You may not know it, but Jeff Bezos is thinking about building orbiting habitats. Bigelow Aerospace is as well and we suspect Elon Musk has been thinking about it too. The rocket Bezos is working on will run on hydrogen, so it will lauch cleanly and on a fuel that can be readily generated. SpaceX banks on Methane which is a bit dirtier but it also wants to generate it using renewables. Combined with reusability this opens up space a bit like transcontinental flight did with the world.
Gravity is an issue though. Human physiology has evolved to work best a 1 G (Earths gravity). Orbiting in the space station is no pleasure, you return feeling like boneless chicken. Mars is a bit better, but still people are even wondering if there needs to be some kind of system to simulate 1 G (1 G is one Earth Gravity) there. The best option we think is Venus, but that planet is a ‘fixer upper’ you can only habitate when floating in baloons in 73 Celsius acid atmosphere (still completely doable).
But what about those orbits? The Moon orbits Earth, you could orbit the Moon or Mars or any other planet. Then you’d be experiencing zero G so that would suck, but there is a solution already propsed by the imfamous Wernher von Braun (The Nazi loved by the USA Jawhol!).
By rotating a sufficiently large tube around you will generate a force that feels a lot like gravity. Wherner proposed a spaceship where this effect would be generated in a narrow corridor. This was also seen in 2001 A Space Odyssee. That vision was based in part on the enormous cost of bringing mass to orbit. Also we can now almost count on the ability of building from the Moon, from which launching is much easier. We think the orbiting habitats can become very large.
If Earth becomes a hot cauldron due to fossil industry domination remaining unbroken and climate warming in a runaway process (starting as we speak), a good place to be would be in space orbiting around Earth. Using the Skylon planes it would probably be possible to fly in and out of orbit so work on the surface to fix the atmosphere could happen as people found refuge in orbit around Earth and the Moon.
Once you develop a space habitat with a larger diameter, say several hunderd meters, which you rotate at sufficient speed, the centrufigal force will feel a lot like real gravity. Not sure how birds would fare, they would have an amazing experience of floating in the air once they reach the center of the ‘tube’. Not sure how the atmosphere would behave as well, clouds in the center of the ‘tube’ diameter would not rain down!
We know SpaceX is dedicated to reaching Mars ASAP, and that’s certainly smart, but preparing a place to stay closer to Earth may also prove viable and attractive, and require development. And then there’s habitats on Earth, but that’ s for another post..