SpaceCast
Pathfinder Special Reports ....................................... July 4, 1997
Pathfinder: A brief History
WASHINGTON, DC - July 4 9:30am EDT - Today's landing on Mars by the NASA Pathfinder space probe ends a seven month voyage across the dark and cold between worlds begun in a flash of fire and smoke. The Mars Pathfinder spacecraft began the long Mars trek on a chilly night last December 4th when a McDonnell Douglas Delta II rocket booster carrying Pathfinder roared to life and rose atop a tail of flame from Cape Canaveral Air Station in Florida. The rocket's second stage deposited the spacecraft and a third stage into a parking orbit of the Earth. While in Earth orbit, engineers checked out the craft's systems and the health of the lander and rover payload, mounted inside an aeroshell heat shield. When all was confirmed to be ready, the third solid fuel "kick" stage attached to the Mars Pathfinder payload package fired to send the craft out of Earth orbit towards the red planet. This third stage was separated from Pathfinder when it's rocket fuel was expended, and the payload package began its seven month lonely cruise to Mars.When Pathfinder and the Delta stage separated, the craft began spinning at 20 rpm. Computers aboard the spacecraft's cruise stage, a cylinder mounted atop the cone-shaped heat shield, began searching for the ground-based Deep Space Network. This global array of space-facing antenna is the means by which NASA communicates with the Pathfinder. The 34-Meter antenna at the Goldstone Tracking Station acquired the probe soon after it left orbit, and the control center at the Jet Propulsion Laboratory in California began exchanging telemetry and radio signals with the spacecraft. Following Pathfinder's acquisition of the sun, it's spin rate was slowed down to just 2 rpm. As the craft passed beyond the moon, it's on-board star scanner sought its guide star and began the process by which the tiny spaceship, with help from Earth, guided itself some 300 million miles from Earth to Mars.
If all goes as planned today, that trip through space will end at about 1:07pm EDT when Pathfinder's heat shield-encased lander will drop down onto Mars surface. Some three hours later, as Earth rises in the Martian sky, Pathfinder's high-gain antenna will acquire the DSN once again and will, in effect, call home to report: "Dan, I made it!".
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