Heralded by its trademark twin sonic booms, space shuttle Endeavour returned to NASA’s Kennedy Space Center in Florida at 8:39 p.m. EDT, concluding the STS-123 mission with a smooth touchdown on Runway 15.

The landing came on the second, and final, opportunity of the day for the STS-123 crew. Cloud cover prevented a return on the day’s first landing chance - pushing the return home into the cover of night. It is the 16th night landing at the Kennedy Space Center.

Backup landing sites in California and New Mexico were not asked to be ready for a potential landing today.

Endeavour is being checked over by the landing convoy, a team of about 25 vehicles or units and 150 people who prepare the orbiter for towing and help the astronaut crew exit the winged spacecraft. The flight crew, commanded by astronaut Dominic Gorie, will leave Endeavour’s crew module shortly for brief medical exams.

The STS-123 crew began its mission March 11 and arrived at the International Space Station March 12. The astronauts delivered the Japanese Logistics Module - Pressurized Section (JLP), the first pressurized component of the Japan Aerospace Exploration Agency’s Kibo laboratory to the station. The crew of Endeavour also delivered the final element of the station’s Mobile Servicing System, the Canadian-built Dextre, also known as the Special Purpose Dextrous Manipulator.

Mission Specialists Richard Linnehan, Robert Behnken and Mike Foreman and Expedition 16 Flight Engineer Garrett Reisman conducted five spacewalks. Three of them included tasks devoted to the assembly of Dextre and the installation of related equipment. Dextre works with the orbital outpost’s robotic arm and resembles a human upper torso stick figure.

Other spacewalk activities included work to unberth the JLP, installation of spare parts and tools, installation of a materials experiment, replacement of a circuit-breaker box and demonstration of a repair procedure for tiles of the shuttle’s heat shield.

The spacewalkers also stowed the Orbiter Boom Sensor System, the extension of the shuttle’s robotic arm, onto the station’s main truss during the fifth spacewalk. The Japanese pressurized module to be launched on STS-124 is too large to accommodate the boom sensor in space shuttle Discovery’s payload bay.

Astronaut Garrett Reisman officially joined the Expedition 16 crew, trading places with European Space Agency astronaut Léopold Eyharts, who returned to Earth aboard Endeavour after almost 50 days in space.

STS-123 is the 122nd shuttle mission and the 25th station assembly mission. The next mission, STS-124, is slated to launch in May.

The crew of space shuttle Endeavour spent Tuesday getting ready for its journey home and the end of the STS-123 mission. Early in their day, the crew members performed a test of the thrusters that will be used to position the orbiter for re-entry and the control surfaces for its flight through the atmosphere.

The STS-123 astronauts also set up the recumbent seat for Mission Specialist Léopold Eyharts, who joined the crew of Endeavour on the International Space Station. The recumbent seat is a special seat designed to reduce the stress of gravity on those who have spent long periods of time in the weightless environment of space.

STS-123 arrived at the station March 12, delivering the Japanese Logistics Module - Pressurized Section, the first pressurized component of the Japan Aerospace Exploration Agency’s Kibo laboratory, to the station. The crew of Endeavour also delivered the final element of the station’s Mobile Servicing System, the Canadian-built Dextre, also known as the Special Purpose Dextrous Manipulator.

In addition the STS-123 astronauts delivered Expedition 16 Flight Engineer Garrett Reisman, who replaced Eyharts, a European Space Agency astronaut, on the station.

Endeavour is scheduled to land at Kennedy Space Center, Fla., at 7:05 p.m. EDT Wednesday.

If needed, a second landing opportunity is also available about 90 minutes later. NASA doesn’t plan to activate backup landing facilities in California or New Mexico on Wednesday.

The space shuttle Endeavour crew is expected to complete its 16-day flight to the International Space Station with a landing at NASA’s Kennedy Space Center on Wednesday, March 26.

The hatches between the two spacecraft closed at 5:49 p.m. EDT. However, plans to undock Endeavour from the International Space Station, originally set for 7:56 p.m., has been delayed because of a problem latching one of the ISS’s solar arrays.

Once the procedure takes place, it will end Endeavour’s 12-day stay at the orbital outpost.

The STS-123 mission began March 11 and delivered the first segment of the Japan Aerospace Exploration Agency’s Kibo laboratory and the Canadian Space Agency’s two-armed robotic system, known as Dextre. The flight also brought a new crew member to the station and will return an astronaut who has spent nearly seven weeks aboard the complex.

