TRW delivers radiation-hardened satellite chips

TRW Inc. last week announced the final delivery to the Air Force of a high-performance, radiation-hardened microprocessor capable of supporting military and commercial satellite and guided-missile requirements.

Completing a 1990 contract awarded by the Air Force Research Laboratory Information Directorate, Rome, N.Y., TRW delivered five single-board computers along with commercial software tools for use in commercial communications systems, military satellite communications, wideband communications systems, next-generation surveillance and missile warning systems, and strategic missile systems.

The new RH32 32-bit radiation-tolerant microprocessor is based on MIPS Technologies Inc.'s R3000 reduced instruction-set computing architecture. It provides more than a sevenfold improvement in performance over older hardened microprocessors and is supported by a wide range of commercial off-the-shelf software tools, according to TRW officials.

"The state of the art right now is 16-bit," said Maria Tirabassi, the RH32 program manager for TRW. However, the RH32 "gives you a factor of 20X improvement over what exists today in terms of radiation tolerance and performance."

The new processor architecture also is uniquely scalable, enabling satellite operators to link up to four processors and run them in parallel, said Dave Williamson, an electrical engineer with the Air Force Research Lab's Multi-Technology Integration Branch.

The vulnerability of COTS microprocessors and electronic components to high levels of X-ray radiation surfaced in 1994. That year, Lt. Col. Glenn Kweder of the Defense Nuclear Agency— now known as the Defense Special Weapons Agency— gave a briefing to the director of the National Reconnaissance Office in which he said, "A single low-yield nuclear weapon detonated at high altitude can negate a majority of [low-Earth-orbit] space assets in a few months" [FCW, June 22].

Electrons become trapped in so-called Van Allen Belts when a nuclear device is detonated in the atmosphere. Van Allen Belts are radiation belts that circle the globe and are held in place by the Earth's magnetic field. A nuclear detonation increases the number of electrons in the Van Allen Belts, causing the electronic components of satellites to "fry" in a matter of hours. The radiation also can significantly shorten the life span of satellites.

According to Tirabassi, the RH32 is radiation-hardened to one Mrad, ensuring reliable performance in high natural radiation environments where commercial low-Earth-orbit and medium-Earth-orbit satellites typically operate. In addition, the processor is protected against single-event failures, prompt dose rates of radiation from nuclear detonations, lock-up and total dose rates that occur over long periods, Tirabassi said.

"The new design provides an extra cushion for harsher radiation environments," Williamson said.

It also was designed to withstand increased radiation caused by the detonation of nuclear weapons in the atmosphere, he said. "If it does take a hit, it [also] can correct itself, which really hasn't been a capability that the commercial market has been too concerned about."