Advanced science.  Applied technology.


Risk Mitigation of the Suprathermal Ion Spectrograph, 15-R6014

Principal Investigators
Mihir Desai
Don George
Michael Epperly
Inclusive Dates 
12/16/19 to 08/03/20


Southwest Research Institute leads a CubeSat mission to study Solar Particles: CuSP, in partnership with NASA’s Goddard Space Flight Center and the Jet Propulsion Laboratory. CuSP is a grant funded by NASA to design, develop, and integrate a 6U (volume ~30×20×10 cm, mass ~14 kg) CubeSat with three complementary miniaturized sensors to address the following primary science objectives:

  • Study the sources and acceleration mechanisms of solar and interplanetary (IP) particles in heliospheric orbit.
  • Support space weather research by determining proton radiation levels during Solar Energetic Particle (SEP) events.
  • Identify suprathermal (ST) properties that could help predict geomagnetic storms.

CuSP’s technical objective is to increase the technological readiness level (TRL) of our novel in situ ST ion spectrograph (SIS) instrument concept so that it can be proposed and flown with significantly reduced risk and cost on future heliophysics missions. SIS will measure angular distributions and energy spectra of ~3–70 keV/q ions. SIS utilizes a novel electrostatic analyzer (ESA) that was developed and tested using IR&D funding and a NASA research grant. Technical problems were encountered during the development and testing of the SIS flight model (FM) and, while SIS worked, some areas needed improvements to achieve the predicted performance and better margins on the technical challenges.


We divided the project into three objectives:

  1. Perform review to identify all remaining risks.
  2. Implement mitigation strategies for top priority risks.
  3. Test and verify instrument.


This project has significantly reduced the risks associated with SIS. A technical review was conducted at the beginning of the project to identify the known risks and sort them according to an assigned priority. We addressed all the risks that were evaluated as critical for success. While addressing the other risks would have resulted in a better instrument, it was not necessary for success and the mitigations required more funding and time than available. Specifically, we mitigated the following risks:

  • We reduced electronics noise and UV-induced noise and thus increased the signal-to-noise ratio.
  • We implemented a way to remove heat from the power supplies and thus increased operating time.
  • We tested the high electric field (9 kV/mm) more than ~10% above the expected maximum and for longer (> 1 hour) than nominal (1 minute every five minutes).