The answer to cheap and efficient means of space travel could be simpler than one might imagine: All that’s needed is a cable and a weight. A video from YouTuber Kurzgesagt explains their vision on cheap, affordable space travel: They believe that using an extremely long “Tether” (a weight with an attached cable) at safe distances around Earth might turn them into “free” means of propulsion into space.
How it works
The tether would be continuously spinning around Earth, so spaceships could hook onto it and utilize it to be pushed towards the target planet.
However, Kurzgesagt reckons that there could be some issues regarding the project: Smaller spacecrafts that can match the speed of the tethers (about 12,000 km/h) are a requirement. The number is huge, but readers should keep in mind that current spacecrafts require a speed of 45,000 km/h to be able to overcome the pull of our planet’s gravity.
Therefore, if the idea proves plausible and viable, it could be applied to other planets (such as Mars) or small asteroids that contain precious resources. The solution could have an immense impact on space travel: The time required to go to Mars would be reduced from 9 months to as low as 3 months, and this also translates to a reduction of the size of the rockets that are used by more than 80% because they no longer need to carry crazy amounts of fuel.