The Sun Radio Interferometer Space Experiment mission is creating the first low radio frequency interferometer in space to better understand how the Sun generates and releases solar bursts. The mission uses a space-based array, composed of six small satellites, or CubeSats, flying in supersynchronous geosynchronous Earth orbit (GEO) within 10 km of each other. The array will image the sun and thus give key information on particle acceleration mechanisms associated with coronal mass ejections.
NASA released an Announcement of Opportunity in 2016, after which the Principal Investigator and his team submitted the proposal for SunRISE. The mission was selected to begin the Phase A study in 2017 and is now in Phase B, which was initiated in June of 2020. The spacecraft are expected to launch in August 2023.
The core science operations occur after launch during Phases D and E and are split into several smaller phases. The six satellites will be deployed from the host spacecraft, maneuvered into their constellation formation, and prepared for science operations. During Phase E, the spacecraft will work in concert in repeated weekly operational patterns.
As the brightest object in the solar system, the Sun is, at large, unbeknown to us. Throughout the course of recorded history, the Sun has had a remarkable amount of illustrated accounts, but the physics behind those observations have been shrouded in mystery. One aspect of the Sun has been exceptionally crucial to us as we enter the age of telecommunication. It’s been cited that periodical bursts of charged particles could wreak unprecedented havocs to everything that runs on electricity. It is with great anticipation and hope that the SunRISE mission will leverage a well-established remote sensing technique, with a six-satellite formation in a supersynchronous orbit, to create a long-baseline interferometer to discriminate competing hypotheses for the generation of Solar Energetic Particles (SEPs) and its relation to Coronal Mass Ejections (CMEs). In particular, one major scientific goal is to associate and correlate Type II radio emissions to said SEPs. Another goal is to reconstruct magnetic field lines associated with Type III radio burst, which helps discriminate competing hypotheses for the variable magnetic connection between active regions and the inner heliosphere. In summary, this mission will help us understand how SEPs accelerate and the correlations between Type II radio bursts and the formation of CMEs.
Technical Approach and Design
SunRISE has three main mission features which are utilized to conduct aperture synthesis. This process combines the observations of smaller antennas which reflect frequency coverage of a larger antenna. The position of the spacecraft does not need to be controlled as long as we know the position accuracy to be within 1 meter. Each spacecraft measures the radio emissions between 0.1 Mhz and 25 Mhz, which are then related to a GNSS satellite (Global Navigation Satellite System). The GNSS signals are used to synchronize the data from all SunRISE spacecraft which means there is no need for communication between the spacecraft, thus each individual spacecraft operate independently. The individual data are combined on the ground to form the SunRISE aperture synthesis. The spacecraft for SunRise will be designed by the Space Dynamic Laboratory of the Utah State University Research Foundation. The hardware and software used onboard SunRise has been used before in space. SunRise will integrate the components into a small satellite design which also incorporates the data and GNSS receiver. The integrated receiver is housed inside the science payload which also includes the SunRise dual dipole antenna. The radio emission data is processed into a frequency domain which is then transmitted to a GNSS satellite for post-processing on the ground. The position and time of the solar radio bursts can be calculated using the data received from the GNSS satellites during post-processing.
With the goal of training the next generation leaders in Heliophysics, SunRISE has partnered with the Multidisciplinary Design Program (MDP) at the University of Michigan. Undergraduate students are designing, constructing, and testing a ground radio prototype and developing a data pipeline to support SunRISE observations. Learn more about our student team here.