United Launch Alliance Atlas 5 lift off scrubbed by on board C-band beacon problem. Photo Credit: NASA TV
NASA's Radiation Belt Storm Probe twin spacecraft mission lift off was scrubbed early Friday due to indications of a C-band tracking beacon problem aboard the United Launch Alliance Atlas 5 booster late in the countdown.
Launching of the $686 million mission from Space Launch Complex-41 at Cape Canaveral Air Force Station, Fla., was provisionally re-scheduled for Saturday at 4:07 a.m., EDT, pending further evaluation of the issue.
The weather outlook included a 60 percent chance of favorable conditions.
Efforts to lift off Friday at 4:07 a.m., EDT were pushed to 4:25 a.m., then scrubbed as the 20 minute launch period neared expiration.
"The C band tracking beacon on the launch vehicle was drifting from the [U. S. Air Force Eastern Test Range] system that picks [the signal] up," said Tim Dunn, the NASA launch director for the mission. "This is a mandatory safety item so that we can track the vehicle in flight. We had a frequency drift that was occurring. With the limited launch window, we did not have enough time to evaluate the cause."
Air Force and NASA tracking of the spacecraft is restricted to several sources, reflections from ground based radar, telemetry from spacecraft instrumentation, optical tracking with cameras and the C-band beacon. The source of the difficulties could rest with equipment on the spacecraft or the Air Force range assets, Dunn said.
The mission could face further delays if the beacon on the launch vehicle has to be replaced.
Findings from the $686 million two-year RBSP mission are expected to improve the forecasting of space weather events that can affect communications and GPS satellite operations; alter radiation levels encountered by airline crews and passengers on polar routes as well as astronauts aboard the International Space Station; and disrupt terrestrial power grids.
The mission includes two identical 1,400 pound spacecraft developed by the Applied Physics Laboratory to study high energy fluctuations within the Earth's Van Allen radiation belts. The radiation-hardened probes are designed to orbit the equator between 300 and 19,000 miles, moving in and out of the two belts to characterize the intensity and dimensions of high energy fluctuations.