The role of timing and location knowledge in enabling the SunRISE mission

The Sun Radio Interferometer Space Experiment (SunRISE) is a NASA Explorer mission in Phase B with launch in 2023. SunRISE will be the first low radio frequency array in space, imaging and tracking the motion of solar radio bursts in order to understand how particles are accelerated and transported from the Sun into space by flares and coronal mass ejections. SunRISE is a constellation of six small satellites flying in a loose formation in a 10 km distribution just above geosynchronous orbit, each of which is equipped with a low frequency antenna system that coherently captures radio emission from 0.1-20 MHz. The critical technological challenges for SunRISE were synchronizing data acquisition across the spacecraft, and determining the physical separations of the spacecraft with the precision needed to form interferometric images of the sky. These challenges were met through the real time processing of GNSS signals on each spacecraft, allowing them to operate independently, permitting a reduction in telemetry to the ground by five orders of magnitude. The implementation and status of SunRISE will be reviewed with a focus on enabling constellation mission architectures.