be done with human beings.. As if we've already exhausted the most robots could do with rovers and satellites. From a economic and safety perspective, it would seem far more practical to establish a foothold in non-Earth environments with robots that do the initial habitat construction for humans. I fear we are hand-waving much of the risk the first batch of humans we send to Mars have to shoulder - think the Roanoke Colony of the 16th century

nojvek 9y ago
This. Humans are a terrible space faring species. I'm sure in a 100 years we'll figure out how to upload our consciousness into robots and build better space faring bodies. I always think about Von Neumann probes. May be in a 100 years we'll figure out how to make them and we'll colonize the entire galaxy. But first we need to figure out how to get to space in frequent reliable cheap trips.
- vtange 9y ago
  I kinda blame it on our sci-fi fiction: so far we cannot imagine a space adventure where there are no humans at the frontier. Even the most recent space-themed games and movies fall to this trope. It's almost an ego sort of thing - the main characters have to be human, which comes with all the drama of first-alien-contact, life support, etc. With robots, all that risk is mitigated since there's no risk of loss of life. At the worst we have our bots self-destruct or something.

extrapickles 9y ago

While Venus can support cloud city type colonies, what makes it hard is that you will have to bring them with you, or build them from asteroids along the way. Since Mars has an atmosphere, you can use it to get the delta-v costs to be in the ball-park of landing on the moon. If the numbers SpaceX posted for going to Mars are in the right ballpark, it looks like bypassing construction in orbit is the fastest way to backup humanity. Long term it might be more expensive to do it that way, but it would extend the timeline by decades. Another advantage of doing Mars first is that anyone wanting to do orbital construction will be able to sell their goods to colonists which need lower tech items than the advanced stuff like semiconductors you need for making satellites. This should help bootstrap the industry as making simple, heavy goods (eg: shovels) is easier than trying to make more complex items.

gehwartzen 9y ago

Beyond the most efficient way of sending stuff to Mars I don't think it makes sense to send humans right away. In a decade, the earliest timeframe Musk envisions, robotics, AI, battery/solar technology will have likely advances to the point that it makes much more sense to send robots. Let them explore and build bases for a while and then send humans a few decades later.