NASA’s Phoenix Mars lander made a planned trajectory correction maneuver (TCM) on April 10, burning its thrusters for 35 seconds. If the analysis shows that this TCM was spot on, a TCM 4 won’t be needed, Lockheed Martin space central officials have told me.

Lockheed Martin Space Systems is the aerospace firm that built the outward-bound Mars craft that’s headed for a red planet landing next month, on May 25th. The University of Arizona’s Lunar and Planetary Laboratory heads the Phoenix scientific mission, a hub for researchers around the world teaming together to explore the arctic plains of Mars.

Meanwhile, the landing spot for Phoenix in the martian arctic was okayed on March 27th at NASA HQ in Washington, D.C.

The Phoenix landing locale: polygonal plains in “Green Valley” - a site that offers smooth plains with a few scattered rocks, explained Ray Arvidson at Washington University in Saint Louis. He’s a co-investigator of the robotic arm on the Phoenix mission and a leading Mars scientist.

Arvidson told me that the plains are covered with polygons a few meters across and perhaps roughly 10 centimeters high. Dirty water ice is expected just beneath the surface, perhaps with some depth variations from the polygon centers to the troughs that ring the polygons.

Picking that landing zone has been a team effort, Arvidson added, making use of assets not only on NASA’s Mars Reconnaissance Orbiter (MRO) and the Odyssey orbiter, but also thanks to the European Space Agency’s Mars Express, also circling the red planet.

Thanks to the super-powerful zoom camera on MRO as it sweeps over Mars landscape, there’s been an ability to characterize and map the widths and heights of over 5 million rocks, Arvidson said.