The ASTERIA CubeSat, launched from the International Space Station into low-Earth orbit in 2017, has become the smallest satellite to successfully detect an exoplanet.
And that's thanks to the scientists and engineers who managed to squeeze hardware capable of measuring tiny fluctuations of light from a star down to a CubeSat form factor. The 10cm × 20cm × 30cm bird managed to pick up 55 Cancri e, some 40 light years away and a celestial body that was known though had never been detected by such relatively lightweight kit before.
"Detecting this exoplanet is exciting, because it shows how these new technologies come together in a real application," said Vanessa Bailey, the principal investigator for ASTERIA's exoplanet science team at NASA’s Jet Propulsion Laboratory, today.
ASTERIA uses the popular transit method to detect telltale signs of exoplanets, just like larger advanced observatories such as ESA’s CHEOPS, though it operated at a much smaller scale. It looked for periodic dips in the star 55 Cancri A’s brightness as 55 Cancri e crossed in front of the sun and temporarily dimmed its light.
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Fine control helped keep the nifty CubeSat steady so it could focus its instruments on the far-away star system. Any wobbles or vibrations produce unwanted noisy effects in the data, making it more difficult to detect alien Earth-sized worlds.
Infrared light was measured using a 15cm-long telescope, and detected using a CMOS sensor that did not require a cooling system that a cold-operating CCD sensor would require.
"We went after a hard target with a small telescope that was not even optimized to make science detections - and we got it, even if just barely," said Mary Knapp, the ASTERIA project scientist at MIT's Haystack Observatory.
The results have been accepted for publication at the Astrophysical Journal. Here’s the free preprint version. "I think this paper validates the concept that motivated the ASTERIA mission: that small spacecraft can contribute something to astrophysics and astronomy," Knapp added.
ASTERIA is now defunct after mission control lost communication with the small satellite in April this year – though not before its sensor data was received. ®