The video discusses the challenges of space travel and proposes a solution using space infrastructure, specifically a technology known as the Skyhook. The Skyhook is a cable and a weight, known as a tether, that can be placed in space. Spacecraft can use these tethers as ladders to climb to higher altitudes and gain speed. The tether can be made to rotate, which slows down its tip relative to the ground at the bottom and speeds it up at the top, providing a massive boost when released. This concept is similar to a catapult.
The tether would dip to a height of 80 to 150 kilometers due to Earth's atmosphere. Specialized spacecraft would be needed to reach the tether. Catching the tip would be a challenge due to the short time window of 60 to 90 seconds. To make this easier, the tip could have a sort of fishing line a kilometer long with a navigation drone that helps the spacecraft connect.
The Skyhook is a battery of orbital energy. Arriving ships bring humans and materials home to Earth, adding energy to the tether, which it can give to other ships departing into space. This way, the tether doesn’t lose any energy. The more we use it, the cheaper it gets.
A set of tethers, one around Earth and one around Mars, could make trips between the planets fast, straightforward, and low cost compared to rockets. The Earth tether would sit in low Earth orbit to grab people and payloads and fling them off to Mars. The Mars tether catches them and slows them down for a landing on the surface.
The tethers could shorten trips between both planets, from nine months down to five or even three, and reduce the scale of the rockets required by between 84 and 96 percent. Even better, people may be able to travel in relative luxury as we could afford to invest in passenger comfort.
Starting from low Mars orbit, a tether could boost ships to the asteroid belt. The first craft sent to a new asteroid would need rockets to slow down at its destination. Subsequent arrivals might find a tether waiting to catch them and send them back for free. Getting to asteroids cheaply is a major factor in opening up the resources of the solar system.
In the long term, nothing is stopping humanity from constructing a zero-propellent transport network for the terrestrial planets, centered on the Martian moons. Tethers are a comparably cheap and sustainable solution to making space travel affordable and the rest of the solar system accessible for exploitation and exploration.
1. Getting to space is currently challenging, likened to going up a mountain on a unicycle with a backpack full of explosives.
2. A rocket needs to reach a velocity of about 40,000km an hour to escape from Earth.
3. To achieve this speed, rockets are mostly containers for fuel with a tiny tip of payload.
4. This is problematic for space travel to other planets, as a lot of heavy stuff is needed for survival and possibly return.
5. The concept of space infrastructure, such as roads for cars, ports for ships, or rails for trains, has been successful in making it easier to get to places.
6. This same solution can be applied to space travel, making getting into orbit and out to the Moon, Mars, and beyond easier and cheaper.
7. The technology for space infrastructure is a cable and a weight, known as a tether.
8. The concept of the Skyhook involves putting tethers, hundreds or thousands of kilometers long, into space and having spacecraft use them as ladders to climb to higher altitudes and gain speed.
9. The Skyhook works even better if it is made to spin.
10. A rotating tether slows down its tip relative to the ground at the bottom and speeds it up at the top like a catapult.
11. This means that you can transfer energy from the tether and get a massive boost when released, more-or-less for free.
12. Specialized fibers already exist that can survive the extraordinary stresses a Skyhook would be faced with.
13. To protect against cuts and collisions from debris and meteorites, the tether can be threaded into a web of redundant fibers.
14. The Skyhook would pass over the same spot many times a day, allowing small, reusable shuttles to catch up with it.
15. At its lowest point, the tether’s tip is dashing through the atmosphere at around 12,000km/h.
16. Due to Earth's atmosphere, the Skyhook can’t be lowered too much or it will get too hot from air friction.
17. Therefore, the tether will dip to a height of 80 to 150 kilometers and no lower.
18. To match this, specialized spacecraft that can get to the tether are needed.
19. Catching the tip will be a challenge, with only a short time window of 60 to 90 seconds to find a tiny thing in the sky, moving at Mach 12.
20. To make this easier, the tip could have a sort of fishing line a kilometer long with a navigation drone that helps the spacecraft connect.
21. Another challenge is keeping the Skyhook in orbit.
22. As more and more ships latch onto it and pull themselves up, they use up the momentum that keeps it in place.
23. If not addressed, it will slow down and crash into the atmosphere.
24. The Skyhook is a battery of orbital energy, and it’s possible to balance the payloads coming in and being sent off.
25. Arriving ships bringing humans and materials home to Earth add energy to the tether, which it can give to other ships departing into space.
26. The more the tether is used, the cheaper it gets.
27. If energy is still being lost with each boost, it can be recovered with small electric or chemical engines that regularly correct the tether’s position.
28. A set of tethers, one around Earth and one around Mars, could make trips between the planets fast, straightforward, and low cost compared to rockets.
29. The Earth tether would sit in low Earth orbit to grab people and payloads and fling them off to Mars.
30. The Mars tether catches them and slows them down for a landing on the surface.
31. In the opposite direction, the tether could pick up a vehicle traveling through Mars’ thin atmosphere at only about 1,000km/h and fling it back to Earth to be caught and lowered down.
32. The tethers could shorten trips between both planets, from nine months down to five or even three, and reduce the scale of the rockets required by between 84 and 96 percent.
33. Even better, people may be able to travel in relative luxury as we could afford to invest in passenger comfort.
34. Together, t