Early this morning the Atlas V carrying the twin Radiation Belt Storm Probe spacecraft started the countdown to launch early this morning. After experiencing a small problem with a fuel valve the countdown continued smoothly and entered the programmed hold at T-4.
It was during this hold that a problem was found with a critical range tracking beacon. Unfortunately this was unable to be resolved within the available time causing the launch to be scrubbed. There was no issue with the Atlas V, Centaur or the RBSP spacecraft.
The range tracking beacon is one of the few instruments that allow engineers to monitor the flight of the rocket on its way into orbit. This is a mandatory item on the checklist and failure means an automatic hold in the countdown process.
The launch has been rescheduled for 4:07am EDT (8:07 GMT) tomorrow 25th August, pending successful diagnosis and resolution of the range tracking beacon. The weather forecast indicates a 60% chance of good conditions at launch time.
The official scrub statement from ULA and some more launch pad photos follow:
The launch of an Atlas V carrying NASA’s twin Radiation Belt Storm Probes (RBSP) mission was scrubbed today due to an issue with the mandatory range tracking beacon.
The Atlas V vehicle and RBSP are safe and secure at this time. The launch is rescheduled for Saturday, Aug. 25 from Space Launch Complex-41 at Cape Canaveral Air Force Station, Fla. The launch time is 4:07 a.m. EDT. The forecast for Aug. 25 shows a 60 percent chance of favorable weather conditions for the launch tomorrow.