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freerangequark
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When a space shuttle launches, how is simultaneous SRB cutoff assured so as not to create an asymmetrical thrust situation? (assuming that SRB cutoff occurs prior to separation).
Thanks,
FRQ
Thanks,
FRQ
http://en.wikipedia.org/wiki/Space_Shuttle_Solid_Rocket_Booster#PropellantSRB separation is initiated when the three solid rocket motor chamber pressure transducers are processed in the redundancy management middle value select and the head-end chamber pressure of both SRBs is less than or equal to 50 lbf/in² (345 kPa). A backup cue is the time elapsed from booster ignition.
The separation sequence is initiated, commanding the thrust vector control actuators to the null position and putting the main propulsion system into a second-stage configuration (0.8 second from sequence initialization), which ensures the thrust of each SRB is less than 100,000 lbf (445 kN). Orbiter yaw attitude is held for four seconds, and SRB thrust drops to less than 60,000 lbf (267 kN).
http://www.csar.uiuc.edu/F_info/space_shuttle_srb.htmThe SRBs are used as matched pairs and each is made up of four solid rocket motor segments. The pairs are matched by loading each of the four motor segments in pairs from the same batches of propellant ingredients to minimize any thrust imbalance.
The Space Shuttle Solid Rocket Boosters (SRBs) are two large solid-fueled rockets attached to the sides of the Space Shuttle. The cutoff and separation refer to the point in the launch when the SRBs have burned through all of their fuel and are jettisoned from the Shuttle.
The SRBs are jettisoned to reduce the weight and drag on the Space Shuttle, allowing it to reach higher speeds and altitudes. This also allows for a more efficient use of fuel during the rest of the launch.
The SRBs burn for approximately two minutes after launch, providing the majority of the thrust needed to lift the Space Shuttle off the ground. Once they have burned through all of their fuel, they are jettisoned.
Yes, the SRBs are designed to be reusable. They are recovered from the ocean after each launch, refurbished, and then used again on future missions.
After separation, the SRBs continue on a ballistic trajectory until they reach an altitude of approximately 150,000 feet. At this point, parachutes are deployed to slow their descent and they land in the ocean, where they are recovered by ships for refurbishment.