NASA Looks to Giant ‘Starshade’ to Expand Search for Exoplanets

NASA’s “Starshade” craft uses technology that can block starlight to help scientists reveal the presence of planets orbiting a star. (NASA / JPL-Caltech)

PASADENA, Calif. (CN) – The quest to find exoplanets – Earth-like objects orbiting distant stars in our universe – will get a boost from a flower-like spacecraft with metallic petals to block starlight long enough for telescopes to view distant objects like never before, NASA said Tuesday.

The universe may be teeming with trillions of exoplanets millions of light-years from Earth, but finding them isn’t easy since they don’t produce their own light and are usually faint in comparison to the bright stars they orbit.

To get around this challenge, NASA engineers at the Jet Propulsion Laboratory in Pasadena, California, have designed “starshade” technology to block starlight.

A future starshade mission would involve two spacecraft, one a telescope on the hunt for exoplanets orbiting stars and the other flying an enormous, flat shade nearly 25,000 miles in front of the telescope.

The shade’s “petals” would blossom like a flower to block starlight, allowing the telescope to get a clearer view of objects orbiting the star.

But NASA engineer Michael Bottom said in a statement that the process will only work if the two spacecraft align – despite the vast gap between them – to within 3 feet.

“If the starshade were scaled down to the size of a drink coaster, the telescope would be the size of a pencil eraser and they’d be separated by about 60 miles,” Bottom said. “They’re both experiencing these little tugs and nudges from gravity and other forces, and over that distance we’re trying to keep them both precisely aligned to within about 2 millimeters.”

Bottom found two spacecraft can be aligned using automated sensors and thruster controls, even meeting the alignment demands of a larger starshade positioned up to 46,000 miles from the telescope.

But any movement out of alignment would leak starlight past the shade and overexpose the telescope, ruining any view of an exoplanet.

Although starshades – a technology first proposed in the 1960s, four decades before the first exoplanet was discovered – have never flown in space and have not been approved for flight, they could join a mission to space in the late 2020s, NASA said Tuesday.

The only exoplanets viewed through a telescope or by direct imaging, as it’s known, tend to be young gas giants orbiting far away from parent stars, NASA said, and are typically found when they happen to pass by a dimming star.

NASA has confirmed the discovery of nearly 4,000 exoplanets – also called “extrasolar” planets because they lie outside of our solar system – but has yet to find any like Earth.

The agency has detected another 3,000 “candidate” objects in space that require further observations to determine whether or not they are exoplanets.

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