An emerging super-black nanotechnology that is to betested for the first timethis fall on the International Space Station will be applied to a complex, 3-D component critical for suppressing stray light in a new, smaller, less-expensive solar coronagraph designed to ultimately fly on the orbiting outpost or as a hosted payload on a commercial satellite.

The super-black carbon-nanotube coating, whose development is six years in the making, is a thin, highly uniform coating of multi-walled nanotubes made of pure carbon about 10,000 times thinner than a strand of human hair. Recently delivered to the International Space Station for testing, the coating is considered especially promising as a technology to reduce stray light, which can overwhelm faint signals that sensitive detectors are supposed to retrieve.

While the coating undergoes testing to determine its robustness in space, a team at NASA's Goddard Space Flight Center in Greenbelt, Maryland, will apply the carbon-nanotube coating to a complex, cylindrically shaped baffle a component that helps reduce stray light in telescopes.

Goddard optical engineer Qian Gong designed the baffle for a compact solar coronagraph that Principal Investigator Nat Gopalswamy is now developing. The goal is build a solar coronagraph that could deploy on the International Space Station or as a hosted payload on a commercial satellite a much-needed capability that could guarantee the continuation of important space weather-related measurements.

The effort will help determine whether the carbon nanotubes are as effective as black paint, the current state-of-the-art technology, for absorbing stray light in complex space instruments and components.

Preventing errant light is an especially tricky challenge for Gopalswamy's team. "We have to have the right optical system and the best baffles going," said Doug Rabin, a Goddard heliophysicist who studies diffraction and stray light in coronagraphs.

The new compact coronagraph designed to reduce the mass, volume, and cost of traditional coronagraphs by about 50 percent will use a single set of lenses, rather than a conventional three-stage system, to image the solar corona, and more particularly, coronal mass ejections (CMEs). These powerful bursts of solar material erupt and hurdle across the solar system, sometimes colliding with Earth's protective magnetosphere and posing significant hazards to spacecraft and astronauts.

"Compact coronagraphs make greater demands on controlling stray light and diffraction," Rabin explained, adding that the corona is a million times fainter than the sun's photosphere. Coating the baffle or occulter with the carbon-nanotube material should improve the component's overall performance by preventing stray light from reaching the focal plane and contaminating measurements.

The project is well timed and much needed, Rabin added.

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NASA Ultra-Black Nano-Coating to Be Applied to 3-D New Solar Coronagraph