Bad weather has moved NASA to delay the launch of the Radiation Belt Storm Probes once again. The liftoff is now scheduled for Aug. 30 at 4:05 a.m.

A tracking beacon glitch stopped the countdown Friday morning, during a better weather window. As the storm approaches, NASA is not taking any chances.

“With the unfavorable weather forecast as a result of Tropical Storm Isaac approaching Florida, the leadership team for launching NASA’s Radiation Belt Storm Probes (RBSP) mission has decided to roll the Atlas V rocket off the launch pad and back to the Vertical Integration Facility at Cape Canaveral Air Force Station’s Space Launch Complex 41,” NASA said in a statement. “This will ensure the launch vehicle and twin RBSP spacecraft are secured and protected from inclement weather.”

NASA will try again on Thursday.