All 2015 Content
Session
Technical Session X: Advanced Technologies II
Abstract
Xiphos has been supplying SD equipped processors to spacecraft developers in low-earth orbit applications since 2006. Despite early successes, some failures have occurred resulting in fallback to redundant hardware. Although rarely documented in the literature, other small/COTS spacecraft developers have encountered failures with SD cards on-orbit. This has led to an understandable concern on the part of end-customers and spacecraft integrators in the use of these devices. Xiphos has executed many different test campaigns during the past decade to determine the best manner to replicate on-orbit error behavior and to establish mitigation techniques. Each failure event is unique, but a common symptom is an increase in continuous/standby current consumption. The level is on the order of twice the maximum expected current, but substantially less than a latch-up event. Test campaigns at TRIUMF's Proton Irradiation Facility have shown resilience to data loss in biased conditions with total dose of greater than 20 krad. Recent testing with energies between 13 and 105 MeV have shown similar "low-current latch-up" behavior but without the apparently permanent damage witnessed on-orbit. Xiphos is confident that rapid event detection techniques, along with several other robust design elements can permit long-term and reliable use of microSD on-orbit.
Presentation
MicroSD Operational Experience and Fault-Mitigation Techniques
Xiphos has been supplying SD equipped processors to spacecraft developers in low-earth orbit applications since 2006. Despite early successes, some failures have occurred resulting in fallback to redundant hardware. Although rarely documented in the literature, other small/COTS spacecraft developers have encountered failures with SD cards on-orbit. This has led to an understandable concern on the part of end-customers and spacecraft integrators in the use of these devices. Xiphos has executed many different test campaigns during the past decade to determine the best manner to replicate on-orbit error behavior and to establish mitigation techniques. Each failure event is unique, but a common symptom is an increase in continuous/standby current consumption. The level is on the order of twice the maximum expected current, but substantially less than a latch-up event. Test campaigns at TRIUMF's Proton Irradiation Facility have shown resilience to data loss in biased conditions with total dose of greater than 20 krad. Recent testing with energies between 13 and 105 MeV have shown similar "low-current latch-up" behavior but without the apparently permanent damage witnessed on-orbit. Xiphos is confident that rapid event detection techniques, along with several other robust design elements can permit long-term and reliable use of microSD on-orbit.
