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MinXSS Science Nugget 9

MinXSS-1 Data consistency with Hinode XRT, GOES XRS, and SDO AIA Observations

2018 April 23

Chris Moore and the MinXSS Science Team

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSat soft X-ray (SXR) spectra measured by the X-ray spectrometer (X123) is ideal for analyzing plasma properties above 1 MK (Woods et al. 2017). MinXSS-1 X123 can conduct solar spectral measurements from 0.8 – ~12 keV with an effective spectral resolution of roughly ~0.24 keV near 5.9 keV (Moore et al. 2018). These spectral measurements display important variations in the solar flux from quiescent conditions with minimal active regions, to active region dominated emission, to flares.

The first of the twin satellites, MinXSS-1, was ferried to the International Space Station (ISS) from the Kennedy Space Center on 6 December 2015 and deployed from the ISS on 16 May 2016 to a low Earth orbit (LEO) with an initial altitude of ≈ 402 km. MinXSS-1 performed science operations from June 9, 2016 to April 23, 2017. The MinXSS-1 inferred spectral photon flux correlate well with and are consistent with measurements from other solar X-ray observatories. These include the Geostationary Operational Environmental Satellites (GOES) X-ray Sensor (XRS) energy fluxes between 0.1 – 0.8 nm (1.55 – 12.4 keV) (see Nugget 008), Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) (Lin et al. 2002) (see Nugget 006), and from the Hinode X-ray Telescope (Golub et al. 2007) (this Nugget, 009).

Figure 1 is a video comparing the aforementioned data sets along with images from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) 171 angstrom set. The data are the closets in time with the Hinode XRT Be-thin full Sun synoptic program (roughly two images per day) over the MinXSS-1 mission. The MinXSS-1 time series of energy flux for photon energies greater than 1 keV normalized to 1 AU is plotted in the top right panel. Aside from noisy MinXSS-1 data points, the data trend well with the XRT Be-thin (scaled for display purposes) DN s-1 sr-1, GOES 0.1 – 0.8 nm flux (W m2), and the subtle variations in the AIA 171 data (DN s-1 sr-1, scaled for display purposes). The MinXSS-1 photon flux is in the top right plot, AIA 171 images in the bottom left plot, and the bottom right plot contains the XRT Be-thin images.

The MinXSS-1 Level1 data product is continuously being modified by the MinXSS Science Team to deliver the highest quality data set to the scientific community. We expect better measurements from the second CubeSat, called MinXSS-2. MinXSS-2 is scheduled to launch in late 2018 for up to 4 years.



  1. Woods, T. N., A. Caspi, P. C. Chamberlin, A. Jones, R. Kohnert, J. P. Mason, C. S. Moore, S. Palo, C. Rouleau, S. C. Solomon, J. Machol, and R. Viereck, New Solar Irradiance Measurements from the Miniature X-ray Solar Spectrometer CubeSat, Astrophys. J., 835, 122, doi:10.3847/1538-4357/835/2/122, 2017.
  2. Moore, C. S., Caspi, A., Woods, T. N., Chamberlin, P. C., Dennis, B. C., Jones, A., Mason, J. P., Schwartz, R., Tolbert, K. A., Solar Physics, “The Instruments of the Miniature X-ray Solar Spectrometer (MinXSS) CubeSats”, Sol Phys (2018) 293: 21.
  3. Lin, R. P. Dennis, B. R. Hurford, G. J. Smith, D. M., et al., “The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI)”, 2002SoPh..210….3L
  4. Golub, L.., Deluca, E., Austin, G., Bookbinder, J., Caldwell, D., Cheimets, P., Cirtain, J., Cosmo, M., Reid, P., Sette, A., Weber, M., Sakao, T., Kano, R., Shibasaki, K., Hara, H., et al., “The X-Ray Telescope (XRT) for the Hinode Mission”, Solar Physics, Volume 243, Issue 1, pp.63-86, 2007