CAPE CANAVERAL, Fla. — The May 26 landing of NASA’s Space Shuttle Atlantis may have capped a successful mission slated to be the ship’s last trek to space, but the orbiter’s immediate future is not set in stone.

Debate is under way on whether the shuttle should get one more flight or be sent straight to a museum.

As Atlantis’ most recent mission demonstrated, the orbiter is in good shape, NASA shuttle officials said May 26 just after the shuttle landed here at the agency’s Kennedy Space Center in Florida.

“Not only is this mission fantastic, but the entire life of Atlantis, the folks who built it, all the missions it’s flown over its career have been just amazing,” shuttle launch integration manager Mike Moses said.

The shuttle finished a 12-day mission to the international space station to deliver a new Russian room and outfit the station with spare parts for the era after NASA’s three-orbiter space shuttle fleet retires. Two more shuttle missions are planned — one each for Atlantis’ sister ships Discovery and Endeavour.

Whether or not the STS-132 mission will be the orbiter’s last spaceflight has not been decided.

After its landing, Atlantis was to be processed and refurbished just in case it has to fly again.

The orbiter is on call to serve as the emergency rescue ship in case of a serious problem with NASA’s final planned shuttle flight, the STS-134 mission of Endeavour slated for no earlier than late November. If something goes awry on that flight, Atlantis could be readied to retrieve Endeavour’s astronauts from the station and return them back to Earth.

However, NASA and lawmakers are also considering whether to shift this “launch on need” mission to a full-fledged final flight.

The hardware, including an expendable external fuel tank, is in place to fly one more |mission.

But that plan would require more funding to retain shuttle workers for longer than currently planned.

Within hours of Atlantis’ May 26 landing, Sen. Bill Nelson (D-Fla.) wrote President Barack Obama to say he was drafting legislation that would authorize NASA to fly the orbiter one more time on a logistic mission targeted for the summer of 2011.

“As you known, Space Shuttle Atlantis will be prepared as a ‘launch on need’ rescue mission supporting the last scheduled flight of the space shuttle (STS-134) in [fiscal year] 2011,” Nelson wrote the president. “If a rescue mission for STS-134 is not flown, it could be used instead for an additional shuttle mission.”

It costs NASA about $200 million a month to keep its space shuttle program running, program managers have said.

One more mission, which NASA would likely launch with a crew of four in June 2011, would allow the agency to stock up on more supplies for the space station since the outpost is slated to continue running through at least 2020.

Beyond the shuttle era, the station will be serviced by manned Russian Soyuz vehicles and unmanned Russian, Japanese, European and American commercial cargo-carrying spacecraft.

Eventually, Obama and NASA hope private companies can build spaceships to ferry astronauts to the orbiting laboratory.

In the meantime, NASA says simply doesn’t have the funds to continue flying the space shuttle and work on developing next-generation rockets and vehicles at the same time.

“I think we’d all love to have kept flying shuttle while we set up the new system. … We just don’t have the budget to do that,” Moses said.

Yet just because the shuttles are headed for retirement does not mean they are not in good health and capable of flying at least one more flight, he said.

“It’s true they are 30 years old but they are not old at all,” Moses said. “They’re in fantastic shape, they fly perfectly and they do exactly what we mean them to.”