From the joint JPL-Pumpkin ISARA project that began in 2012, today the 3U ISARA spacecraft is on-orbit and undergoing initial trials. ISARA is equipped with a deployable 24-cell Pumpkin PMDSAS solar array that also has a Ka-band reflectarray antenna on its backside. The conductive pattern on the reflectarray side is analogous to a Fresnel lens for Ka-band wavelengths, implemented as discrete patches arranged in a particular pattern. Pumpkin worked with Dr. Richard Hodges and his group at JPL to develop a process whereby the JPL-designed reflectarray could be incorporated into Pumpkin's PMDSAS deployable solar panel technology and manufacturing, to yield flat and extremely stiff dual-purpose panels. Naturally, Pumpkin's space-grade hinges were used on these panels.
In the images above, you can see the backside of the deployed Pumpkin 3-panel solar array + reflectarray. The metallic-color pieces between the panels are the Pumpkin hinges that enable the reflectarray to wrap around the ISARA structure when stowed. Solar power (from the solar cells on the opposite sides of these panels, not visible in these images) is routed from the central panel into the 3U bus at the hinge interface located at the base of the center panel. The smaller 4x4 array of patches on the opposite side of these fisheye-view images captured on orbit is the feed antenna for the reflectarray.
Dr. Hodges reported on January 16 that the Pumpkin solar array is functioning properly. The Aerospace Corporation is currently doing checkout of the various spacecraft bus components (e.g., Star Tracker and ACS). We wish them luck with this ground-breaking effort!
On-orbit images courtesy of JPL / NASA. More information at https://www.jpl.nasa.gov/cubesat/missions/isara.php.