BLOG #2 JPL Innovation
Humans have always been intrigued by the stars glowing above
in the heavens throughout our history, but our contemporary interest in faraway
light sources and ‘exoplanets’ consists of a lot more than just primal
fascination. Scientists and researchers at NASA and JPL have been on the hunt
for exoplanets, or planets that orbit around a star much like our own sun and
Earth. The search is for a ‘habitable’ environment, where the atmosphere is not
too hot and not too cold and could sustain water, promoting the growth and
existence of life!
Obviously, there are numerous
technical feats and challenges to overcome in order to locate such planets and
simply photographing them proves to be enough of an obstacle in itself. Originally,
researchers could detect orbiting planets like our own Earth while studying
stars in deep space with space telescopes such as the HUBBLE. The telescope
would have internal adjustments and additions made, such as an internal
coronagraph which consisted of numerous mirrors and filters to help decrease
the amount of flare from starlight in the photographs. This would help the
telescope see the area surrounding the star without the star blowing out the
photograph. This internal technology allowed HUBBLE to thus detect variations
in starlight intensity when a planet would orbit around the star between the
telescope and the star itself, very partially eclipsing the star. Although it
was the only method NASA had to detect exoplanets, it is not the most efficient
process considering the complexity of internal coronagraphs along with the
cost, only complicating the already impressive space telescopes.
The next generation of exoplanet
discovery comes from the research and technical production of JPL’s lead
engineer, Dr. Stuart Shaklan, who is working on a new procedure with JPL’s
engineer team for photographing orbiting planets utilizing what JPL calls a
“Star Shade”. This Star shade is a physically deployable device capable of
eclipsing a star’s intense light emission, allowing high quality, clean
photographs to be taken of a star’s surrounding environment. In theory, the
star shade would be completely collapsible allowing it to fit into a rocket or
telescope, and would then detach and unfold to be the approximate size of a
baseball diamond.
The shade would have miniature thrusters attached along with the ability to communicate with the accompanying telescope in order to maintain proper alignment between the telescope, the star shade, and the star.
The star shade would float approximately 50,000 km away from the telescope in order to achieve a dark enough shadow between the shade and the telescope, allowing flare free photography of the star. Another compelling feature of the star shade itself are its flower petal-like protrusions from its center. These petals serve to greatly decrease the amount of diffraction produced from the starlight behind the shade.
If the star shade were perfectly circular, the light from the star would bend around the round contours of the circular shade and bleed into the photograph, providing unusable results. Thus, a flower petal was devised, muting the amount of diffraction and reducing the amount of stray light entering the imaging sensor.
The shade would have miniature thrusters attached along with the ability to communicate with the accompanying telescope in order to maintain proper alignment between the telescope, the star shade, and the star.
The star shade would float approximately 50,000 km away from the telescope in order to achieve a dark enough shadow between the shade and the telescope, allowing flare free photography of the star. Another compelling feature of the star shade itself are its flower petal-like protrusions from its center. These petals serve to greatly decrease the amount of diffraction produced from the starlight behind the shade.
If the star shade were perfectly circular, the light from the star would bend around the round contours of the circular shade and bleed into the photograph, providing unusable results. Thus, a flower petal was devised, muting the amount of diffraction and reducing the amount of stray light entering the imaging sensor.
References:
https://science.nasa.gov/technology/technology-stories/starshade-enable-first-images-earth-sized-exoplanets
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