Toyota Recall Might Be Caused by Cosmic Rays

It may not lessen Toyota's woes to hear that the problems the company has been having with faulty gas pedals could be blamed on cosmic rays from space. Sound unbelievable? The concept is actually a lot more plausible than you might think. 

Toyota's sticky gas pedals caused sudden and unintended acceleration in several of the automaker's top-selling Toyota and Lexus-brand cars, which led to a massive recall of more than 9 million vehicles worldwide, beginning in November. While ongoing inquiries attempt to locate the source of the problem and figure out a fix, investigators might find it useful to examine a far-out culprit: cosmic ray radiation from deep in the cosmos, which has been known to plague vulnerable data and memory chips in electronics.

Cosmic rays could be at least partially to blame for Toyota's mechanical defects, scientists now say. And the problem could get worse in the future, as the increasing use of tiny computer chips — replacing mechanical parts — makes cars more and more vulnerable to space radiation.

More sensitive electronics

Federal regulators were prompted to look into the possible role that cosmic rays played in Toyota's product recall fiasco after an anonymous tipster suggested the design of Toyota's microprocessors, software and memory chips could make them more vulnerable to interference from radiation compared with other automakers. This is because Toyota has led the auto industry in its widespread inclusion of electronic controls in the manufacture of their various car models.

As electronic devices are made to perform more and more functions on smaller circuit chips, the systems become more sensitive and vulnerable to corruption, and thus more prone to interference from radiation, said Ewart Blackmore, a senior researcher at TRIUMF, a cyclotron facility in Vancouver, Canada, that works with companies to test and analyze the effects of radiation on products.

"Radiation is certainly a potential cause of Toyota's problems," Blackmore told LiveScience. "What's not known is what direction Toyota and other automakers are taking in terms of finding and correcting these issues."

What are cosmic rays?

As a start, automakers and regulators need to understand the complex and sometimes mysterious ways cosmic rays affect electronics on Earth.

Cosmic rays are high-energy protons that originate in shock waves from the remnants of supernovas – the death heaves of giant exploded stars. Cosmic rays constantly rain down on Earth. And while the high-energy "primary" rays collide with atoms in the Earth's upper atmosphere and rarely make it through to the ground, "secondary" particles are ejected from these collisions and do reach ground level.

The effect is similar to a cue ball striking a rack of balls in the game of pool, said Robert Rauk, a consultant at Creative Power Resources, Inc., a Philadelphia-based electrical and mechanical engineering consulting company.

"These secondary particles bathe the Earth in energetic showers that can disrupt electronics," Rauk said in an e-mail interview. "The effect depends on how sensitive the spot is that was struck."

High-energy particles and electronics

Electronic chips record, store and process information in the form of "bits." High-energy particles that pass through these chips can alter or "flip" a bit, resulting in a Single Event Upset (SEU).

This event can be anything from data loss or altered programming, to much more serious corruptions of circuitry functions.

The risks are especially high for circuits that are "field programmable," explained Lloyd W. Massengill, director of engineering at the Vanderbilt Institute for Space and Defense Electronics at Vanderbilt University. Field-programmable circuits are systems in which the circuit's function can be electrically altered while it is still in use.

"These circuit families store not just data, but their basic function electrically," Massengill said. "In the unfortunate event of a particle flipping just the right bit, a circuit configured to carry out a benign action may be reprogrammed to carry out some unintended action."

Testing cosmic-ray effects

Massengill and his colleagues have been studying Single Event Upsets in commercial, space and military systems since 1987. SEUs were first observed in the late 1970s, and since then, extensive research and testing has been done in the military, space and avionics industries. But the effects of radiation have received very little attention among automakers and their regulatory bodies, Massengill said.

Given the rapid pace of technological innovation, and the nature of our increasingly pervasive digital world, researchers like Blackmore and Massengill believe it is becoming even more important for manufacturers to test their products and develop software and microelectronics that are impervious to such cosmic corruption.

"Mechanical controls are disappearing," Massengill said. "Most everything we do is becoming reliant on digital information processing. We are approaching the case where a single bit of critical information may be stored with just a thousand electrons; a single particle can easily overcome such small charge quantities, leading to a bit corruption.

He added that "control by wire" systems in which electronic circuits replace cables and gears, are becoming commonplace in automobiles, aircrafts and defense systems.

To conduct radiation tests, facilities like TRIUMF shoot proton and neutron beams at the circuits and microelectronic components in order to observe any errors. The beams can simulate years of operation in a matter of minutes and are used to interrogate the systems to ensure they function properly in spite of exposure to radiation.

Still, it is difficult to know exactly how much radiation testing is already being done within the auto industry. According to Blackmore, none of the companies that utilize the TRIUMF facility are building components specifically for automobiles, although TRIUMF does conduct testing on software and memory chips that are manufactured and sold to a variety of clients, which could include automakers.

In the wake of Toyota's recall, Blackmore recommends that radiation testing be far more widespread in the auto industry, in order to continue to protect vehicle software against the potential negative effects of radiation.

"There is enough processing power in the memory devices in automobiles to attract errors," Blackmore said. "What is still unclear is whether the industry has put in place the right mitigation techniques to prevent errors in their systems."

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