Mars Polar Lander Launch Sequence Diagrams
Mars Polar Lander Boost Profile
Liftoff will take place from Space Launch Complex 17B at Cape Canaveral Air Station, Florida. Sixty-six seconds after liftoff, two of the four solid rocket strap-ons will be discarded. The remaining strap-on boosters will be jettisoned one second later, while the first stage continues to burn. About 4 minutes, 24 seconds after liftoff, the first stage will stop firing and be discarded eight seconds later. About five seconds later, the second stage engine ignites. The fairing or nose-cone enclosure of the launch vehicle will be discarded 4 minutes, 42 seconds after liftoff. The second-stage burn ends about 11 minutes, 22 seconds after liftoff.
Mars Polar Lander Injection Phase
At this point, the vehicle will be in a low-Earth orbit at an altitude of 191 kilometers (119 miles). Depending on the actual launch date, the vehicle will then coast for 23 to 26 minutes. Once the vehicle is at the correct point in its orbit, the second stage will be restarted for a brief second burn.
Orbit Trace - 93 Deg Flight Azimuth
January 3, 1999
Small rockets will then be fired to spin up the third stage on a turntable attached to the second stage. The third stage will separate and ignite its motor, sending the spacecraft out of Earth orbit. A nutation control system (a thruster on an arm mounted on the side of the third stage) will be used to maintain stability during this 88-second burn. After that, the spinning upper stage and the attached Mars Polar Lander must be despun so that the spacecraft can be separated and acquire its proper cruise orientation. This is accomplished by a set of weights that are reeled out from the side of the spinning vehicle on flexible lines, much as spinning ice skaters slow themselves by extending their arms. Approximately 46 to 49 minutes after liftoff, Mars Polar Lander will separate from the Delta's third stage. Any remaining spin will be removed using the lander's onboard thrusters.
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