MRAM, based on the magnetic state of ferromagnetic materials, eliminates dependence on stored charge, making it inherently more robust against radiation-induced effects.
MRAM Operating Principles
MRAM stores information using a magnetic tunnel junction (MTJ), composed of:
A fixed magnetic layer,
a free magnetic layer,
and an ultrathin insulating barrier between them.
The logic bit is determined by the relative orientation of the magnetization:
Parallel → low resistance (e.g., “0”)
, Antiparallel → high resistance (e.g., “1”)
Writing Technologies
Modern space-grade implementations primarily use:
STT-MRAM (Spin-Transfer Torque)
Spin-biased current writing
SOT-MRAM (Spin-Orbit Torque) (still under evaluation for space)
Improves durability and separates read/write paths
Space Grade Requirements
To be considered space grade, an MRAM must meet strict standards:
Tolerance to radiation
TID (Total Ionizing Dose): > 100 krad(Si), in some cases > 300 krad
SEE (Single Event Effects):
SEU (Single Event Upset)
SEL (Single Event Latch-up)
SEFI (Single Event Functional Interrupt)
MRAM presents natural immunity to SEU in the memory cell, with peripheral circuits being more vulnerable.
Environmental conditions
Typical temperature range: –55 °C to +125 °C
High resistance to vibration and mechanical shock (launching)
Reliability
Data retention > 10 years (frequently > 20)
Endurance > 10¹² write cycles
Advantages of MRAM in Space Applications
No real volatility.
Data is retained without power, enabling:
Instant-on startup;
Elimination of backup memory
High robustness against radiation.
By not storing electrical charge:
Lower susceptibility to TID.
Drastic reduction in SEU compared to SRAM and DRAM.
Low power consumption
. More efficient writing than Flash.
Ideal for satellites with limited power budgets.
Architecture simplification:
A space-grade MRAM can replace:
SRAM + Flash + EEPROM,
reducing system mass, volume, and complexity.
Use Cases in Space Systems
On-Board Computers (OBCs)
Attitude and Orbit Control Systems (AOCS)
Scientific Payloads
FPGAs and SoCs with embedded non-volatile memory
Fault-tolerant and safe mode systems
Comparison with Other Technologies
Non-volatile Technology Radiation Tolerance Endurance Speed
SRAM rad-hard No Medium High Very high
Flash Yes Low–Medium Limited Low
EEPROM Yes Medium Low Very low
MRAM Yes High Very high High
Challenges and Limitations
Despite its advantages, space-grade MRAM faces several challenges:
High cost compared to commercial memories
Lower density than advanced Flash
Technological maturity: less track record in long-duration missions
Need for additional hardening in CMOS peripherals
Future Trends
Current development lines include:
Embedded MRAM in space SoCs
Integration with space-grade RISC-V processors
SOT-MRAM for greater endurance
Certification for deep space and New Space missions
Conclusion:
Space-grade MRAM represents a paradigm shift in memory design for space systems. Its combination of non-volatility, high radiation tolerance, speed, and reliability makes it one of the most promising technologies for future space missions, both institutional and commercial. Although challenges remain regarding cost and density, the evolution of MRAM points to increasingly widespread adoption in critical space architectures.
