Astronauts from the shuttle Atlantis and International Space Station gather Friday to talk with President Obama. Mike Fossum, Chris Ferguson, Andre Borisenko and Ron Garan are pictured in the front row, left to right. Sandra Magnus, left, and Alexander Samokutyaev are pictured in the middle. Doug Hurley, Rex Walheim, Sergey Volkov and Satoshi Furukawa are pictured in the top row, left to right. Photo credit/NASA TV

President Obama commended NASA’s shuttle program in a call to the Atlantis astronauts on Friday in which he also re-stated his call for the space agency to develop the technologies for bold new missions of human exploration.

An expedition to Mars is NASA’s ultimate destination, the nation’s commander-in-chief told Atlantis commander Chris Ferguson, pilot Doug Hurley and mission specialists Sandra Magnus and Rex Walheim.

“I just wanted to say how proud I am of all of you,” Obama said in the nine minute telephone call from the White House. “Congratulations to NASA, to all of our international partners and all of the personnel — past and present — who have spent countless hours and untold efforts in making the space shuttle and the International Space Station a unique part of our history. Accept my gratitude on this tremendous accomplishment.”

The Atlantis crew is in the midst of the final flight of NASA’s 30-year shuttle program, a 13-day voyage to fortify the orbiting science laboratory for six person crew operations through 2012. The food, spare parts and other equipment the shuttle astronauts are leaving behind is intended to transition the station to U. S. commercial re-supply services.

“While this mission marks the final flight of the space shuttle program, it also ushers in an exciting new era to push the frontiers of space exploration and human space flight,” Obama told the Atlantis fliers.

President Obama watches July 8 Lift Off of Atlantis from the Oval Office. Photo Credit/White House photo

 “Crew members like you will continue to operate the International Space Station in coming years and seek to use it to advance scientific research and technology development,” Obama said. “I’ve tasked NASA with an ambitious new mission to develop the systems and kinds of space technologies that will be necessary to conduct exploration beyond the Earth and ultimately sending humans to Mars, Obviously no small feat, I know we will be up to the task.”

The White House and Congress have agreed to operate the U. S.-led, 15 nation space station project through at least 2020.

The station’s assembly and outfitting began in 1998, and the orbital outpost has been continuously staffed by U. S., Russian, European, Japanese and Canadian astronauts since late 2000.

Last year, Obama directed NASA to prepare for a human mission to an asteroid by 2025, a destination paving the way for missions to the Red Planet a decade or so later.

Atlantis lifted off on July 8 and docked with the station two days later.

Ferguson, Hurley, Magnus and Walheim are scheduled to depart the station aboard Atlantis on Tuesday and descend to Earth early Thursday.

The first U. S. commercial cargo missions to the station are likely by early 2012, and possibly late this year.

Russia will transport NASA astronauts to and from the station until U. S. commercial crew transportation services become available, possibly in the 2015-16 timeframe.

The White House and Congress are debating plans for NASA’s Multi-Purpose Crew Vehicle and the Space Launch System, a crew capsule and new heavy lift rocket tailored for missions to a range of deep space destinations.  Current legislation calls for both the MPCV and new rocket to be ready for operations by the end of 2016.