Extended Mission Technology Demonstrations Using The Asteria Spacecraft

ASTERIA (Arcsecond Space Telescope Enabling Research In Astrophysics) is a CubeSat space telescope currently operating in low-Earth orbit. It is expected to remain in orbit at least through October 2019. Developed as a technology demonstration mission under the Jet Propulsion Laboratory Phaeton Program for training early-career engineers, ASTERIA has achieved sub-arcsecond pointing stability and milliKelvin thermal stability over 20-minute observations. These capabilities-unprecedented in a CubeSat platform-have enabled photometric precision better than 1000 parts per million per minute (0.1%/min) while observing nearby bright stars (apparent visual magnitude mag(V) < 6).Following the second extended mission, we are now using the spacecraft in its third extension as a platform to demonstrate additional capabilities as well as continue science observations. This project will perform the following four well-focused activities that will raise the technology readiness of key spacecraft technologies.1. Shift the paradigm to operate spacecraft from openloop commanding to closed-loop command execution: We will introduce "task networks" (tasknets) which allow simpler commanding and more robust onboard execution.2. Demonstrate onboard orbit determination in Low Earth Orbit (LEO) using autonomous navigation (Autonav) without the Global Positioning System (GPS): This activity will demonstrate a fully independent means of spacecraft orbit determination for Earth orbiters using only passive imaging.3. Collect data on ASTERIA that will feed into future missions by characterizing the spacecraft pointing jitter as a function of target brightness, reaction wheel speed, controller gain, and number of guide stars.4. Perform ASTERIA extended mission science: ASTERIA has demonstrated unprecedented photometric precision for a CubeSat mission. The spacecraft is uniquely suited to perform long-term monitoring of stars such as alpha Centauri for small transiting planets. The discovery of a transiting Earth-sized planet around alpha Cen A and/or B would be of the highest scientific value as such a planet would be our closest exoplanetary neighbor orbiting a Sun-like star.These demonstrations will provide in-flight testing of new autonomy technologies, maximize the scientific potential of this operational spacecraft, and provide additional characterization of hardware for future small satellite missions using similar subsystems.