NASA will refill space shuttle Endeavour's external fuel tank tomorrow morning to test whether the leak that twice scrubbed the orbiter's launch earlier this month has been properly repaired.

The refueling is scheduled to commence at 7:00 A.M. (Eastern Daylight Time), and Florida Today reports that the tank will reach 98 percent capacity, the level at which leaks arose during launch preparations, between 9:00 and 9:15 A.M.

NASA passed on launch opportunities June 13 and June 17 after hydrogen leaks were discovered at the launch pad. The culprit was the Ground Umbilical Carrier Plate, which is where the external fuel tank connects to a venting system that allows excess hydrogen to be carried away from the orbiter.

After failing to get the shuttle Endeavour off the launch pad this week, NASA had better luck with its mission to map the moon.

An Atlas V rocket lifted off from Florida's Cape Canaveral Air Force Station carrying the Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS). The spacecraft are expected to reach lunar orbit Tuesday morning, and NASA has been tweeting about mission as it unfolds.

Within hours of blastoff, NASA established communication with the LRO to power up the systems needed to control the spacecraft, which will circle the moon at an orbit of 31 miles (50 kilometers) for at least one year to study the lunar surface and scope out potential landing sites for a possible manned moon mission in 2020.

Another hydrogen leak will keep the space shuttle Endeavour's crew on the ground for another month while NASA investigates the problem. The space agency scrubbed today's scheduled launch early this morning when a gaseous hydrogen leak was detected at the same location where a similar leak halted the shuttle's original June 13 launch.

"We're going to step back and figure out what the problem is and go fix it," Deputy Space Shuttle Program Manager LeRoy Cain said in a statement. Even if all goes well, NASA expects the shuttle to launch no earlier than July 11.

NASA engineers found the leak at the Ground Umbilical Carrier Plate (GUCP), which is the vent to the launch pad and the flare stack (or elevated chimney) where the vented hydrogen is burned off. (For pictures of what the GUCP looks like, visit GalaxyWire.net.) The venting system (pdf), located outside the shuttle's external fuel tank, is designed to carry excess hydrogen safely away from the launch pad as the Endeavor blasts off. During launch, the external fuel tank supplies the shuttle's main engines with liquid oxygen and hydrogen propellants.

As NASA engineers ponder how the shuttle Endeavor's gaseous hydrogen venting system started leaking and delayed the spacecraft's launch, the agency said it will try to put the shuttle in orbit on Wednesday at 5:40 a.m. ET. The shuttle's problems likewise push the launch of the moon-probing Lunar Reconnaissance Orbiter (LRO) and Lunar Crater Observation and Sensing Satellite (LCROSS) back at least one day, to Thursday, June 18.

NASA believes a seal on the external fuel tank that was misaligned when it was coupled to one of the shuttle's engines caused the leak, NASA Shuttle Test Director Stephen Payne, said today during a press conference. "Our teams have been working very hard over the last couple of days to get this piece of equipment fixed," he said, adding, however, that the space agency was unsure of what's causing the misalignment.

Residents of southern California were treated to a pair of sonic booms as the U.S. space shuttle Endeavour passed overhead yesterday en route to its safe landing at Edwards Air Force Base.

Bad weather had forced the crew to divert its destination from Kennedy Space Center in Florida to Edwards. The Associated Press reports it will cost about $1.8 million to bring the shuttle back to Florida on of the back of a modified jumbo jet.  

"The sonic boom sounded like a nearby explosion, very low and deep. It reminded me of a thunderclap, but shorter and with a softer timbre," screenwriter John Aboud of South Pasadena told ScientificAmerican.com in an e-mail.
 

After five days of ill-fated attempts, International Space Station (ISS) astronauts today ran two successful tests of equipment on board designed to turn urine, sweat and moisture from the air into drinking water, NASA.gov reports. NASA now must decide whether the contraption, deemed essential for hydration of future astronauts traveling farther out into space, should return with the space shuttle Edeavour on Sunday or remain on the ISS for further testing,  according to the Associated Press.

After some tinkering (including installation of new support brackets to secure the system's centrifuge) by station commander Mike Fincke and shuttle mission specialist Don Pettit, the Urine Processor Assembly (part of the station's new Water Recovery System), successfully finished a full five-hour run, Space.com reported today. The astronauts successfully operated the system again three hours later after it cooled down. The $154 million water recycling system is part of a $250 million regenerative life support system designed to sustain larger space station crews with fewer supply drop-offs from visiting spacecraft, Space.com reports; the first six-person crew (currently there are only three astronauts on board at a time when there isn't a visiting spacecraft) is due to arrive at the orbiting lab next May.

Bye-bye, grease gun.

An astronaut cleaning a solar rotary joint on the International Space Station lost her 30-pound tool bag yesterday, sending two grease guns, a scraper, a garbage bag and wipes into the cosmos, NASA reports.

"Oh, great," said astronaut Heidemarie Stefanyshyn-Piper as the bag drifted away. "You see it?"

The slip-up occurred about midway into the nearly seven -hour spacewalk. Piper was about to lubricate the rotary joint, which is clogged with metal shavings, when the gun squirted grease into her tool bag. As she was cleaning out the bag, it drifted away. She and astronaut Steve Bowen shared a second set of tools for the rest of the spacewalk.

When the space shuttle Endeavour launches next Friday, its payload will include more than just servicing equipment for the International Space Station (ISS). The shuttle is also slated to carry a copy of the Universal Declaration of Human Rights, an international analogue of the U.S. Bill of Rights, for permanent placement on board the ISS as the document nears its 60th birthday.

The Universal Declaration, adopted by the U.N. General Assembly on December 10, 1948, forms the basis of international human rights law, proclaiming in its first article that "All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood." In a European Space Agency (ESA) statement, French astronaut Léopold Eyharts said that "in recognition of the fact that human beings are at times downtrodden, the Declaration can symbolically find its place 'above' all the peoples of the world."