Staring at the Sun, You’ve Gotta Wear (Sun)shades Space weather from our Sun affects everything from auroras to how we protect our power grid, satellites, and astronauts. However, the origins of space weather, including solar flares, coronal mass ejections and the solar wind, remain a mystery despite decades of study. To study the solar atmosphere, or corona, just above the visible surface, scientists need a meterswide sunshade to block out the massive amounts of light continually pouring from the surface itself, said Goddard heliophysicist Doug Rabin. Scientists also need an instrument that can sense extreme ultraviolet features that could be just a few miles wide, at the distance of the Sun — an angular resolution that no current Sun-observing satellites can match. “In order to meet those needs, we are trying to make a distributed telescope,” Rabin said. “The lens and the detector are on different spacecraft. Currently, 15 meters is about the maximum focal length of a single spacecraft with a rigid extensible boom. We’re looking at enabling focal lengths of 50 meters, one kilometer, or more.”
In its current iteration, his observatory concept features a lens, centered in a meters-wide sunshade, flying in precision formation with a detector 100 meters away. The two spacecraft could not drift out of alignment by more than a millimeter in the 100-meter focal length, or 10 to 20 microns — a fraction of the width of a human hair — side-to-side. During the COVID-19 shutdown, Rabin worked remotely with Anne-Marie Novo-Gradac (lead), Philip Calhoun, Adrian Daw, Irving Linares, and Guan Yang on the problems of how to precisely measure the two spacecrafts’ alignment (CuttingEdge Summer 2020, P. 2), as well as developing the sunshade mechanics. Team member Anne-Marie Novo-Gradac conceived a novel sunshade concept that plays off tissuepaper fans often used as party decorations. The team’s version substitutes a plastic material for paper and uses thin spring steel as structural ribs. The ribs and the plastic webbing between them begin their journey wrapped compactly around the lens tube itself. The team’s sunshade is smaller Continued on page 12
Anne-Marie Novo-Gradac tests the unfurling of a meter-wide proof of concept prototype sunshade in her back yard.
www.nasa.gov/gsfctechnology
Photo credit; Kevin J. Novo-Gradac
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cuttingedge • goddard’s emerging technologies
Volume 18 • Issue 2 • Winter 2021
