The Sun Radio Interferometer Space Experiment (SunRISE): Science Measurements

SunRISE science measurements are driven by background-noise-limited (Galactic and plasma) sensitivity and radio burst localization accuracy to discriminate between candidate particle acceleration regions relative to the structure of a CME. Each of the identical SunRISE smallsats will carry a pair of dipole antenna deca-hectometric (DH) receivers tuned to the 0.1 22.3 MHz band and Global Navigation Satellite Systems (GNSS) receivers for timing and localization. Each spacecraft operates independently, capturing synchronized data using a common GNSS timing reference, and telemeters its data to the ground for processing. The DH dipole antennas (5 m tip-to-tip) will operate as electrically short antennas. Data will be captured in 655 s snapshots every 100 ms and channelized into 4096 frequency sub-bands each 6.1 kHz wide using a poly-phase filter bank. For each snapshot a subset of 64 pre-programmed quiet channels for each of the two DH signal chains, with approximately 10% frequency spacing, is selected for telemetry to ground. Solar radio bursts localization will be provided by the application of Very Long Baseline Interferometric techniques on the radio signals received by each spacecraft with the accuracy necessary to discriminate between hypothesized particle acceleration regions. The SunRISE constellation is maintained in a passive formation contained within a sphere of ~10 km. Weekly orbit correction maneuvers ensure that antenna separations (baselines) of at least 6 km, projected in the direction of the Sun, are available in two orthogonal directions. The GNSS receivers in each spacecraft provide a stream of timing and positioning data. The timing and positing uncertainty for each spacecraft is < 3 ns and < 1 m, respectively, thereby contributing < 10% to the total localization error. The DH and GNSS signals are telemetered to ground where the data is timestamped at JPL and transferred to the science operations center at the University of Michigan. DH radio burst signals associated CMEs with are interferometrically combined to localize their source. Complementary abstracts are presented by J. Kasper, J. Lazio, and A. Hegedus. 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.