Astronauts back in Florida for Endeavour’s final mission on May 16

Monday will mark the second scheduled launch for Endeavour after the first attempt on April 29 was scrubbed four hours before take off because of a heater malfunction detected in the shuttle.

After the switch box was replaced and new electrical wiring connecting the switchbox to the heaters was installed, the space shuttle is now ready for liftoff.

"It's great to be back," said Kelly. "We really appreciate all the hard work by the team that's worked over the last couple of weeks to get shuttle Endeavour ready."

"We've kind of end-to-end checked and wrung out the whole system … and now have extremely high confidence that the problem is no longer in the ship or in any of the electronics.”-- Space Shuttle Launch Integration Manager Mike Moses

A damaged fuse box halted planned mission
NASA chose to halt Endeavour's planned mission on April 29 when a failed fuse box prevented heaters on a hydraulic system fuel line from turning on.

Trouble was detected in one of the auxiliary power units (APU) of the shuttle’s engine compartment during testing.

The forensic engineers are still uncertain what caused a short circuit inside the power box.

However, the technicians have replaced the box and a thermostat and also repaired and retested the electrical circuitry between the box and the fuel line heaters. NASA did not replace any of the heaters.

Space Shuttle Launch Integration Manager Mike Moses stated, "We've kind of end-to-end checked and wrung out the whole system … and now have extremely high confidence that the problem is no longer in the ship or in any of the electronics.”

He added, "We have nothing in front of us preventing us from launching on the 16th."

Agenda of the next to the last mission
If there are no technical hitches and good weather prevails, Endeavour’s crew of six astronauts plan to take off on the space shuttle’s final mission to the International Space Station (ISS) on May 16.

In its 25th flight over a 16-day mission, the shuttle is slated to deliver the Alpha Magnetic Spectrometer (AMS), a particle physics experiment device built to search the universe for dark matter and antimatter.

The other items include the final of four Express Logistics Carriers and some spare parts including two S-band communications antennas, a high-pressure gas tank, spare parts for Dextre and micrometeoroid debris shields to the to the ISS.

The STS-134 mission also includes four spacewalks, the final scheduled spacewalks by shuttle astronauts.

After Endeavour, Atlantis will blast off on the final space shuttle mission in June or July.