Argus: Space Radiation on Modern Electronics
Argus is a collaborative project between SSRL and the Institute for Defense and Space Electronics (ISDE) at Vanderbilt University. Argus’ mission is to improve the ability to model the effects of space radiation on modern electronics. We will do this by comparing the rates of on-orbit radiation events against the predictive models developed by ISDE. Argus is a 2U CubeSat (10x10x20 cm) with a mass of 3.0 kg designed to operate in Low Earth Orbit.
Argus is SLU’s entry into the University Nanosat-7 Competition, which began in January 2011 and culminated in a Flight Competition Review in January 2013. In February 2012, Argus was selected by NASA for a sponsored launch under its Educational Launch of Nanosatellites (ELaNa) Program. Argus was launched on 3 November 2015 as part of the ORS-4 Mission on the inaugural flight of the Super-Strypi rocket out of Hawaii. Unfortunately, the launch failed early in the flight, and Argus did not reach orbit.
The motivation for Argus is straightforward: the models used today to determine how electronic devices will operate when exposed to space radiation were created in the 1970s and ‘80s, and are tailored to the kinds of electronics available in the 1970s and ‘80s using the computational resources in the 1970s and ‘80s. Modern electronics are smaller, faster and more complex than their predecessors. The existing models to define their reliability in space simply do not apply.
Researchers at Vanderbilt University and ISDE have developed new predictive models, but it is important to calibrate them. Unfortunately, it is not sufficient to simply calibrate the models only using radiation test chambers on the ground. Modern electronics have many operating modes and are susceptible to a wide range of particles and energies; testing even one simple device across all parameters would require years of beam time! Beam time is a necessary element of calibration, but it is not sufficient.
With the advent of the CubeSat standard and the universal adoption of the P-POD carrier among U.S. and international launch vehicles, spaceflight has become a cost-effective complement to ground testing.
We did this by comparing the rates of on-orbit radiation events against the predictive models developed by ISDE. Argus was a 2U CubeSat (10x10x20 cm) with a mass of 3.0 kg designed to operate in Low Earth Orbit.
Argus consisted of a SLU-built bus and the Independence payload developed by Vanderbilt University. After separation from the launch vehicle, Argus passively detumbled, unstowed the downlink antenna, and remained in safe mode until contacted by the ground. Once checked out, Argus entered into nominal operations:
· The Independence payload actively monitored its own experiments via the Vanderbilt University Controller (VUC).
· When a radiation-induced event occurs, the VUC logged the event.
· The bus broadcasted regular beacons of vehicle state of health and selected science snapshots.
· Ground operators at SLU and VU contacted Argus to download the complete science & engineering history.
· Researchers at ISDE compared the predicted event rates against the flight data to improve the models.