Weather conditions kept NASA's Radiation Belt Storm Probes or RBSP on Space Launch Complex 41 at Cape Canaveral Air Force Station.

Weather conditions associated with lightning, as well as cumulus and anvil clouds, kept NASA's Radiation Belt Storm Probes, or RBSP, on Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida. The twin probes are awaiting launch atop a United Launch Alliance Atlas V rocket.

RBSP will explore changes in Earth's space environment caused by the sun -- known as "space weather" -- that can disable satellites, create power-grid failures and disrupt GPS service. The mission also will provide data on the fundamental radiation and particle acceleration processes throughout the universe. The launch is rescheduled for 4:05 a.m. EDT on Aug. 30, pending approval from the range. For more information on RBSP, visit http://www.nasa.gov/rbsp. Photo credit: NASA/Gary Thompson