SUNSTORM detects huge Easter Sunday flare

On the 17^th April 2022, Easter Sunday, a huge solar flare, so big it reached the rarely seen classification of X-class – the strongest flare type – was detected by the X-ray Flux Monitor on board ESA’s Sunstorm mission.

Sunstorm, a 2-unit CubeSat was funded by Finland in the GSTP Element 3, FLY, while the instrument onboard, called the XFM-CS, was a Finnish GSTP Element 1 activity being flown for in-orbit demonstration purposes. Kuva Space developed and operate the CubeSat, whilst the instrument was developed by an industrial team led by ISAWARE and including ASRO, Oxford Instruments, and Talvioja Consulting.

The flare gave the activity a chance to compare the technologies’ capabilities against the reference models and other similar monitors already in use. The XFM-CS produced a  flux almost identical to the reference models, going some way to proving that small missions are no longer just for demonstrating technology, but can be valuable sources of scientific data in their own right.

Sunstorm is flying a miniaturised version of the X-ray Flux Monitor, that is planned to be used on board the VIGIL and SWFO missions, as part of the in-orbit demonstration process that the technology will work on a longer-term, bigger mission. While there are other x-ray flux monitors currently monitoring the sun, the type of detector which SUNSTORM is equipped with is novel, using new silicon drift diode technology. As this technology has never been used before, the quality of the spectrum an instrument using it would be able to deliver was under discussion. Now it has been shown to resemble the reference flux the XFM-CS can rival monitors twice its size.

Previous X-class flares have been detected by the monitor but this one stands out as the science consortium monitoring the data, ISAWARE in Finland, are able to use it to investigate a new technique using the position and velocity of the satellite in orbit alongside the spectrum to calculate the electron flux and plan to publish these results shortly.

Sunstorm is due to end its operations in august 2022 but in view of the high quality of results the team running the CubeSat are now looking to extend the mission.