HOUSTON ?NASA?s shuttle Endeavour is headed for the launch pad as the space agency gearsup for its second construction flight of the year to the International SpaceStation (ISS).
Endeavour willcrawl out to Launch Pad 39A late Tuesday at 10:00 p.m. EDT (0200 July 11 GMT) afterpoor weather delayedan earlier rollout at NASA?s Kennedy Space Center in Cape Canaveral, Florida.
?We didn?tmake this morning?s 4:00 a.m. cutoff, but we are all set to go tonight,? said deputy shuttle program manager KimDoering, adding that the threat of lightning was to blame for the delay.
When theshuttle blasts off with fresh cargo and new ISS components on Aug. 7, its crewwill continue space station assembly. The orbiter will also carry BarbaraMorgan, NASA?s first educator astronaut, into space.
SinceEndeavour last flew in 2002, NASA technicians have replaced 2,500 of its heat-resistanttiles, installed thicker windows and added extra protection to the orbiter?sthermal blankets?among other upgrades?following the inadvertent loosening ofone during the STS-117 crew?s recent mission aboard Atlantis.
?We?re really excited to have Endeavourfly again,? Doering said in a Tuesday briefing.
The STS-118shuttle mission is slated to last 11 days, but could be extended three extradays pending on the success of a new system to transfer power from the ISS tothe orbiter.
Commandedby veteran spaceflyer Scott Kelly, the Endeavour?s crew includes seven astronauts,though Morgan is completing a unique 22-year journey that began as ChristaMcAuliffe?s backup for NASA?s former Teacher in Space Program.
?I?mexcited about experiencing the whole spaceflight, seeing Earth from space forthe very first time and experiencing weightlessness,? Morgan said in a NASAinterview.
Morgan willfunction as a fully trained mission specialist but will also interact withstudents and answer their questions while orbiting 220 miles (354 km) above theEarth.
In additionto Morgan and Kelly, the STS-118 crew includes shuttle pilot Charles Hobaugh,mission specialists Rick Mastracchio, Tracy Caldwell, Alvin Drew and DaveWilliams, who represents the Canadian Space Agency.
Matt Abbott,NASA?s lead STS-118 shuttle flight director, said the crew?s objectives will benumerous during their mission.
?There?s alittle bit of assembly, there?s some resupply, there?s some repairs and thereare some high-visibility education and public affairs events,? Abbott said.?It?s a little bit of everything.?
Theastronauts will attach the S5 starboard truss, a piece essential to connectinga future solar array to the ISS, as well a spare parts platform. They?ll alsoreplace a faultycontrol moment gyroscope (CMG) that helps NASA control the station?sposition in orbit.
Doeringnoted the crew could squeeze in extra work in preparation for the next shuttlemission, pending on whether or not a new power-sharing system called the station-shuttlepower transfer system (SSPTS) works. Added during Endeavour?slengthy overhaul, the system will allow a shuttle crew to squeeze in extraflight time by borrowing some of the station?s solar power and conservingEndeavour?s fuel cells.
NASAofficials explained that busy astronaut schedules should be expected over thenext three years to complete ISS construction work prior to the three-shuttle fleet?sretirement in September 2010.
?We?re readyto fly 118, and a lot of people have said ?boy, that?s quick,?? Doering said. ?Theteam has demonstrated that they can turn these vehicles around quickly. This isabout the pace we?ll be on?we?ll be flying roughly every other month.?
- NASA?s STS-118: Teaching the Future Through ISS Assembly
- SPACE.com Video Interplayer: Space Station Power Up with NASA's STS-117
- Complete Shuttle Mission Coverage