I think we should go the, “The moon is a harsh mistress,” route and set up mining and manufacturing plants on the moon itself. Saves the cost and environmental impact of having to lift everything up from the surface. Minus the worker exploitation, of course.
Idk if anyone has actually crunched the numbers on the horizontal launch system the book uses, but in a nutshell they basically shaved the top off of some mountains on the equator and made a gigantic rail gun to get ships closer to escape velocity before boosters are needed.
Assuming you want a semimajor axis of 1100 miles, just a few miles above the surface, you need to accelerate to about 1600 m/s
Let’s say our astronauts are extremely well trained, and can handle 10 gs. The Railgun would need to accelerate them to 1600 m/s. Divided by 100 m/s^2 means they’ll be accelerating for about 16 seconds. That’s as much as I can math on my own, so I’m gonna defer to this calculator, which says you need to accelerate over a distance of about 13 kilometers. That’s a big railgun.
If they only used it for materials and unmanned satellites, then a more reasonably sized 1 km railgun would accelerate the payload at around 130 gs. An even more reasonable 100 meter long railgun (just 5 times longer than real life railguns) would reach about 1300 gs, which isn’t bonkers high if the satellite is built for it, but would change any living thing trying to hitch a ride from biology to physics
ETA: Escape velocity is √2 times circular orbit velocity, for math and science reasons. This railgun would need to accelerate payloads to around 2250 m/2. The human railgun would need to be 25 kilometers long, and the astronauts would be experiencing 10 gs for about 22 seconds. Couldn’t pay me enough.
Who am I kidding, I’d literally die for a chance to visit the moon
I think we should go the, “The moon is a harsh mistress,” route and set up mining and manufacturing plants on the moon itself. Saves the cost and environmental impact of having to lift everything up from the surface. Minus the worker exploitation, of course.
Idk if anyone has actually crunched the numbers on the horizontal launch system the book uses, but in a nutshell they basically shaved the top off of some mountains on the equator and made a gigantic rail gun to get ships closer to escape velocity before boosters are needed.
I’m gonna try to crunch some numbers
Assuming you want a semimajor axis of 1100 miles, just a few miles above the surface, you need to accelerate to about 1600 m/s
Let’s say our astronauts are extremely well trained, and can handle 10 gs. The Railgun would need to accelerate them to 1600 m/s. Divided by 100 m/s^2 means they’ll be accelerating for about 16 seconds. That’s as much as I can math on my own, so I’m gonna defer to this calculator, which says you need to accelerate over a distance of about 13 kilometers. That’s a big railgun.
If they only used it for materials and unmanned satellites, then a more reasonably sized 1 km railgun would accelerate the payload at around 130 gs. An even more reasonable 100 meter long railgun (just 5 times longer than real life railguns) would reach about 1300 gs, which isn’t bonkers high if the satellite is built for it, but would change any living thing trying to hitch a ride from biology to physics
ETA: Escape velocity is √2 times circular orbit velocity, for math and science reasons. This railgun would need to accelerate payloads to around 2250 m/2. The human railgun would need to be 25 kilometers long, and the astronauts would be experiencing 10 gs for about 22 seconds. Couldn’t pay me enough.
Who am I kidding, I’d literally die for a chance to visit the moon
A skyhook would be a lot easier to implement on the moon than Earth (no atmosphere and 1/6 gravity).