Actually, it is a very precise description. A spaceflight simulator is a computer program that allows the reproduction of the movement of one or more objects in free fall around a celestial body within certain predefined limits. The important thing here, though, is “free fall”, because simulators are primarily designed to reproduce how spacecraft are propelled into orbits by either rockets or ion thrusters. When these vehicles lose their propulsion power, they change from being controlled trajectories into being uncontrolled trajectories that only follow the gravity of the celestial bodies where they are placed. This fact can be exploited to try out manoeuvres without having to wait for months or even years before actually carrying them out with expensive real hardware. For instance, if you need 1 kg of propellant to go from Low Earth Orbit (LEO) to an orbit around the Moon, you can either spend a few million dollars and launch it there directly, or you can save some propellants and simulate how your rocket will perform when flying between those two orbits. There is also the option of simply launching a spacecraft to LEO and orbit around our planet without performing any propulsion whatsoever, but this would be very boring, so I’ll skip that one.
The spacecraft’s motion in spaceflight simulators
The spacecraft’s motion in spaceflight simulators is exactly what one would expect if they had already travelled for several days in real life: objects are not accelerated by some magical force while approaching celestial bodies, precise collision detection is used instead so that even minor details are reproduced accurately. Of course, the difference is in how one chooses to fly their spacecraft. In real life, when you are about to reach your destination after a few months of space travel, there are still several options available for choosing where to go next. You can choose how to enter into orbit around your target body, or even perform a landing on it. Spaceflight simulators do not include ground vehicles (although some projects like Orbiter 2010 try to change this), but they allow us to perform almost all orbital manoeuvres, including automatic docking with other spacecraft. This has made them popular people who want to simulate complex missions without having to take too many things into consideration.
Spaceflight simulation keyframing
Spaceflight simulation keyframing 6DoF (Six degrees of freedom) is the most popular method to fly spacecraft in simulators. This term makes reference to how motion along predefined axes is controlled by the user. One X-axis, for example, can be used to control horizontal or roll movements, another one for yaw. Why does this have six letters? Because a six-axis is needed to be able to control something’s position without limitations – three rotations and three translations (movements). However, these six degrees of freedom are not commonly experienced simultaneously because it would put too much stress on our body if we were moving around a virtual cockpit while also having free access to move our arms around.
Instead, what usually happens is that four axes are being controlled by the player through their keyboard