An important initial step in securing an off-world future is starting and scaling manufacturing in space.
Several companies are already working on the problem of mining in space, to capture the rich deposits of gold and other metals embedded in asteroids. But most likely those metals will be brought back to Earth to be worked. We’ll still need to figure out how to process raw materials and build things without the benefit of gravity and, eventually, without bright starlight. Otherwise, any vessel we permanently eject from Earth, no matter how well provisioned, will ultimately break down and kill its inhabitants.
But how to get started? I think we start simply. Do something that draws attention and gets people thinking about doing business from space. Take a straightforward, known manufacturing process, and reproduce it in space.
Like T-shirts. Truck all the fabric, thread, tags, and equipment into orbit, assemble a batch of shirts there, and cart it back down. Label it “Made in Space” and charge hundreds of dollars for it.
Would you buy a shirt simply because it was made in space? I would.