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As it turned out, the ship did not exactly thread this navigational needle, slipping into the atmosphere just before 10 a.m. Pacific time at an incline of 13.9[degrees]. In the cluster of cubicles that serve as J.P.L.'s modest mission control, the engineers seated at consoles leaned forward, looking for the telemetry numbers that would indicate that the ship was indeed decelerating as it should. Support engineers stood behind them, squinting at the screens. At his console, chief engineer Rob Manning scanned the numbers flowing back from space. "Spacecraft is now slowing down very rapidly," he said reassuringly.
When Pathfinder was closer than seven miles above the Martian hardscrabble and two minutes from landing, a 40-ft. parachute opened. Less than 1,000 ft. up, a swaddling of shock-absorbing airbags inflated. Immediately after that, a cluster of retrorockets fired for a quick 2-sec. burst, applying a final brake. The almost comically balloonlike ship then struck the surface at about 22 m.p.h., bounced as high as 50 ft. and finally came to rest somewhere in the 4.6 billion-year-old dust.
At first the J.P.L. controllers had no indication that the ship had survived this inelegant landing--and the engineers didn't expect one. The only antenna capable of transmitting through the ship's cocoon of balloons was a single, whiplike stalk protruding from between two of the bags. If Pathfinder landed upside down, however, the antenna would be crushed against the ground. It would then be at least two hours before the bags could deflate and one of three metal petals that make up the sides of the ship could open, turning the entire structure upright. Only then could a more powerful transmitter inside send out a brighter radio beacon.
As it turned out, Pathfinder rolled to a stop in precisely the right position, with its base down and its antenna up. Inside mission control, Manning squinted at his monitor and saw that contact with the ship had been maintained. "A signal is barely visible," he announced with a grin. The controllers burst into cheers.
Preliminary readings from the ship indicated that landing conditions were well within what the engineers had expected. Pathfinder was tilted at an angle of less than 3[degrees], plenty flat enough to allow the rover to disembark. The solar arrays were being bathed by sun and were producing all the power the spacecraft needed. That same sun, however, was providing little heat: the temperature at Ares Vallis was a crisp -64[degrees]F. But Pathfinder, built to function in that kind of killing cold, seemed unaffected. "I'm ecstatic," said flight systems manager Brian Muirhead as the stream of healthy signals poured into J.P.L. "This is way beyond our expectations."
Whether the ship would continue to exceed expectations would not be known until later in the day, however, when the cameras on the lander were at last brought online. Before that could happen, the airbags had to deflate completely, and actuator motors, powerful enough to pull a small boulder, had to draw them under the ship. Then Pathfinder itself had to open up, exposing the Sojourner rover inside and sending back the first black-and-white pictures.