JOHNSON SPACE CENTER – The space shuttle is the world’s most complex machine. At $1.7 billion dollars apiece, it’s the most expensive, too.

So it is a little surprising to learn it carries AA batteries.

You’ll remember tests proved a suitcase size piece of foam smashed a hole in Columbia’s wing leading edge, which resulted in the orbiter’s fiery crash in 2003.

That led to the installation of sensors inside the wing. NASA installed 132 of them. Devices so sensitive, they can measure tiny taps or heavy hits during ascent or on orbit.

“I like to have it from my perspective because when we’re looking for potential ascent damage I want to personally look at all the data that’s out there,” said NASA Orbiter Project Office manager Steve Poulos.

For the first time though, something happened. The sensors are not working on Atlantis, which is scheduled to launch January 10.

NASA says they don’t matter. It can still launch Atlantis without them.

Think of it like a broken circuit.

All the sensors in the wings’ leading edge work fine. The problem is the device that transmits the data to the flight deck doesn’t work.

The reason?

Dead AA batteries.

A software malfunction drained them.

NASA says it can still use Atlantis’ robotic arm to scan the wings for damage.

Pictures of the vehicle beamed down from the space station help as well.

“Sometimes people will go off and do amazing things when you keep managers out of their way,” Poulos said smiling. “This is a classic example of engineers going out and coming up with a great solution to a difficult problem.”

Engineers in Houston bypassed the dead double AAs. They now think an antenna on board the Columbus laboratory can retrieve the data from the sensors, confirming whether anything strikes the shuttle when Atlantis finally gets off the ground.

So, why not just replace the batteries? They cannot be accessed on the launch pad.

Engineers can only get to them if NASA trucks the shuttle back to the assembly building.

A decision the space agency will likely make within days.