Serendipitous Stellar Occultations from Cubesats
The Flicker cubesat mission proposal was developed for the first NASA SIMPLEx call for planetary science cubesat missions. It would be an innovative 6U Earth-orbiting observatory carrying three telescopes with ultra-fast wide-field cameras to catch the momentary flicker of light when a distant object in the Kuiper Belt briefly occults a background star.
Though only carrying telescopes the size of coffee mugs, Flicker would test predictions of competing models of planet formation by collecting a well-characterized census of small (diameter less than 1 km) objects residing in the outer fringes of the solar system beyond Neptune.
Trans-Neptunian Objects this small are currently undetectable in reflected light for all astronomical facilities. However, these otherwise-invisible objects can be detected indirectly by their effect on background stars during serendipitous stellar occultations. These occultation events (where a trans-Neptunian Object passes in front of a background star from the perspective of an observer) are rare, requiring that many stars be monitored simultaneously to make their detection likely. Occultation events are also extremely short in duration (typically about 0.2 seconds) and diffraction-dominated (leading to complex occultation signals), requiring that these stars’ brightnesses be measured many tens of times per second to resolve the events. Ground-based observatories are hampered by insidious noise sources that mimic occultation signals; these noise sources are eliminated in space.
Flicker would be the first dedicated space-based occultation observatory. By combining data from its three co-aligned telescopes, Flicker would carry more light-gathering area in its 6U form factor than any existing spacecraft in its class, delivering high-quality (SNR>15), high-speed (40 Hz) photometry for several hundred stars simultaneously. Flicker was also designed to downlink each and every stellar lightcurve in its entirety, enabling detailed audits of its sensitivity and false positive rate. With these capabilities and a baseline one-year mission, Flicker would far exceed any existing surveys’ capability of detecting and characterizing the population of small trans-Neptunian Objects.