Compact and Light-Weight Solar Spaceflight Instrument Designs Utilizing Newly Developed Miniature Free-Standing Zone Plates: EUV Radiometer and Limb-Scanning Monochromator

Monday, 15 December 2014
John Francis Seely1, Donald R McMullin1, James Bremer1, Chieh Chang2, Anne Sakdinawat2, Andrew R Jones3 and Robert Vest4, (1)Space Systems Research Corporation, Alexandria, VA, United States, (2)Stanford University, Stanford, CA, United States, (3)Laboratory for Atmospheric and Space Physics, Boulder, CO, United States, (4)National Institute of Standards and Technology Gaithersburg, Gaithersburg, MD, United States
Two solar instrument designs are presented that utilize newly developed miniature free-standing zone plates having interconnected Au opaque bars and no support membrane resulting in excellent long-term stability in space. Both instruments are based on a zone plate having 4 mm outer diameter and 1 to 2 degree field of view. The zone plate collects EUV radiation and focuses a narrow bandpass through a pinhole aperture and onto a silicon photodiode detector.

As a miniature radiometer, EUV irradiance is accurately determined from the zone plate efficiency and the photodiode responsivity that are calibrated at the NIST SURF synchrotron facility. The EUV radiometer is pointed to the Sun and measures the absolute solar EUV irradiance in high time cadence suitable for solar physics and space weather applications.

As a limb-scanning instrument in low earth orbit, a miniature zone-plate monochromator measures the extinction of solar EUV radiation by scattering through the upper atmosphere which is a measure of the variability of the ionosphere.

Both instruments are compact and light-weight and are attractive for CubeSats and other missions where resources are extremely limited.