White Paper

Protecting Satellite Image Integrity from Radiation

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WHITE PAPER Rad-tolerant storage mrcy.com 4 Because every mission has a unique set of requirements, the storage subsystems are tunable to balance power consumption, ECC functions and storage capacity. Radiation shielding is also a mission-specific option, customized in conjunction with the mission's imaging system designers. The NAND flash implementation is worth some discussion. Flash memory designed specifically for rad tolerance has significantly reduced per-chip storage capacity compared with standard chip versions. For that reason, Mercury chose to use industrial SLC NAND flash devices determined to be tolerant to at least 30 krad, then added superior storage reliability via mathematically rigorous horizontal Reed-Solomon ECC. The NAND flash parts are screened in accordance with NASA's EEE-INST-002 instructions, while each lot of NAND parts undergoes radiation lot acceptance testing (RLAT) and destructive physical analysis (DPA) before screening. THE ADVANTAGES ARE CLEAR Mercury's rad-tolerant storage product family is unique in meeting the requirements of today's most advanced satellite imaging programs, with a design approach that will use tomorrow's technologies right now to maintain that leadership. The performance and operational advantages include: Highest-density rad-tolerant storage – All form factors contain a large amount of storage capacity in a small form factor. For example, the 3U VPX RH3440 has 440 GB of data storage capacity in a 406 cm 3 package. Compact and lightweight – Designed in a 3U form factor, our SSDRs meet the needs of next-gen LEO satellites. Extreme reliability – Mercury 's storage technology design has no microprocessor or software, always potential failure points. It uses a triple redundant RTG4 rad-tolerant FPGA to control the NAND flash. Powerful ECC, capable of correcting data from multiple NAND devices, and hot-swap replacement of failing NAND devices add further layers of reliability. Long-term mission support – Designed to meet the five- year operational lifetimes of advanced imaging programs. Constant capacity over the entire product life – Automatic replacement of worn-out NAND blocks means the imaging system always has the same view of storage capacity. Standards-based solutions – Our SSDRs are packaged in 3U VPX and 6U VPX form factors, not proprietary enclosures. Continuing commitment – Mercury has not created a one-off product but rather a product family with an evolving roadmap to deliver the most innovative space technology solutions. Other Applications Also Need Radiation Tolerance Satellite imaging is not the only application set requiring rad-tolerant data storage. High-altitude airplane imaging is a similar, but distinct, area. Flights at 40,000 feet or more are often used to collect extremely detailed images of ground artifacts — images which are stored on the aircraft until it returns to its base. At 40,000 feet, cosmic radiation is not at space levels but it is still intense and a serious issue that must be addressed. Mercury's rad-tolerant storage subsystems meet the need, as off-the-shelf, standards-based solutions that are lightweight and low-power. Even on the Earth's surface, medical imaging and nuclear power generation create environments with high levels of radiation. Rad-tolerant storage from Mercury is a reliable way to ensure data integrity for any data collected and stored within those environments. RH3440 Radiation-Tolerant SSDR

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