Washington, May 24 : NASA's Phoenix Mars Lander, that is all set to land on the surface of the Red Planet on May 25, will face a harrowing seven minutes during touchdown, in which it would have to complete a challenging sequence of events to land safely.
According to a report in National Geographic News, the probe is slated to touch down near the red planet's north pole.
NASA scientists have described the touchdown as "seven minutes of terror", which could make or break the 420 million dollar mission.
"Approximately 14 minutes before touchdown, the vehicle separates from its cruise stage," said Barry Goldstein, Phoenix project manager at the Jet Propulsion Laboratory in California. "At this point, we lose communication from the vehicle," he added.
Once the craft reaches Mars's atmosphere, the next critical seven minutes make up what's known as the Entry, Descent, and Landing (EDL) phase.
Screaming down at about 12,600 miles (20,270 kilometers) an hour, the craft must open a parachute to slow itself for a three-minute glide to the surface about 70 miles (113 kilometers) below.
The craft's landing sequence then includes steps such as jettisoning its heat shield, extending its legs, and firing its landing thrusters.
"There are 26 pyrotechnic events, and each of those have to work perfectly for this to go as planned," said Goldstein. "Getting EDL communication (at touchdown)-that'll be the three seconds that I am really biting my nails over," he added.
The landing site, informally dubbed Green Valley, sits in a region of permafrost on Mars's northern plains. The relatively shallow valley, which contains some of the highest concentrations of ice outside of the polar cap, is about 700 feet (213 meters) deep and stretches for 40 miles (64 kilometers).
A crater near the valley means that an impact pushed away most large rocks and spread out a soft cushion of fine particles 5 to 10 inches (13 to 25 centimeters) deep on top of the hard icy soil.
"But this is no trip to grandma's for the weekend," warned Ed Weiler, NASA's associate administrator for the Science Mission Directorate. "Mars has been known to cause trouble, and I'll be worried until I hear the signal a few seconds after landing," he added.
But, according to team leaders from the University of Arizona, the NASA Jet Propulsion Laboratory and Lockheed Martin, the spacecraft is healthy, right on target, and even predicted to have good landing weather.
"All systems are nominal and stable," said Ed Sedivy, Phoenix spacecraft program manager for Lockheed Martin Space Systems, of Denver, which built the spacecraft. "We have plenty of propellant, the temperatures look good and the batteries are fully charged," he added.