Implementation of the Sun Radio Interferometer Space Experiment (SunRISE) Mission Concept

The Sun Radio Interferometer Space Experiment (SunRISE) would provide an entirely new view on particle acceleration and transport in the heliosphere by obtaining spatially and temporally resolved observations of Decametric-Hectometric (DH, < 15 MHz) Type II and Type III radio bursts.

In order to obtain the required angular resolution, SunRISE would be a free-flying interferometer. Building on more than 50 years of experience from ground-based very long baseline interferometry (VLBI), SunRISE would fly six small spacecraft in a supersynchronous geosynchronous orbit (GEO) in a passive formation. Their orbits are designed to keep them within approximately 6 km of each other. A space-based interferometer is required because most of the DH band does not penetrate the Earth's ionosphere, due to ionospheric absorption.

Each 6U spacecraft would carry only a single science radio designed to operate in the DH band. The radio would form spectra on-board, with pre-selected sub-bands identified for downlink. This science payload radio would be integrated into a Global Positioning System (GPS) receiver, allowing precise time to be measured on board the spacecraft as well. The spacecraft would be independent of each other, as is the practice for ground-based VLBI arrays.

On a regular basis, both science data and GPS timing would be downlinked. NASA's Deep Space Network antennas would be used for the downlink, with an efficient multiple spacecraft per aperture (MSPA) mode enabling the data from three spacecraft to be downlinked simultaneously. After orbit determination, the interferometric data processing would form images of Type II and Type III solar radio bursts and identify the locations of radio emission relative to the structures of CMEs.

SunRISE would leverage advances in software-defined radios, GPS navigation and timing, and small spacecraft technologies that have been demonstrated over the past few years. An Extended Phase A study of the SunRISE mission concept is scheduled to be completed in 2019 September.

Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Some of the information presented is pre-decisional and for planning and discussion purposes only.