Experimental exoplanet-hunting CubeSat starts to prove itself in space
A small experimental CubeSat called the Arcsecond Space Telescope Enabling Research in Astrophysics (ASTERIA) has earned recognition for an ability to punch above its own weight. Awarded the Small Satellite Mission of the Year by the Small Satellite Technical Committee of the American Institute of Aeronautics and Astronautics' (AIAA), the bread loaf-sized spacecraft is designed to show that small satellites can hunt for exoplanets just as larger space telescopes like Kepler can, and impressed after "demonstrat[ing] a significant improvement in the capability of small satellites."
The Kepler mission and its successors like TESS have revolutionized our understanding of both other planetary systems and our own Solar System. The thousands of exoplanets confirmed so far provide us with a greater understanding of what kinds of systems are out there, how they formed, and the chances that some of them might harbor life.
The problem is, for all the attempts by space engineers to control costs, space telescopes like Kepler are very expensive and when one malfunctions it's all hands on deck to get it back up and running. For this reason, NASA is interested in spreading the load, looking at the potential to send out a constellation of exoplanet-hunting CubeSats that can take on some of the duties of their larger conventional counterparts.
Built in collaboration between NASA's Jet Propulsion Laboratory and MIT as part of a program to train early career employees, ASTERIA is a CubeSat measuring 10 x 20 x 30 cm (3.9 x 7.8 x 11.8 in), not counting the two deployable solar panels that power it. Inside, there is a lens and a baffle assembly along with a CMOS imager, and a focal plane mounted on a two-axis piezoelectric positioning stage. In addition, there is a set of reaction wheels for attitude control backed up with star trackers for fine tuning, and a thermal control system to keep the electronics and optics at an even temperature within one degree Kelvin.
It was sent to the International Space Station (ISS) aboard a SpaceX Dragon unmanned cargo ship on the CRS-12 mission on August 14, 2017. It was then deployed from the station in November 2017 and went into low-Earth orbit for a 90-day demonstration mission to show that ASTERIA could point at a spot in the sky with a stability over 0.5 arcseconds Root Mean Square (RMS) for 20 minutes, and do so with a repeatability of one milliarcsecond RMS from orbit-to-orbit.
ASTERIA is currently on an extended mission to determine the long-term viability of its hardware and software as it searches for signs of exoplanets orbiting nearby bright stars.