Editorial | The ESPA Saga Continues

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U.S. Air Force plans to begin regularly flying secondary payloads on Evolved Expendable Launch Vehicle (EELV) missions starting in 2014 would be worth getting excited about if not viewed through the jaded lens of experience.

The Air Force has pledged for years to make more frequent use of the EELV Secondary Payload Adapter (ESPA), a ring-shape device able to accommodate multiple small payloads on missions that do not require the full lift capability of the Atlas 5 or Delta 4 rocket. The ESPA ring debuted in 2007, and the following year then-Air Force Secretary Michael Wynne called on the service to begin making regular flights by 2012.

Since then, however, only one ESPA ring has flown, and that was on a NASA mission. The main reason appears to be reluctance among those responsible for the primary payload to take on hitchhikers that might add complexity to their mission.

That’s understandable given that program managers are judged on how their missions perform, but it’s not conducive to making flight opportunities available for small satellites and experiments. With NASA’s space shuttle retired and the venerable Space Test Program, which for decades has found rides to orbit for experimental Pentagon payloads, marked for termination, such opportunities could become all but nonexistent in the years ahead.

There are encouraging signs. ESPA manufacturer Moog CSA Engineering is reporting increased interest in the hardware, and the Air Force Research Laboratory has a program under way to develop a maneuverable variant.

The Air Force’s stated intent to fly ESPA rings once per year starting in 2014 is also encouraging. But small-satellite advocates and researchers who have been tracking the ESPA program since development began know better than to start popping champagne corks, especially in a funding environment where even the most modest, common-sense initiatives struggle for traction.