NASA managers will evaluate weather conditions at Kennedy before permitting Endeavour to return to Earth. Wednesday landing opportunities at Kennedy are at 7:05 p.m. EDT and 8:39 p.m. The shuttle’s backup sites for landing, Edwards Air Force Base, Calif., and White Sands Space Harbor, N.M., will not be activated Wednesday.

The crews of space shuttle Endeavour and the International Space Station have completed their last full day together.

Much of the astronauts’ morning was off?duty time. Afterward, the crews wrapped up transfers of equipment and supplies between Endeavour and the station, and they checked out the tools needed for undocking and subsequent activities.

The STS-123 and Expedition 16 crews also held a joint crew news conference, answering questions from members of the media on Earth.

Endeavour will undock from the station at 7:56 p.m. EDT Monday and begin its journey back to Kennedy Space Center, Fla.

Capping a series of five spacewalks, astronauts Robert L. Behnken and Mike Foreman completed the final spacewalk of the STS-123 mission at 9:36 p.m. CDT on Saturday. Their 6-hour, 2-minute excursion was highlighted by the positioning of robotic boom to its temporary home on the space station, as well as installation of the Materials International Space Station Experiment-6 (MISSE-6) and inspection of the station?s right Solar Alpha Rotary Joint (SARJ).

This was the 109th dedicated to the assembly of the space station. Because the two made quick work of the major tasks, they also were able to remove trunnion covers on the Japanese Logistics Pressurized Module.

Behnken and Foreman, on the third spacewalk for each, first stored the Orbiter Boom Sensor System — or OBSS — on the station?’s truss. Normally, the OBSS is returned on the space shuttle but this time it is being left on the station because there is not enough room in the cargo bay of space shuttle Discovery to house the next Japanese component to the station ? the massive Kibo science laboratory. Discovery will bring the OBSS back to Earth at the end of the STS-124 mission.

After the OBSS was stored, the two spacewalkers split up for other tasks. Behnken installed the MISSE-6 on the outside of the Columbus laboratory while Foreman inspected the SARJ.

The 10-foot-wide, 2,500-pound joint, which rotates the station?s starboard solar arrays to track the sun, began showing increased vibrations and power usage last fall. Previous inspections have found metal shavings under the rotary joint?s insulation covers, and Foreman again looked at an area previously photographed to better characterize an apparent pockmark.

This time around Behnken had no trouble with MISSE-6 thanks to a few troubleshooting methods developed by engineers on the ground. He and Mission Specialist Rick Linnehan had attempted to install the MISSE-6 experiment during the mission?s third spacewalk, but were unable to engage latching pins used to hold the experiment packages onto the hull of Columbus.

Astronauts Bob Behnken and Mike Foreman completed the fourth spacewalk of Endeavour’s STS-123 mission on Friday. The duration of the spacewalk was 6 hours 24 minutes, and it was the 108th spacewalk in support of the construction of the International Space Station.

Behnken and Foreman replaced an electrical circuit box called a Remote Power Controller Module (RPCM) on the station’s truss. One of the goals of the task was to restore redundant power to control moment gyroscope (CMG) 2, but the astronauts were unable to remove one of the connectors from the Z1 truss. CMG-2 will continue to operate on its primary RPCM until that connector is removed.

The major focus of Friday’s spacewalk was a demonstration of the Tile Repair Ablator Dispenser — a caulk-gun-like device — and the application of a substance called Shuttle Tile Ablator-54 (STA-54) into intentionally damaged heat shield tiles. The astronauts applied the STA-54 into various molds, including a few that were created to resemble damage seen on previous shuttle missions and damaged tiles from prior flights. The test samples will be returned to Earth to undergo extensive testing on how STA-54 performs in both a microgravity and vacuum environment.

Behnken and Foreman also removed a cover from Dextre, the station’s new robotic attachment, and some of the launch locks that were still attached to the Harmony module. Those locks were removed in preparation for the arrival of the pressurized Japanese Kibo laboratory aboard Discovery in May.

Mission managers on the ground are continuing to assess what is believed to be a software error involving the shoulder roll joint of Dextre. The shoulder joint had been working properly yesterday, but commands detected errors as the teams worked through power-up procedures. Both of Dextre’s arms are currently stowed in their proper position.

Mission Specialists Robert L. Behnken and Mike Foreman completed the fourth STS-123 spacewalk at 12:28 a.m. EDT, spending six hours and 24 minutes on the excursion.

As the docked International Space Station and space shuttle Endeavour orbited high above the Earth, the two shuttle crew members replaced a failed Remote Power Control Module – essentially a circuit breaker – on the station’s truss. However, there were difficulties removing a power connecter from the Z1 truss.

