Wednesday, May 14, 2008

Hear the one about the Mars lander?

Maybe I live in a cave of sorts, but did you know, as I did not, that there is an important Mars mission unfolding? May 25th, the lander element, dubbed "Phoenix" will be hitting the Martian atmosphere in what the BBC calls a "risky descent":
Scientists are preparing for "seven minutes of terror" as a Nasa spacecraft makes a nail-biting descent to the surface of Mars.

The Phoenix lander will begin its plunge through the Martian atmosphere on 25 May (GMT) as it attempts to land in the planet's polar north.

The craft needs to perform a series of challenging manoeuvres along the way.

It then begins a three-month mission to investigate Mars' geological history and potential habitability.

Water is crucial to the mission's objectives. Not only is it a pre-requisite for biology, but it has shaped the planet's geology and climate over billions of years.

Phoenix will touch down on the northern plains, which hold vast stores of water-ice just below ground.

The lander will use a 2.4m robotic arm to dig through the protective topsoil layer to this water-ice below; a scoop on the arm will lift samples of both soil and ice to the lander's deck for detailed scientific analysis.
But Phoenix must first make the perilous journey to the surface.

The spacecraft will enter the top of the Martian atmosphere at almost 5.7km/s (13,000mph).

Pushing hard against the Martian air, its descent will begin to slow. A parachute will then be deployed to reduce the rate of fall still further. Finally, Phoenix will fire thrusters to bring its velocity down to about 2.4m/s (5.4mph) before its three legs touch the ground.

"We fire 26 pyrotechnic events in the last 14 minutes of the journey. Each of those has to work perfectly for the mission to come off as we planned," said Barry Goldstein, project manager from Nasa's Jet Propulsion Laboratory in Pasadena, US.

The final seven minutes to the ground should prove to be the most dramatic. Confirmation of a successful touchdown could come as early as 0053 BST (1953 EDT).
More on the Phoenix mission here:
"This is not a trip to grandma's house. Putting a spacecraft safely on Mars is hard and risky," said Ed Weiler, associate administrator for NASA's Science Mission Directorate at NASA Headquarters in Washington. "Internationally, fewer than half the attempts have succeeded."
NASA site here.

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