EE Times paper proposes right-sized radiation specs for NOR flash

Paper proposes a new way to spec space-grade memory

EE Times has published a technical paper arguing that radiation requirements for NOR flash memory on space missions should be tailored to each mission rather than set by a blanket worst-case specification. NOR flash is a type of non-volatile memory that keeps data when power is off and is widely used to store code on spacecraft electronics.

The paper describes a method for deriving those requirements from four mission inputs: the orbit, the planned lifetime, the level of shielding, and the risk tolerance of the mission. According to EE Times, this approach is meant to produce memory specifications that fit the mission instead of over-engineering them.

How radiation damages NOR flash

The paper examines two radiation mechanisms that degrade NOR flash in orbit. The first is total ionizing dose, the cumulative charge build-up that components absorb over time in a radiation environment. The second is single-event effects, sudden disturbances caused by individual energetic particles striking the chip.

A key point of the analysis is that the storage array itself is often not the first part to fail. The paper focuses on the charge pumps, sense amplifiers and control logic, circuits that EE Times says frequently fail before the memory cells do. That distinction matters because it changes where engineers should focus their testing and design effort.

A lean qualification flow

Alongside the requirements method, the paper outlines a lean qualification flow for space-grade memory. It is built on three elements: process traceability, proportionate reliability testing, and standardised characterisation of total ionizing dose and single-event effects tied to lot acceptance.

Lot acceptance means testing samples from each manufacturing batch rather than relying only on data from earlier production runs. The goal, according to the paper, is evidence that is auditable without imposing the cost and lead time of a full traditional space qualification programme.

Seven steps for component selection

The paper closes with a seven-step framework that engineers can apply during component selection. The framework is intended to lead to memory specifications that match the needs of a specific mission and are backed by auditable evidence rather than generic data sheets.

For the growing commercial space sector, the approach reflects a wider tension: traditional space-grade components offer proven reliability at high cost and long lead times, while commercial parts are cheaper but need careful radiation analysis. This paper positions its method as a middle path, though its recommendations remain the author's proposals rather than an adopted industry standard.