We've learned a lot since the rather naive plans of the 1970s, when space colonization was first proposed by Gerard O'Neill and his students. How are things different now? What's the most important thing we've learned since then?
Hi Geoff. Dani Eder here. I would say the most important thing we have learned is "there are a whole lot of Near Earth Asteroids". In 1980 there were 52 known NEA's ( http://neo.jpl.nasa.gov/stats/ [nasa.gov] ). Today we are rapidly approaching 13,000 at a rate of about 1,500 new ones a year. This has completely changed the accessibility of raw materials. Given that we now have well developed electric propulsion, 90% of NEA's take less fuel to reach than the surface of the Moon.
Even if you want to go to the Moon, the math says to mine asteroids for propellant to get there. Some asteroids are up to 20% water and carbon. This can be reformed to Oxygen and Hydrocarbons, which makes good high-thrust chemical propellant for landers.
Next I would say the advances in computers, automation, robotics, and high bandwidth communication are important. O'Neill assumed 10,000 people in a colony, because that's how many people it would take to build solar power satellites and all of the supporting tasks to keep them alive. Today we can think about automating it or controlling a lot of that from the ground. That means we can bootstrap construction with a small team of actual humans in space (some tasks still have to be hands-on).
Lastly, I would mention that the "O'Neill Cylinder" design, while pretty, is a nightmare from an engineering safety standpoint. One meteorite or out of control cargo ship hitting those giant windows, and all your air leaks out. You want stuff like multi-layered Whipple shields to break up incoming objects, and a layered and compartmentalized pressure hull. If you want natural sunlight, bring it in through protected openings.
I think you have O'Neill's reasoning backwards, though. He didn't say "we need to build solar power satellites, therefore we need a colony of 10,000 people"-- he said "we've shown that there are no showstoppers to building a colony of 10,000 people; what will they do? Here's an idea; they will build solar power satellites."
So, the question now is, if you don't need very many people-- and possibly don't need any people--in space to build solar power satellites, what is the economic base for of
Only through hard work and perseverance can one truly suffer.
We've learned a lot (Score:2)
We've learned a lot since the rather naive plans of the 1970s, when space colonization was first proposed by Gerard O'Neill and his students.
How are things different now? What's the most important thing we've learned since then?
Re:We've learned a lot (Score:3)
Hi Geoff. Dani Eder here. I would say the most important thing we have learned is "there are a whole lot of Near Earth Asteroids". In 1980 there were 52 known NEA's ( http://neo.jpl.nasa.gov/stats/ [nasa.gov] ). Today we are rapidly approaching 13,000 at a rate of about 1,500 new ones a year. This has completely changed the accessibility of raw materials. Given that we now have well developed electric propulsion, 90% of NEA's take less fuel to reach than the surface of the Moon.
Even if you want to go to the Moon, the math says to mine asteroids for propellant to get there. Some asteroids are up to 20% water and carbon. This can be reformed to Oxygen and Hydrocarbons, which makes good high-thrust chemical propellant for landers.
Next I would say the advances in computers, automation, robotics, and high bandwidth communication are important. O'Neill assumed 10,000 people in a colony, because that's how many people it would take to build solar power satellites and all of the supporting tasks to keep them alive. Today we can think about automating it or controlling a lot of that from the ground. That means we can bootstrap construction with a small team of actual humans in space (some tasks still have to be hands-on).
Lastly, I would mention that the "O'Neill Cylinder" design, while pretty, is a nightmare from an engineering safety standpoint. One meteorite or out of control cargo ship hitting those giant windows, and all your air leaks out. You want stuff like multi-layered Whipple shields to break up incoming objects, and a layered and compartmentalized pressure hull. If you want natural sunlight, bring it in through protected openings.
What do we do, if there's nothing to do? (Score:2)
True enough.
I think you have O'Neill's reasoning backwards, though. He didn't say "we need to build solar power satellites, therefore we need a colony of 10,000 people"-- he said "we've shown that there are no showstoppers to building a colony of 10,000 people; what will they do? Here's an idea; they will build solar power satellites."
So, the question now is, if you don't need very many people-- and possibly don't need any people--in space to build solar power satellites, what is the economic base for of