Thisstory was updated at 10:22 p.m. EDT.
HOUSTON -Astronauts aboard NASA?s shuttle Endeavour converted their spacecraft into a100-ton glider Tuesday as they head home from a packed construction flight tothe International Space Station (ISS).
Endeavourcommander Dominic Gorie and pilot Gregory H. Johnson fired thrusters andtested flight control systems that will allow their spacecraft to once more flythrough the Earth?s atmosphere for a planned Wednesday landing in Florida.
?In myview, it?s been an extraordinary way in every way that I can think of,? saidLeRoy Cain, chair of Endeavour?s STS-123 mission management team, on Monday.?It?s just been a textbook mission up and down the line.?
Endeavourand its crew departedthe space station late Monday after 12 days of joint orbital construction -the longest period yet for a visiting crew. They performed a record fivespacewalks while at the station to install an attic-like storage module forJapan?s massive Kibo laboratory and construct a Canadian-builtmaintenance robot affectionately dubbed ?Mr. Dextre.?
?We?ve donejust awesome,? Gorie said of his crew before leaving the station.
Theastronauts also left Endeavour?s heat shield inspection boom attached to theISS so the crew of NASA?s next shuttle to fly can haul the rest of Japan?s schoolbus-sized Kibo lab to the station. That module, set to launch May 25 aboardDiscovery, is so large the shuttle cannot carry its own inspection pole.
During abreak in their flight systems checks, Johnson and crewmates snacked on whatappeared to be jelly beans, which they playfully tossed around ? bag included -while floating in Endeavour?s flight deck.
?We appreciatethe entertainment, unfortunately we have to ask you to get back to work here alittle bit,? Mission Control radioed up to the crew. The rest of the checkoutswent well.
Returningto Earth
Gorie andJohnson also fired Endeavour?s thrusters today in an ultra-brief maneuver, justsix seconds at most, to gain an extra 4 feet per second (1.2 mps) invelocity. But the small boost gives their spacecraft two chances to landat NASA?s Kennedy Space Center in Cape Canaveral, Fla., on Wednesday.
The firstlanding opportunity arises before sunset at 7:05 p.m. EDT (2305 GMT), with asecond window opening at 8:39 p.m. EDT (0039 March 27 GMT). Early forecastsfrom NASA?s Spaceflight Meteorology Group here at the Johnson Space Centerpredict favorable conditions at landing time.
?We?ve hada really great time up here,? said astronaut Mike Foreman, a mission specialistwho performed three of the five spacewalks during Endeavour?s flight. ?Butyeah, I think a few of us are thinking about getting back to planet Earth.?
One suchspaceflyer is Frenchastronaut Leopold Eyharts, who arrived at the station during a Februaryshuttle mission to install and outfit the European Space Agency?s (ESA)Columbus laboratory. NASA astronaut Garrett Reisman, who launched withEndeavour?s crew, replaced Eyharts as a member of the station?s Expedition 16crew.
?Up to youGarrett, it?s your turn,? Eyharts said as he passed his flight engineer mantleto Reisman. ?C?est la vie.?
Astronautswill due to spend some time today setting up a special recumbent seat onEndeavour?s middeck that will allow Eyharts, who will have spent almost 50 daysin space by landing, to weather the return to Earth?s gravity in a reclinedposition.
?I?mpreparing for that,? Eyharts said. ?I?m trying to do exercises regularly, butI?m quite confident because just a couple of months is not so much.?
Mission Controlwoke Endeavour?s crew this morning with the Italian song ?Con Te Partiro? byAndrea Bocelli in an orbital tribute to Eyharts? homecoming.
"I'dlike to see everybody back on Earth," Eyharts told flight controllers."Thanks a lot for the music and see you very soon."
Stationtraffic heats up
Eyhartssaid he was more worried about his former station crewmates - Expedition 16commander Peggy Whitson and flight engineer Yuri Malenchenko - who are on asix-month mission and have a busy few weeks ahead of them with Reisman.
The ESA?sfirst unmannedcargo ship Jules Verne is due to make the first of two test approaches atthe station on Saturday before docking in earnest on April 3. A relief crew foralso due to launch on April 8 aboard a Russian rocket, kicking off a busyhandover that will end with the April 19 landing of Whitson, Malenchenko and aSouth Korean astronaut to arrive with their replacements.
NASA,meanwhile, is also forging ahead with plans for Discovery?s STS-124 mission todeliver the main section of Japan?s Kibo lab to the ISS. The shuttle?s externalfuel tank is due to arrive at the Kennedy Space Center as early as today,mission managers have said.
Cain saidthe U.S. agency is also looking at ways to streamline streamlining the manufacturingand testing of new, modified shuttle fuel tanks to avoid delays that may impactflights later this year, such as the planned Aug. 28 launch of Atlantis tooverhaul the Hubble Space Telescope.
?We?ll takethe time we need to work through the problem and it?s not going to be an impactfrom a station assembly standpoint,? Cain said.
Thisstory was written at NASA?s Johnson Space Center in Houston and updated in CapeCanaveral, Fla. SPACE.com staff writer Clara Moskowitz contributed to thisreport from New York City.
NASA isbroadcasting Endeavour's STS-123 mission live on NASA TV. Click here for SPACE.com'sshuttle mission coverage and NASA TV feed.
