FOXSI-5: A Rocket Re-flight for High Resolution Focused X-ray Observations of the Sun

We propose a reflight of the Focusing Optics X-ray Solar Imager (FOXSI-5) experiment in a sounding rocket solar flare campaign to investigate particle acceleration and energy release in a large solar flare. A sounding rocket campaign, including triggered observations of solar flares, is a new capability for NASA. Before the development of the flare campaign concept, sounding rocket experiments had limited launch windows and could only observe quiescent conditions (or small microflares if they occurred serendipitously). The first such campaign will be carried out in March/April 2024 to trigger a launch on a medium-to-large solar flare and observe that flare while it is still in progress. To enable this type of opportunistic signal-driven launch, a broad team of solar scientists has banded together to determine the best way to identify that a flare is in progress and the likelihood that early flare signatures indicate a bright and long-lasting flare. Three experiments will fly in the first campaign, including FOXSI-4; that flight is already funded and planned. FOXSI, an X-ray experiment, investigates solar flare particle acceleration and energy release with significantly higher sensitivity than past instruments, using direct-focusing X-ray telescopes and photon-counting detectors. While the first three FOXSI flights proved the method's value in measuring the Sun under quiescent conditions and small microflares, FOXSI-4 will be the first to employ its technology for its primary objective: to observe particle acceleration in a medium-to-large flare. However, observing a single flare with FOXSI-4 will only scratch the surface of what can be learned about flare energy release using this high-sensitivity instrument. Therefore, we propose another flight (FOXSI-5) to double the scientific gain from this advanced instrument in this new flare-triggered observation platform. The scientific promise of this flare campaign capability is revolutionary. For the first time, investigations in solar flare energy release, particle acceleration, and flare heating can be investigated via sounding rockets. It is imperative to conduct more solar flare sounding rocket campaigns, which must be done while solar activity is still high. FOXSI has a mature technology developed through three flights, with a fourth one soon to come. It is an ideal instrument to fly on a new flare campaign, as it is a low-risk, well-understood instrument that can be turned around quickly from its prior flight. In order to ensure that fast turnaround (and thus to re-launch while the solar cycle is still high), we do not perform any hardware development for FOXSI-5; it is a reflight of the FOXSI-4 experiment. In this proposal, we describe the science of FOXSI, its hardware, and what we will gain with a second flare campaign.

This is a mature technology (TRL 7+) — the realistic path in is usually NASA's Technology Transfer Program: licensing an existing NASA patent, or a Space Act Agreement to use NASA facilities/expertise directly. NASA also runs a startup licensing program with no upfront fee for companies formed to commercialize a specific NASA technology.

None of these are guaranteed paths for this specific project — TechPort itself doesn't have an "apply" button. Reaching out to the contact(s) above with a specific question is usually the fastest way to find out what's actually open.