Cape Canaveral, Fla. ? NASA on Tuesday postponed the launch of space shuttle Discovery from May until at least July because of an all-too-familiar problem: a faulty fuel tank sensor.

A similar problem briefly delayed last summer’s launch of Discovery on the first shuttle flight since the Columbia disaster in 2003.

NASA said it needs the time to open the spacecraft’s hydrogen fuel tank and replace the sensor, which gave an electrical resistance reading that was slightly off.

The space agency also plans to replace the three other sensors in the tank, to be safe.

Despite the delay, Hale said he was still confident NASA would be able to launch three shuttles this year.