PASADENA, Calif. – The big day has finally arrived: After 10 months of spaceflight, NASA's Phoenix Mars Lander is headed for its long-awaited attempt to touch down in the arctic region of the red planet later today.

"We've bet the whole farm on this safe landing," said Phoenix principal investigator Peter Smith of the University of Arizona in a Saturday briefing here at NASA's Jet Propulsion Laboratory (JPL). "We can't do our science without the safe landing."

Phoenix is slated to land on the Vastitas Borealis plains of Mars later today, with mission scientists expecting to receive the first signal that Phoenix has landed at 7:53 p.m. EDT (2353 GMT). (The signal should arrive at Earth about 15 minutes after leaving Mars due to the 171 million miles (275 million km) between the red planet and Earth.)

If all goes well, Phoenix will touchdown under its own rockets to mark NASA's first powered landing on Mars since the agency's two Viking probes landed in 1976. The last spacecraft to attempt a powered landing - the ill-fated Mars Polar Lander (MPL) - crashed before reaching the surface of the planet's southern polar region in 1999.

By the time Phoenix arrives at Mars, travelling at 6,100 mph (9,800 kph), the Mars Reconnaissance Orbiter, Mars Odyssey Orbiter and the ESA's Mars Express will be in position to observe its landing attempt and relay information back to Earth.

To make a successful landing, the craft must execute a complicated series of actions in a very short amount of time; it will take just seven terrifying minutes for the spacecraft to plummet through the Martian atmosphere, mission managers have said.

"It's not going to be an easy one," said Phoenix mission manager Joe Guinn of JPL. But he added, "I think we're actually in fairly good shape."

Phoenix should separate from its cruise stage at about 7:39 p.m. EDT (2339 GMT) tonight, after which there will be a three-second communication blackout before the craft's UHF radio antenna is supposed to kick in. Barry Goldstein, Phoenix project manager of JPL, has said that milestone is the one that worries him most. If communications aren't restored between Phoenix and Earth and the lander fails, scientists won't be able to glean any data to tell what went wrong, he added.

The spacecraft is then supposed to turn and enter the atmosphere, its heat shield guarding it from the superhot plasma created by friction as the craft falls. (This plasma could cause another blackout period by interfering with the UHF antenna.) This stage will reduce Phoenix's speed by 90 percent until it's falling at 1.5 times the speed of sound.

Phoenix is then supposed to deploy its orange and white parachute, jettison its heat shield and stick out its landing legs. Shortly after, its radar system should activate, providing the craft with its first measurement of where the ground is.

Once that occurs, Phoenix should separate from its back shell at 7:50:15 p.m. EDT (2350:15 GMT) and fire up its thrusters to further slow its descent and guide it to a three-point landing.

or does this mean, they'll be showing the landing?

Thank you for keeping us updated with the Space News section Waspie Dwarf.

Here is to a good job NASA.I congratulate you on a mission well done !!!!!!!!!!!!!!!!!!!!!.

I think I'll give it three months before I congratulate NASA on a mission well done, but certainly the most difficult and risky part of the mission is out of the way. Now the work starts.

Sorry.Am a bit fussy today.Was actually meant for the entry.But did not want to repeat the early peoples posts

Sorry if I gave the impression that I was criticising you, that wasn't the case at all. I knew what you meant. I was just trying to highlight the fact that the real work starts now.

Sometimes this is not the best form of communication and can lead to misunderstandings.