What is MRAM and Why is it Critical to Mission Success?
What is MRAM and Why is it Critical to Mission Success?
Cosmic radiation wreaks havoc on electronic components critical to the mission success of satellites and other spacecraft. That’s why engineers designing new-generation satellites or setting their sights on exploring the moon, Mars and other heavenly bodies usually specify radiation-hardened integrated circuits for their projects.
So, what is MRAM and why is it critical to future manned and unmanned space missions?
Radiation-hardened circuits – like the Magneto Resistive Random-Access Memory (MRAM) ICs Honeywell produces – are built to withstand the barrage of ionizing radiation and radiation effects commonly found in space. The exact conditions a spacecraft will encounter depends on its mission, but whether it’s taking a trip around the sun or heading to the far reaches of the solar system, every component onboard has to be rugged enough to withstand the extreme conditions of space.
For example, Earth is surrounded by two radiation belts that spacecraft must pass through or operate within. Now consider Jupiter, the destination for several upcoming space mission, which has radiation belts 10,000 times stronger than Earth’s. Solar winds and galactic cosmic rays – particle fragments from exploded stars – are found everywhere in space. Spacecraft and all the equipment they carry need to be designed to survive and function normally under these extremely punishing conditions.
Unlike conventional circuits, MRAM circuits use magnetic spintronic elements in place of collections of electron charges to store data. Exposure to the charged ions in outer space can disrupt the electron charges on conventional chips, causing them to fail or malfunction. That’s not an issue with MRAMs, in which magnetic coupling in magnetic spintronic elements mitigates sensitivity to charged ions and ionizing radiation.
MRAMs also offer nonvolatility in addition to fast processing, greater density and low power consumption when compared to other memory technologies such as static RAM or dynamic RAM circuits which are volatile memories.
MRAMs are nonvolatile, to allow data to be retained even when power is removed to support system recovery and “instant on” computing, and offer practically unlimited durability in terms of cycling and retaining data. They can significantly improve microelectronic products and system performance by storing greater amounts of data and enabling it to be accessed faster with greater reliability. MRAM is considered a universal memory that can be applied to any use, from system computing to storage.
Honeywell packs a lot of performance into its MRAM circuits, according to Lisa Napolitano, Sr. Director of Microelectronics for Honeywell Aerospace. “The circuits we provide for NASA, other U.S. and foreign space agencies, and the commercial space industry need to perform flawlessly for 15-20 years or even more,” she said. “Replacing them if they fail is obviously not an option so they simply can’t fail.”
In fact, unlike the most popular nonvolatile memory type, flash memory, MRAM never wears out and can theoretically be written to and read from until the physical material itself degrades. This makes the Honeywell MRAM the perfect choice for space exploration missions and satellites that will remain in orbit for an extended period of time.
“It sounds like bragging to say these circuits are indestructible,” Napolitano said. “But they are extremely robust and built to withstand the harshest environments known to exist, including extreme heat, extreme cold and exposure to high doses of radiation. We’re not aware of any case where an MRAM has failed due to exposure to the extreme elements of space.”
MRAM circuits can be used to process data onboard the spacecraft, which can be much more efficient than gathering information, transmitting it to ground-based operations for processing and then sending it back to the spacecraft.
“The circuits we manufacture today have higher capacities and bandwidth, faster speeds, and smaller size and mass than was available in preceding technology, even tracing back to magnetic core and magnetic plated wire memories that were used in the prior century,” said Engineering Fellow Romney Katti. “The chips we are envisioning and designing now will offer even greater performance for upcoming applications.”
“We’ve certainly come a long way from the time of the Space Shuttle, which used memory sizes quantified in kilobits,” he added. “Today Honeywell is working on the first 64-megabit radiation-hardened monolithic nonvolatile MRAM microcircuit for space applications, with a view towards 1 gigabit radiation-hardened monolithic nonvolatile MRAM microcircuits and beyond.”
Honeywell has more than 25 years of experience in developing and producing microelectronics for all kinds of aerospace and defense applications. Katti was part of a team of Honeywell engineers that worked with the Defense Advanced Research Projects Agency (DARPA) and an industry team that included Honeywell, IBM and Motorola to pioneer the MRAM technology beginning in the 1990s.
MRAM technology has continued to advance, leading now to the application of magnetic spintronic devices using spin-transfer torque to write and tunneling magneto-resistance to read an MRAM cell.
Today, Honeywell offers 1 Mb and 16 Mb radiation-hardened monolithic MRAM products, along with a 64 Mb radiation-hardened MRAM multi-chip module, to meet the needs of many space applications, with the 64 Mb radiation-hardened monolithic chip on the near-term horizon. Honeywell MRAM circuits give designers a commercial-based memory technology with high performance and high reliability that also withstands the harsh environments of space, including radiation exposure and extreme temperatures.
Those are exactly the kind of conditions spacecraft will encounter as NASA, the European Space Agency (ESA) and other public and private space entities tackle an ambitious slate of space exploration missions in the next decade. Included are new missions to the moon, Mars, Jupiter, and Europa and Titan, two of Jupiter’s moons.
“With the proliferation of new commercial satellite constellations and some very exciting exploratory missions on the horizon, we continue to build on Honeywell’s rich microelectronics legacy with new and better solutions, better quality and expanded capacity to address our customers’ most pressing needs,” Napolitano said.
“MRAM circuits outperform alternative technologies, retain data for decades and provide unlimited endurance,” she added. “We’re proud of the products we produce today at our Minnesota foundry and we’re excited about the future and our commitment to deliver outstanding mission reliability to our customers.”
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