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Space Shuttle: Difference between revisions
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→RCS DAP schemes
| Line 205: | Line 205: | ||
; RCS ROT ENTRY | ; RCS ROT ENTRY | ||
: A 'stick controls rates' DAP designed for entering the atmosphere which enforces a 'no sideslip' attitude in which the nose module is not used. This has very strict deadbands and aggressive gains to combat the yaw instability of the Shuttle upon entry, significant mode mixing and is very propellant-consuming. Do not use in orbit and only activate at the entry interface once the shuttle has the correct attitude! | : A 'stick controls rates' DAP designed for entering the atmosphere which enforces a 'no sideslip' attitude in which the nose module is not used. This has very strict deadbands and aggressive gains to combat the yaw instability of the Shuttle upon entry, significant mode mixing and is very propellant-consuming. Do not use in orbit and only activate at the entry interface once the shuttle has the correct attitude! During entry, the DAP will gradually transfer control to the 'Aerodynamical' DAP - at qbar of 10 lb/sqft the roll axis, at 40 lb/sqft the pitch axis and at around Mach 3.5 the yaw axis. | ||
; Aerojet | |||
: The Aerojet DAP is close to the real entry DAP used by the Shuttle. Its RCS part works similar to RCS ROT ENTRY, but control is not transferred to to the Aerodynamical DAP but to the atmosphere part of Aerojet (see below) which employs the same rate control routines as the RCS part. The scheme also supports an automatic AoA control scheme in which the pilot only has to manage the roll axis during entry, which makes this the most easy to fly DAP for entry and atmospheric flight. | |||
; RCS translation | ; RCS translation | ||
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; RCS TRANS LOW-Z ATT HLD | ; RCS TRANS LOW-Z ATT HLD | ||
: As in the previous mode, only an attitude hold is commanded in addition. For weak thrust this works well, for strong thrust the controller is, without using upward-pointing thrusters, unable to completely control the pitching motion. | : As in the previous mode, only an attitude hold is commanded in addition. For weak thrust this works well, for strong thrust the controller is, without using upward-pointing thrusters, unable to completely control the pitching motion. | ||