Launch Period - Archive

The orbiter launch period extends for 21 days, opening on April 7 and closing on April 27. The first 12 days of the launch period from April 7 through 18 make up the primary launch period. If the spacecraft is launched during this time, the nominal science mission can be carried out. The secondary launch period runs from April 19 through 27. Because of higher arrival speeds and longer aerobraking periods, launch during this period could impact the science mission. Arrival dates at Mars vary with launch dates and range from October 24 to 28, 2001.

Daily Windows

Two nearly instantaneous launch opportunities occur each day during the launch period. Each is separated by 30 to 60 minutes depending on the day. On April 7, the first is at 11:02 a.m. EDT and the second is at 11:32 a.m. EDT. The opportunities become earlier each day as the window progresses.

Liftoff

Odyssey will liftoff from Space Launch Complex 17 at Cape Canaveral Air Station, Florida. Sixty-six seconds after launch, the first three solid rocket boosters will be discarded. The second set of three booster will follow one second later. The final three boosters are jettisoned two minutes, 11 seconds after launch. About four minutes, 24 seconds after liftoff, the first stage will stop firing and will be discarded eight seconds later. About five seconds after that, the second-stage engine ignites. The fairing or nose-cone enclosure of the launch vehicle will be discarded four minutes, 41 seconds after launch. The first second-stage burn occurs at ten minutes, 3 seconds after launch.

At this point, the vehicle is in low Earth orbit at an altitude of 189 kilometers (117 miles). Depending on the actual launch day and time, the vehicle will then coast for several minutes. Once it is in the correct point in its orbit, the second stage will be restarted at 24 minutes, 32 seconds after launch.

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 third-stage burn. After that, the spinning upper stage and the attached 2001 Mars Odyssey spacecraft 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. Odyssey will separate from the Delta third stage about 33 minutes after launch. Any remaining spin will be removed using the orbiter's onboard thrusters.

About 36 minutes after launch, the solar array is unfolded. About eight minutes later, it is locked in place. Then the spacecraft turns to its initial communication attitude and the transmitter is turned on. About one hour after launch, the 34-meter-diameter (112 foot) antenna at the Deep Space Network complex near Canberra, Australia will acquire Odyssey's signal.