CubeSat for Solar Particles

Lore & Background

CuSP carried three scientific instruments: the Suprathermal Ion Spectrograph (SIS) built by SwRI to detect low-energy solar energetic particles; the Miniaturized Electron and Proton Telescope (MERiT) built by NASA's Goddard Space Flight Center to count high-energy solar energetic particles; and the Vector Helium Magnetometer (VHM) built by NASA's Jet Propulsion Laboratory to measure magnetic field strength and direction. The spacecraft used a passive attitude control system with magnetorquers and a reaction wheel, and had no propulsion system for orbit maneuvers. Its bus included components from SwRI, Clyde-Space AAC, Blue Canyon Technologies, and NASA centers.

Reader's Guide

CuSP's significance lies in its demonstration of using low-cost CubeSats for deep-space space weather monitoring. Although the mission ended prematurely after about an hour of successful operation, it validated the concept of deploying small, standardized spacecraft as secondary payloads on large launch vehicles like the SLS. The loss of contact highlighted the challenges of operating CubeSats beyond Earth orbit, where communication and anomaly resolution are limited. The mission's instruments—SIS, MERiT, and VHM—were designed to measure solar energetic particles and magnetic fields, key data for understanding space weather that affects Earth's technology. CuSP was part of a broader effort to create a distributed network of space weather stations, which would require many instruments scattered millions of miles apart. While the spacecraft failed to return long-term data, its engineering and operational lessons inform future low-cost heliophysics missions. The investigation into telemetry and temperature anomalies provided valuable troubleshooting experience for similar projects.

Did You Know?

• CuSP was a 6U CubeSat launched on the maiden flight of the Space Launch System as part of Artemis 1.
• CuSP was designed to operate for only a few hours after deployment into heliocentric orbit, not as a long-term solar mission.
• Contact with CuSP was lost approximately 1 hour and 15 minutes after deployment, ending the mission prematurely.
• The exact cause of the loss of contact was never definitively determined by NASA or SwRI, and reports of a telemetry failure remain unconfirmed.

Mission Design & Scientific Objectives

CuSP was conceived as a 6U CubeSat to orbit the Sun and study dynamic particles and magnetic fields. The broader goal was to measure space weather phenomena that can disrupt radio communications, interfere with satellite electronics, and induce electric currents in terrestrial power grids. Building a full network of space weather stations scattered millions of miles apart is prohibitively expensive, but CubeSats offer a cost-effective path: their small mass and standardized design keep launch costs low, even if each unit carries only a handful of instruments. CuSP was thus also a proof-of-concept for assembling a distributed network of space science stations. The spacecraft carried three instruments: the Suprathermal Ion Spectrograph (SIS) from SwRI for detecting low-energy solar energetic particles, the Miniaturized Electron and Proton Telescope (MERiT) from NASA Goddard for counting high-energy particles, and the Vector Helium Magnetometer (VHM) from JPL for measuring magnetic field strength and direction.

Launch & Deployment

CuSP rode to space as a secondary payload aboard the Space Launch System's maiden flight, the Artemis 1 mission, which lifted off at 1:47 am EST on November 16, 2022. After the Orion spacecraft and its Interim Cryogenic Propulsion Stage performed a Trans-Lunar Injection and separated, CuSP was ejected from its launch canister within the ICPS. Just twenty-three minutes after deployment, the Deep Space Network picked up Open Loop Receiver telemetry confirming the spacecraft had booted up, detumbled, deployed its solar arrays, and locked into a Sun-pointing orientation. For the next hour and fifteen minutes, the satellite operated flawlessly, transmitting a steady carrier signal. Then the signal simply vanished. No further telemetry was ever received. Multiple recontact attempts through the end of 2022 all failed, and although the team planned to try again during an expected focal convergence, no further contact attempts were ultimately made. The mission was officially closed in December 2023.

Post-Mission Investigation

After the carrier signal disappeared, the CuSP team conducted thorough investigations into potential causes. One hypothesis involved a sudden battery temperature spike; however, by cross-referencing redundant sensor readings, engineers determined the excursion was actually a telemetry artifact. A single temperature monitor had saturated the analog-to-digital converter inputs for several signals, while the redundant monitors fed into an independent ADC showed no anomaly. A second anomaly—an unexpectedly high IRIS radio temperature reading—was traced by JPL engineers to a scaling equation in the SMOC EGSE that had never been updated. Once the corrected equation was applied, the reading normalized alongside all other temperatures. Despite these findings, no definitive root cause for the total loss of transmission was ever identified. The team exhausted recontact efforts, and with no further signals received, the mission was formally declared ended in December 2023.

Team & Spacecraft Architecture

The CuSP mission was led by Principal Investigator Dr. Mihir Desai at the Southwest Research Institute in San Antonio, Texas, with a team that included Project Manager Mike Epperly, Mission System Engineer Dr. Don George, Flight Software Engineer Chad Loeffler, and Spacecraft Technician Raymond Doty. Instrument leads included Dr. Frederic Allegrini (SIS), Dr. Neil Murphy (VHM), and Dr. Shrikanth Kanekal (MERiT). The spacecraft bus drew on a mix of SwRI and partner hardware: the SATYR Command and Data Handling Unit, SwRI flight software, a Clyde-Space electrical power system with BCR MPPT converters and LiPo batteries, deployable and fixed solar arrays, a VACCO MiPS cold gas thruster for propulsion and attitude control, and a Blue Canyon Technologies XACT ADCS with integrated thruster control. Deep-space communication relied on a JPL/SDL IRIS X-Band transponder, with mission operations handled by NASA GSFC and ground communication through the Deep Space Network.