U.S. Air Force Radar Problem Delays NROL-67 and SpaceX CRS-3 Launches

©U.S. Army

File photo of MOTR radar at White Sands.

A problem with the U.S. Air Force AN/MPS-39 Multiple Object Tracking Radar (MOTR) at the Eastern Range, reportedly a fire, has delayed the launch of the National Reconnaissance Office's NROL-67 launch and now unofficially SpaceX's launch of the CRS-3 resupply mission to the International Space Station.

Yesterday, United Launch Alliance tweeted that "Prior to the 1st #NROL67 launch attempt Mar 25, an issue developed with a @45thSpaceWing mandatory range asset needed to support the launch."

Through sources at the NASASpaceflight forum that asset was identified as the Air Force MOTR 19.39 radar, though the Air Force has yet to publicly comment or confirm that this is the asset with the problem.


MOTR radar just south of the Kennedy Space Center Visitor Complex. Credit: Google Maps.

According to U.S. Army which uses the MOTR at White Sands are the "are phased array radars, each capable of simultaneously tracking up to 40 objects within a scan volume of 60 degrees by 60 degrees. Each MOTR phased array antenna is mounted on an azimuth over elevation pedestal so that full hemispheric coverage is possible. The precision of the radar is 0.2 mils (approximately .02 milliradians) in angles and 1.5 yards in range. The peak power of the radar is one-megawatt, but a mix of six different waveforms provides for a total average transmitted power of 5000 watts, the highest of any of the WSMR radars. The MOTR is capable of tracking a six-inch sphere to range in excess of 120 km."

The MOTR radar was developed in the 80's and put in service in the 90's. There are only a handful in operation globally today.

It is not known at this time how long a delay will be before the radar is fixed. This could also push back the Cape's launch schedule beyond the NROL-67 and SpaceX CRS-3 launches. This depends on the seriousness of the presumed fire and available spare parts or manufacturing of new parts.

A plan to upgrade the Eastern Range has been in the works for several years. The Launch and Test Range System (LTRS) Integrated Support Contract (LISC), a 10-year contract that consolidates three contracts currently supporting the Air Force's launch ranges at Cape Canaveral Air Force Station, Florida and Vandenberg Air Force Base, California was delayed until no earlier than the second quarter of this year.

Images credit: Courtesy Col. Rob Uemura, U.S. Air Force, presentation at the 15th FAA Commercial Space Transportation Conference (2012).

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