The CloudSat and CALIPSO launch has been delayed for at least 24 hours.
"The scrub is due to a suspect nitrogen temperature sensor on the rocket's second stage that may require replacement" - Bruce Buckingham, NASA spokesman.
The launch is now scheduled for 10:02 GMT on Friday.
The Launch of NASA's CloudSat and CALIPSO has been rescheduled for 10:02 GMT (6:02 a.m. EDT) on Thursday, April 27. Today's launch was delayed due to bad weather.
NASA's CloudSat and CALIPSO launch was scrubbed Tuesday shortly before 10:00 GMT (6 a.m. EDT) due to higher than allowable upper level wind conditions.
The next launch attempt is tentatively set for Wednesday, April 26, at 10:02 GMT (6:02 a.m. EDT), pending availability of all required Western Test Range assets. Weather is a concern for Wednesday's launch attempt. The forecast calls for a 40 percent probability of acceptable weather conditions. The primary concerns are for thick clouds, higher than allowable winds, rain showers and isolated thunderstorms.
NASA has postponing the launch of the CALIPSO and Cloudsat missions until Tuesday, April 25, 10:02 GMT (3:02 a.m ET), The weather forecast for Tuesday is predicted to have a 90 percent chance of acceptable conditions.
A NASA spokesman has confirmed that today's launch postponement was caused by problems with a refuelling aircraft for a downrange support launch tracking plane.