FOXSI-4: The high resolution focusing X-ray rocket payload to observe a solar flare

Juan Camilo Buitrago-Casas, Juliana Vievering, Sophie Musset, Lindsay Glesener, P. S. Athiray, Wayne Baumgartner, Stephen Bongiorno, Patrick Champey, Steven Christe, Sasha Courtade, Gregory Dalton, Jessie Duncan, Kelsey Gilchrist, Shin Nosuke Ishikawa, Christine Jhabvala, Hunter Kanniainen, Sam Krucker, Kyle Gregory, Juan Carlos Martinez Oliveros, Jeff McCrackenIkuyuki Mitsuishi, Noriyuki Narukage, Athanasios Pantazides, Eliad Peretz, Savannah Perez-Piel, Aruna Ramanayaka, Brian Ramsey, Danny Ryan, Sabrina Savage, Tadayuki Takahashi, Shin Watanabe, Amy Winebarger, Yixian Zhang

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations


The FOXSI-4 sounding rocket will fly a significantly upgraded instrument in NASAs first solar are campaign. It will deploy direct X-ray focusing optics which have revolutionized our understanding of astrophysical phenomena. For example, they have allowed NuSTAR to provide X-ray imaging and IXPE (scheduled for launch in 2021) to provide X-ray polarization observations with detectors with higher photon rate capability and greater sensitivity than their predecessors. The FOXSI sounding rocket is the first solar dedicated mission using this method and has demonstrated high sensitivity and improved imaging dynamic range with its three successful flights. Although the building blocks are already in place for a FOXSI satellite instrument, further advances are needed to equip the next generation of solar X-ray explorers. FOXSI-4 will develop and implement higher angular resolution optics/detector pairs to investigate fine spatial structures (both bright and faint) in a solar are. FOXSI-4 will use highly polished electroformed Wolter-I mirrors fabricated at the NASA/Marshall Space Flight Center (MSFC), together with finely pixelated Si CMOS sensors and fine-pitch CdTe strip detectors provided by a collaboration with institutes in Japan. FOXSI-4 will also implement a set of novel perforated attenuators that will enable both the low and high energy spectral components to be observed simultaneously in each pixel, even at the high rates expected from a medium (or large) size solar are. The campaign will take place during one of the Parker Solar Probe (PSP) perihelia, allowing coordination between this spacecraft and other instruments which observe the Sun at different wavelengths.

Original languageEnglish (US)
Title of host publicationUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXII
EditorsOswald H. Siegmund
ISBN (Electronic)9781510644809
StatePublished - 2021
EventUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXII 2021 - San Diego, United States
Duration: Aug 1 2021Aug 5 2021

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceUV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXII 2021
Country/TerritoryUnited States
CitySan Diego

Bibliographical note

Funding Information:
The first author of this paper is funded by the NASA FINESST grant 80NSSC19K1438. The FOXSI sounding rocket experiment is funded by NASA grants 80NSSC21K0030, 80NSSC17K0430, NNX08AH42G, NNX11AB75G, and NNX16AL60G. The Univeristy of Minnesota team is supported by an NSF Faculty Development Grant (AGS-1429512), an NSF CAREER award (NSF-AGS-1752268), the SolFER DRIVE center (80NSSC20K0627), and NASA Headquarters under the NASA Earth and Space Science Fellowship Program (80NSSC17K0430).

Funding Information:
Work at UC Berkeley in the Timepix3 detector development is supported by NASA Grant NNH17ZDA001N-HTIDS.

Funding Information:
This work was supported by JSPS KAKENHI Grant JP16H02170, JP15H03647, JP21540251.

Funding Information:
This work was also supported by JSPS KAKENHI Grant Numbers JP17H04832, JP16H02170, JP16H03966, JP24244021, JP20244017, and World Premier International Research Center Initiative (WPI), MEXT, Japan.

Publisher Copyright:
© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.


  • The Sun, high-energy, X-rays, sounding rocket, X-ray focusing optics


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