Basics Tutorial Part 2

Introduction

An orbit around a planet like Lave is a fall toward that planet with enough horizontal speed so that the point where you will come down is always beyond the horizon.

When you stand on a planet and you throw a stone in a horizontal direction, it will quite quickly curve toward the surface of the planet and hit the ground. The harder you throw the stone, i.e. the more horizontal speed you give it, the further away the stone will hit the ground. But a planet's surface is curved, so that if the stone goes fast enough, the curve it describes in its fall could match the curve of the surface of the planet. This way it can keep falling without ever hitting the ground. This is called an orbit.

If you are standing on top of a tower when you throw your stone, your stone will travel further before it hits the ground, because the curve of its fall will carry it further. So the higher up something is, the less horizontal speed it needs to achieve an orbit. In fact, if it has too much horizontal speed, it will ascend. Given enough speed, it will break free of the planet's gravity and escape into space. Don't throw stones from towers.

If the planet has an atmosphere, a stone thrown from the ground or a tower will be slowed down by drag so that it wil hit the ground eventually. When you are outside an atmosphere, your stone, or space station, doesn't have this problem, so that it can go indefinitely.

Weightlessness

When you fall unobstructed toward a planet, like when you're orbit, you are weightless. This is why things in orbit, and everybody inside, are weightless, and not because they are merely in space. If Lave Station would stop moving relative to the planet, it would weigh almost exactly as much as it would on Lave's surface, and it would fall toward the planet.

Lave station has the exact horizontal velocity needed to orbit Lave at the altitude where it is. If you leave the station with your Cobra and keep your speed low, relative to Lave Station, you will remain in orbit around the planet together with the station. If your speed gets too high, you will either move to a higher or a lower orbit, depending of whether you are going in the same direction as the station, or the other way. In the first case, your speed relative to Lave Station is added to the station's speed, in the latter case your speed is subtracted from it.

Lessons

1. Lesson 1: getting close to a tonne of rubbish - getting back to the station
2. Lesson 2

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Basic flying tutorial main page - Next: Lesson 1