With Mission Specialist Rick Linnehan coordinating their activities from inside the orbiting complex, the spacewalkers also tested a repair method for damaged heat resistant tiles on the space shuttle. This technique used a caulk-gun-like tool named the Tile Repair Ablator Dispenser to dispense a material called Shuttle Tile Ablator-54 into purposely damaged heat shield tiles. The sample tiles will be returned to Earth to undergo extensive testing on the ground.

Endeavour’s crew will perform a final inspection of the orbiter’s heat shield tiles Friday using the Orbiter Boom Sensor System (OBSS).

Behnken and Foreman will begin the mission’s fifth and final spacewalk Saturday at 5:23 p.m. Among other tasks, they will stow the OBSS on the station’s main truss to be retrieved by the crew of Discovery on STS-124, the next space shuttle mission.

In a day highlighted by robotics activity, the Canadian-built Dextre was attached to a power and data grapple fixture located on the U.S. laboratory Destiny. The new robotic system is the final element of the International Space Station’s Mobile Servicing System.

Mission Specialists Rick Linnehan and Mike Foreman finished assembling Dextre Sunday during the second spacewalk of STS-123.

Canadarm2, the International Space Station’s robot arm, grabbed the pallet that secured Dextre during its journey to the orbital outpost and returned the pallet to space shuttle Endeavour’s payload bay for the trip back to Earth.

The station and shuttle crews also prepared hardware to be used in a shuttle tile repair test on the next spacewalk, and they got some much needed off duty time.

Foreman and Mission Specialist Robert Behnken are slated to begin the mission’s fourth spacewalk at 6:28 p.m. Thursday. The two will perform tasks that include the shuttle tile repair test and change out of a circuit breaker on the station.

Now almost halfway through their 16-day mission, and with two spacewalks under their belts, space shuttle Endeavour’s crew members will focus on getting the cargo they brought to the station up and running.

The crew members were awakened at 2:43 p.m. with ‘God of Wonders’ by Caedmon’s Call. The song was played for Endeavour’s commander, Dominic Gorie.

Just before the crew went to sleep Sunday morning, flight controllers on the ground began checking out systems on Dextre - the Canadian Space Agency’s Special Purpose Dexterous Manipulator. Those tests wrapped up at 6:18 a.m., and were all successful.

Mission Specialist Robert L. Behnken and station Flight Engineer Garrett Reisman will pick up where the ground teams left off. Behnken will go through a series of tests to make sure the brakes on the joints on the two 11-foot arms on the robot work. At 10:48 p.m., Behnken will stow Dextre in the configuration needed for the third spacewalk of the mission by him and Rick Linnehan Monday night, when the assembly of Dextre will be completed.

Behnken and Linnehan will be starting their campout in the Quest Airlock for that spacewalk at 3:43 a.m., but before they do that, they’ll join Mission Specialists Mike Foreman, Reisman and station Commander Peggy Whitson for a set of interviews with reporters on the ground. KMOX Radio in St. Louis, WEWS-TV in Cleveland and WBZ-TV in Boston will be talking with the astronauts at 9:18 p.m. All three stations are all in cities close to crew members’ hometowns: Behnken, Linnehan and Foreman are from Missouri, Massachusetts and Ohio, respectively.

Work inside the Japanese Experiment Logistics Module, Pressurized Section, continues to be ahead of schedule. Japanese Aerospace and Exploration Agency Astronaut Takao Doi will be doing get-ahead tasks today for the STS-124 mission, when space shuttle Discovery will bring up the second Japanese component, the large Kibo pressurized laboratory.

Dextre, the final element of the International Space Station’s Mobile Servicing System, was put together today during the second spacewalk of STS-123. Mission Specialists Richard Linnehan and Mike Foreman completed their 7-hour, 8-minute orbital stroll Sunday at 2:57 a.m. EDT.

The two spacewalkers assembled the stick-figure-shaped Dextre, also known as the Special Purpose Dextrous Manipulator (SPDM), a task that included attaching its two arms.

Designed for station maintenance and service, Dextre is capable of sensing forces and movement of objects it is manipulating. It can automatically compensate for those forces and movements to ensure an object is moved smoothly.

Throughout the day, the station and shuttle crew members continued outfitting the Japanese Logistics Module - Pressurized Section (JLP). The JLP is the first pressurized component of the Japan Aerospace Exploration Agency’s Kibo laboratory and the newest component of the station.