A datasheet that lists "10kRad TID" tells you a device was tested against radiation. It doesn't tell you what happened during that test, or if the unit kept performing once the dose was applied. For a procurement or program manager reviewing IMU options for a space mission, that distinction is where risk assessment should begin.

Two Different Threats, Two Different Tests

Radiation testing for space hardware covers two distinct failure mechanisms. Total Ionizing Dose (TID) to measure the cumulative degradation over a mission's lifetime and Single Event Effects (SEE) to measure how a device responds to occasional high-energy particle strikes, which can instantly disrupt operation rather than building over a long period of time.

What Our DMU41 Testing Showed

8 Units of our DMU41 were put through SEE testing at 50, 100, 150 and 200 MeV. At 50 MeV, testing recorded a drop in current consumption with normal operation continuing throughout, no power cycle required, alongside one instance where communication stopped and a power cycle was needed to restore it. At 100, 150 and 200 MeV, a similar pattern held: some events required power cycling to recover, but in every case normal operation resumed afterward.

Following testing, the Acceptance Test Procedure (ATP) confirmed no significant drift in performance, and all units remained within performance limits throughout. For TID, the units were tested to 30kRad(Si), three times the 10kRad benchmark typically associated with Low Earth Orbit (LEO) missions. The results indicated the DMU41 was suited for LEO missions with 10kRad exposure, or for Geostationary Earth Orbit (GEO) missions with additional shielding applied.

Why "Recoverable" Matters More Than "Zero-Event"

No sensor operating in orbit is immune to particle strikes, the relevant question for a program manager isn't whether an event occurred, but whether the device remained fully functional afterward. An occasional power cycle in response to a high-energy strike is a known and manageable operational response, not a failure mode that puts a mission at risk.

The DMU41's reset architecture explains why this response is manageable rather than concerning. A watchdog continuously monitors the main processor and triggers an internal reset if it detects a lockup, the most common effect of a high-energy strike. Critical silicon not controlled by the processor, including the communication chip, main regulators, and power to the processor itself, is hardwired active by design. This means the unit is always able to re-establish operation, even in the rare case where a full power cycle is what's needed to clear an event.

What matters is that, across every dose level tested, the DMU41 returned to normal operation and showed no lasting performance degradation.

The Takeaway

A radiation figure on a datasheet is a starting point, not proof of reliability. What de-risks a program is visibility into test conditions, observed effects, and confirmed post-test performance - the detail that shows a device doesn't just survive a dose, but keeps working afterward.

That's what our DMU41 radiation testing report sets out - the complete SEE and TID results behind the figures discussed here. It's available on request, so if you'd like a copy, or want to talk through what it means for your program, you can contact one of our sales team at [email protected]