National Geographic News
"Touchdown signal detected."
Riotous applause in Mission Control followed these words from primary commentator Richard Kornfeld today—confirmation that NASA's Phoenix Mars lander successfully touched down near the north pole of Mars.
"Absolutely perfect. It went right down the middle," said Barry Goldstein, Phoenix project manager at the Jet Propulsion Laboratory in Pasadena, moments after the landing.
"It was better than we could have possibly wished for."
At 7:53 p.m. ET Mission Control received the signal that the craft had survived the tricky descent through the red planet's atmosphere dubbed the seven minutes of terror.
During that time the probe had to slow itself from 12,700 miles (20,438 kilometers) an hour to 5 miles (8 kilometers) an hour before gently setting down on Martian permafrost.
Although friction and a parachute helped reduce its speed, Phoenix was designed to separate from the chute at about 0.6 mile (a kilometer) above Mars, relying on pulsing thrusters to smooth its final descent.
Now "we have to make sure the spacecraft is healthy, but by God, it's landed in a place where it's in an almost horizontal position," said Peter Smith, Phoenix principal investigator at the University of Arizona in Tucson.
Data from the craft show that it now sits on Mars with just a quarter of a degree tilt.
Phoenix is now the first probe to reach a Martian pole and the first to successfully land with powered thrusters since the Viking missions in 1976. Both Mars rovers landed using airbags to cushion the blow.
The success is a critical step for possible future human missions to Mars, because people would not survive the high-velocities associated with airbag landings.