ASTERIA (Arcsecond Space Telescope Enabling Research in Astrophysics) is a technology demonstration and opportunistic science mission to conduct astrophysical measurements using a CubeSat. Originally envisioned as a project for training early career scientists and engineers, ASTERIA's technical goal is to achieve arcsecond-level line-of-sight pointing error and highly stable focal plane temperature control. These technologies are important for precision photometry, i.e., the measurement of stellar brightness over time. Precision photometry, in turn, provides a way to study stellar activity, transiting exoplanets, and other astrophysical phenomena.
ASTERIA is a 6U CubeSat (roughly 10 x 20 x 30 cm, 10 kg) that is currently operating in low-Earth orbit. The payload consists of a lens and baffle assembly, a CMOS imager, and a two-axis piezoelectric positioning stage on which the focal plane is mounted. A set of commercial reaction wheels provides coarse attitude control. Fine pointing control is achieved by tracking a set of guide stars on the CMOS sensor and moving the piezoelectric stage to compensate for residual pointing errors. Precision thermal control is achieved by isolating the payload from the spacecraft bus, passively cooling the detector, and using trim heaters to perform small temperature corrections over the course of an observation.
In June 2017, the flight spacecraft was delivered for integration into the Nanoracks CubeSat Deployer. ASTERIA was launched to the International Space Station (ISS) with the SpaceX Falcon-9 Commercial Resupply Services 12 (CRS-12) mission on August 14, 2017. The spacecraft was deployed from the ISS on November 20, 2017 to begin the 90-day ASTERIA technology demonstration mission.
As of February 2018, ASTERIA had met its primary mission requirements by demonstrating pointing stability better than 0.5 arcseconds RMS over 20 minutes and pointing repeatability of 1 milliarcsecond RMS from orbit-to-orbit. The mission also demonstrated thermal stability of +/-0.01 K as measured at a single point on the focal plane.
ASTERIA is currently in an extended mission to search for new exoplanet transits around nearby, bright stars. The extended mission also provides long-term validation of hardware and software for use on future projects.
The ASTERIA project is a collaboration with MIT and is funded at JPL through the Phaeton Program for training early career employees. JPL is responsible for overall project management, systems engineering, spacecraft implementation, integration and test, and mission operations. The main spacecraft subsystem suppliers are Blue Canyon Technologies (Attitude Control Subsystem), Vulcan Wireless (Telecommunications Subsystem), MMA Design LLC (Solar Arrays), GomSpace (Power subsystem and Batteries), Spaceflight Industries (Flight computer), Ecliptic Enterprises (Focal Plane), Physik Instrumente (piezo stage), and Thermotive (thermal hardware). Morehead State University provides spacecraft tracking, telemetry, and control services to the Mission Operations team at JPL. MIT and the University of Bern (Switzerland) perform target selection and analysis of stellar photometry data from ASTERIA.