Flight controllers and forecasters continue to monitor the weather at Kennedy Space Center  and Edwards Air Force Base as Atlantis is expected to land today.

Atlantis’ first landing opportunity is at 9:07 a.m. EST on orbit 202. If controllers elect to take it, Commander Steve Frick will perform the deorbit burn to begin the descent to Kennedy. Orbit 203 provides a second opportunity at 10:42 a.m.

The first opportunity for the California base is on Orbit 204 at 12:12 p.m. The final opportunity, the second at Edwards, is on Orbit 205 at 1:47 p.m.

One orbit takes about 90 minutes, so with each extra orbit needed because of adverse weather, the landing time gets later.

The STS-122 mission was launched on February 7, after it was delayed in December last year due to the problems with an ECO sensor.

Atlantis arrived arrived at the station February 9 , delivering ESA’s Columbus laboratory to the station. The crews installed Columbus February 11 and conducted three spacewalks to prepare Columbus for its scientific work. They also replaced an expended nitrogen tank on the station’s P1 truss.

NASA flight director Bryan Lunney said  the U.S. space agency had received "no pressure" from the military to get Atlantis down. "We're not going to alter any of our (safety) rules," he said. "If the weather is good on Wednesday, then we're going to land on Wednesday. If not, then I'll push it to Thursday."

"I'm really optimistic looking at the weather briefs, that things are going to play out really well for Kennedy," he added.

The shuttle must land by Friday, when its hydrogen batteries will run out.

STS-122 is the 121st shuttle mission and 24th mission to visit the space station. The next mission, STS-123, is slated to launch in March.

The mission STS-123 on space shuttle Endeavour will deliver the first pressurized section, Japanese Experiment Logistics Module (ELM-PS), of the future Kibo (Hope) Japanese module.

The Japanese Experiment Logistics Module, Pressurized Section it will contain critical avionics and serve as a storage area for experiment materials. At 14.4 feet in diameter and 12.8 feet in length, it is the smaller of two pressurized Japanese modules.

The mission STS-123 astronauts will be at Kennedy February 23-25 for the terminal countdown demonstration test, which is a full launch dress rehearsal to prepare for a targeted March 11 liftoff.

Endeavour's crew includes Commander Dominic Gorie, Pilot Gregory Johnson and Mission Specialists Rick Linnehan, Robert Behnken, Mike Foreman and the Japan Aerospace Exploration Agency's, Takao Doi.

Endeavour is launching with the expectation of staying in space for 16 days, and there are always extra days set aside in case weather or a technical problem delays landing.