NASA's Phoenix spacecraft landed in the northern polar region of Mars on May 25 to begin a three-month probe of a site likely to have frozen water within reach of the lander's robotic arm.
Radio signals received at 7:53:44 Eastern Time confirmed that the Phoenix Mars Lander had survived its difficult final descent and touchdown 15 minutes earlier. The signals took that long to travel from Mars to Earth at the speed of light.
Among those in NASA's Jet Propulsion Laboratory, Pasadena, California, was US space agency's administrator Michael Griffin, who noted that this was the first successful Mars landing without airbags since Viking 2 in 1976.
"For the first time in 32 years, and only the third time in history, a JPL team has carried out a soft landing on Mars," Griffin said, adding, "I couldn't be happier to be here to witness this incredible achievement."
During its 422-million-mile flight from Earth to Mars after launching on August 4, 2007, Phoenix relied on electricity from solar panels during the spacecraft's cruise stage. The cruise stage
was jettisoned seven minutes before the lander, encased in a protective shell, entered the Martian atmosphere. Batteries provide electricity until the lander's own pair of solar arrays spread open.
"We have passed the hardest part and we are breathing again, but we still need to see that Phoenix has opened its solar arrays and begun generating power," said JPL's Barry Goldstein, the Phoenix project manager.
Phoenix uses hardware from a spacecraft built for a 2001 launch that was cancelled in response to the loss of a similar Mars spacecraft during a 1999 landing attempt. Researchers, who proposed the Phoenix mission in 2002, saw the unused spacecraft as a resource for pursuing a new science opportunity.
Earlier in 2002, Mars Odyssey discovered that plentiful water ice lies just beneath the surface throughout much of high-latitude Mars. NASA chose the Phoenix proposal over 24 other proposals to become the first endeavour in the Mars Scout program of competitively selected missions.
Image: Maria Schellpfeffer, Sequence System Engineer, monitoring the Landing Orientation on the screen in the NASA/JPL mission control.
Photograph: Lawrence K Ho-Pool/Getty Images