Super-low-mass spaceborne SAR array concepts

For Earth remote sensing applications, a synthetic aperture radar (SAR) typically employs an antenna with a fairly long along-track aperture in order to achieve the desired performance. At orbital velocities, the antenna along-track dimension is driven by a careful trade off between resolution, swath width, and available data rate and is independent of wavelength. 10 to 20 m long antennas have been flown or proposed in previous spaceborne SAR designs. To maintain an acceptable electrical flatness across this long aperture, very massive antenna support structures, weighing several hundred kilograms or more, have been used to date. These massive antenna systems generally require a launch vehicle with large stowage volume and heavy-payload-lift capability. To achieve good launch volume efficiency and to reduce payload weight, three super-low-mass array concepts are proposed and described. With these new concepts, the mass of the future Earth remote sensing SAR antennas is expected to be less than 100 kg.