Weather has delayed the launch of two Radiation Belt Storm Probes on an Atlas rocket, which was scheduled for today. This is the second time the launch has been delayed.

Launch crews are concerned about lightning and flight through cumulus clouds due to storm conditions south and east of Cape Canaveral. With Tropical Storm Isaac coming in, another launch attempt is not expected before August 30.

Weather has also forced the postponement of a Terrier-Improved Malemute sounding-rocket launch, carrying four student experiments, from NASA’s Wallops Flight Facility in Virginia. Again, this was the second time the launch was delayed. The first launch attempt, on Thursday, was delayed due to unauthorized boats in the launch area.

Weather delays are common, even in aviation, but current launch systems are much more susceptible to weather than modern aircraft are. The result is poor dispatch reliability. That’s not a major problem for the current launches – neither the Radiation Belt Storm Probes nor the student experiments are time-critical – but it can play havoc on missions that have limited launch windows, such as planetary missions.

Dispatch reliability will also be important for operational military missions, such as DARPA’s Space Enabled Effects for Military Engagements, and for future commercial missions. This may be an important operational advantage for ALASA, StratoLaunch, Launcher One, GO Launcher, and other airborne launch systems which have carrier aircraft that can fly around weather systems.