NanoRacks-Miniature X-ray Solar Spectrometer CubeSat (NanoRacks-MinXSS) - 09.26.18

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Solar variability energy is much more for x-ray radiation than visible light; the sun constantly streams X-rays and other invisible particles toward Earth, which can heat up the planet’s atmosphere. The University of Colorado Laboratory for Atmospheric Space Physics (LASP) developed the NanoRacks-Miniature X-ray Solar Spectrometer CubeSat (NanoRacks-MinXSS) to better understand solar X-ray energy and how it affects the layers of Earth’s upper atmosphere. The small student-designed satellite launches from the International Space Station via the NanoRacks CubeSat Deployer (NRCSD) and measures variations in solar X-ray activity, providing new insight into solar flares, the solar corona and other solar phenomena.
Science Results for Everyone
Information Pending

The following content was provided by James Mason, and is maintained in a database by the ISS Program Science Office.
Experiment Details


Principal Investigator(s)
Thomas Woods, Ph.D., Laboratory for Atmospheric and Space Physics, Boulder, CO, United States

Amir Caspi, Ph.D., Southwest Research Institute , Boulder, CO, United States
Philip Chamberlin, Ph.D., NASA Goddard Space Flight Center, Greenbelt, MD, United States
Andrew Jones, Ph.D., Laboratory for Atmopsheric and Space Physics, Boulder, CO, United States
Rick Kohnert, M.S., Laboratory for Atmospheric and Space Physics, Boulder, CO, United States
Xinlin Li, Ph.D., Laboratory for Atmospheric and Space Physics, Boulder, CO, United States
Scott Palo, Ph.D., University of Colorado, Boulder, CO, United States
Stanley Solomon, Ph.D., High Altitude Observatory, Boulder, CO, United States

University of Colorado, Laboratory for Atmospheric and Space Physics (LASP), Boulder, CO, United States

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Technology Demonstration Office (TDO)

Research Benefits
Earth Benefits, Scientific Discovery

ISS Expedition Duration
September 2015 - March 2016; March 2016 - September 2016

Expeditions Assigned

Previous Missions
Information Pending

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Experiment Description

Research Overview

  • The NanoRacks-Miniature X-ray Solar Spectrometer CubeSat (NanoRacks-MinXSS) measures the solar soft X-ray spectrum from 0.5-30 keV (0.04-2.5 nm) with 0.15 keV energy resolution.
  • This part of the solar X-ray spectrum has never been observed with simultaneously as wide a range and as high a spectral resolution as NanoRacks-MinXSS.
  • This part of the solar X-ray spectrum is where we expect to see the greatest enhancements during solar flares.
  • The NanoRacks-MinXSS solar X-ray measurements bridge hard X-ray spectral measurements by the Reuven Ramaty High Energy Solar Spectroscope Imager (RHESSI) and extreme ultraviolet spectral measurements by the Solar Dynamics Observatory (SDO).
  • Solar soft X-rays are an extremely important input to the Earth’s upper atmosphere, dramatically affecting the ionization, heating, and photochemistry there.
  • Existing models of Earth’s upper atmosphere have limited accuracy due to the lack of knowledge of the solar X-ray energy distribution – use of NanoRacks-MinXSS solar X-ray spectra in these models is expected to resolve this issue.


The science objective of the NanoRacks-Miniature X-ray Solar Spectrometer CubeSat (NanoRacks-MinXSS) is to better understand the solar irradiance energy distribution of solar soft X-ray (SXR) emission and its impact on Earth’s ionosphere, thermosphere, and mesosphere (ITM). Energy from SXR radiation is deposited mostly in the ionospheric E-region, from approximately 80 to 150 km, but the altitude is strongly dependent on the SXR spectrum because of the steep slope and structure of the photoionization cross sections of atmospheric gases in this wavelength range. The NanoRacks-MinXSS solar X-ray spectra are used to understand better the influence of the solar X-ray variations in ionizing and heating Earth’s upper atmosphere. In addition, the NanoRacks-MinXSS solar X-ray measurements provide new insight into the energetics of solar flares and the composition of the highly-variable solar corona where flares originate.
The hardware for NanoRacks-MinXSS is a mixture of custom development and commercial products. University of Colorado (CU) students and their mentors custom designed and developed the structural bus, electronics motherboard, electrical power system, solar panels, command and data handling board, fine sun position sensor, and broadband X-ray photometer. The flight items purchased include the high-precision 3-axis attitude determination and control system from Blue Canyon Technologies, UHF radio from AstroDev, high-efficiency triple-junction solar cells from Azurspace, and x-ray spectrometer from Amptek.

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Space Applications
The NanoRacks-MinXSS CubeSat studies high-energy particles streaming from the sun, which helps scientists understand phenomena like solar flares, the composition of the sun’s atmosphere and how it is heated, and how X-rays energize Earth’s atmosphere. New insight into solar physics could help scientists predict solar storms and provide advance warning to crew members in orbit who would need to take shelter. In addition, the NanoRacks-MinXSS CubeSat is the first to fly a high-precision satellite orientation and control system developed by a small startup company called Blue Canyon Technologies. If effective, the control system could be widely used in future CubeSat missions.

Earth Applications
Violent storms of energy streaming from the sun can disrupt Earth’s atmosphere and spacecraft orbiting the planet, disabling satellites and causing power outages. But scientists do not fully understand solar flares and other space weather phenomena. This investigation improves understanding of X-ray activity in the sun, which improves scientists’ ability to forecast solar storms and mitigate damage, benefiting people on Earth. In addition, students at the University of Colorado designed and built the satellite and instruments, gaining real-world experience in science and engineering and connecting them to the space program.

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Operational Requirements and Protocols

Not applicable. 

NanoRacks CubeSats are delivered to the International Space Station (ISS) already integrated within a NanoRacks CubeSat Deployer (NRCSD). A crew member transfers each NRCSD from the launch vehicle to the JEM. Visual inspection for damage to each NRCSD is performed. When CubeSat deployment operations begin, the NRCSDs are unpacked, mounted on the JAXA Multi-Purpose Experiment Platform (MPEP) and placed on the JEM airlock slide table for transfer outside the ISS. A crew member operates the JEM Remote Manipulating System (JRMS) – to grapple and position for deployment. CubeSats are deployed when JAXA ground controllers command a specific NRCSD.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Related Websites
MinXSS CubeSat

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NanoRacks-MinXSS is a 3-Unit (3U) CubeSat with deployable solar arrays and a tape-measure antenna for UHF communication. Image courtesy of University of Colorado and NASA.

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NASA Administrator Charles Bolden (left) visits with NanoRacks-MinXSS students: Sid Naik, Bena Mero, James Mason, Sindhura Bandapalle, and Rohit Kandurwar (Spring 2014). Image courtesy of University of Colorado and NASA.

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image With intense concentration, NanoRacks-MinXSS students Jake Mashburn and Bena Mero integrate solar cells onto a custom solar panel (Spring 2014). Image courtesy University of Colorado and NASA.
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The NanoRacks-MinXSS CubeSat is tested on an air-bearing table to verify the Blue Canyon Technologies (BCT) attitude control system performance. From left to right are Matt Carton (former NanoRacks-MinXSS student, now working at BCT), Rick Kohnert (NanoRacks-MinXSS system engineer who built the air-bearing table), Gregg Allison (NanoRacks-MinXSS flight software programmer), and Tom Woods (NanoRacks-MinXSS principal investigator). Image courtesy University of Colorado and NASA.

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