Mission OverviewCAPRI-SUN logo showing a sounding rocket arcing towards a solar flare

The High-resolution Coronal Imager (Hi-C) is the main payload of a sounding rocket solar flare campaign (hence the name Hi-C Flare). The goals of the campaign are to acquire an extensive, multi-scale, multi-wavelengh observation of a solar flare and establish the capability of solar pointing missions within the sounding rocket program.

The high CAdence low-energy Passband x-Ray detector with Integrated full-SUN field of view (CAPRI-SUN) instrument is a solar disk integrated soft X-ray sensor designed, fabricated, and tested by SSEL students. CAPRI-SUN will obtain a soft X-ray (SXR) time series at an unprecedented 1 kHz cadence through the duration of solar pointing, providing the first high frequency measurement of flare variability in SXR. 


Hi-C Flare and its companion payloads, including CAPRI-SUN, were launched from the Poker Flatt Missile Range in Alaska on April 17, 2024. The flight was successful with all scientific payloads capturing images of an ongoing solar flare. The sounding rocket was recovered the following day after landing in deep snow.

SSEL students are hard at work trying to recover the data stored internally on CAPRI-SUN. Any data downlinked during flight was found to be unreadable due to a communication line flaw in the harness that connected CAPRI-SUN to the rocket's avionics.

A re-flight of CAPRI-SUN is being considered as another Hi-C Flare campaign is currently in the proposal stage. The SSEL team is evaluating the lessons learned from the first flight of the instrument to assess the feasibility.

Development of the technology used in CAPRI-SUN will continue as it is adapted for use in the BUBO instrument payload for the MUSE satellite being constructed by Lockheed Martin.

CAPRI-SUN delivered and mounted on the bulkhead of the Hi-C Flare rocket

CAPRI-SUN attached to front apeture plate for Hi-C Flare rocket

exploded view of the CAPRI-SUN CAD model with components labeled

Exploded view of the CAPRI-SUN CAD model