Flying the Shuttle - Launch
| Note This article refers to the Space Shuttle in the FGAddon repository. |
This mission phase can directly be started using --aircraft=SpaceShuttle-launch on the command line.
What are we trying to do?
The launch phase of the Shuttle lasts from ignition of the main engines till the shuttle reaches orbit. This is a surprisingly short time, all in all just about eight minutes. During this time, an enormous amount of propellant is spent accelerating the orbiter to Mach 26 at an altitude of 150 km. The complete launch stack consists of the orbiter, mounted on the external tank (ET) which supplies propellant for the Space Shuttle Main Engines (SSMEs), assisted by two solid rocket boosters (SRBs).
The first two minutes of the flight pass through the atmosphere, during this time the SRBs provide most of the thrust. The SRBs can not be throttled, once on, they burn till they are spent. At an altitude of about 150.000 ft the SRBs are disconnected and the shuttle accelerates only using the main engines fed from the ET which is disconnected just before reaching orbit.
The tasks are hence
- bring the orbiter safely through the atmosphere
- steer towards a launch course corresponding to an orbit with the desired inclination
- accelerate to orbital speed outside the atmosphere
Some theory
How it feels in FG
The launch dynamics in FG is, if we neglect the noise and the shaking of the real thing (which is described as 'driving down a rough gravel road without any suspension, a shaking so hard the eyes cannot properly focus' as long as the SRBs are burning) probably fairly realistic.
As soon as the throttle is moved to 65%, the main engines ignite. This is the starting signal for SRB ignition, the SRBs will follow three seconds later, and once they burn, there is no going back. The SRBs can not be throttled and will burn till exhausted, and they have enough thrust to lift the stack even if the main engine is switched off.
Directly
