Los Alamos research could help protect spacecraft from electrical failures

Space is a harsh environment, but new research from Los Alamos National Laboratory scientists could help engineers better protect spacecraft from electrical damage.

“These satellites are just bathed in a plasma environment all the time, and so it’s kind of like a bird sitting on a high voltage wire,” said Los Alamos scientist Brian Larsen, who worked on the research.

“And the bird could sit on the high voltage wire just fine, but when it touches two wires, bad things happen. We haven’t had the ability to measure the (electrostatic) discharges — that’s the possible bad thing happening — since 1979, (that) was the last time we had these instruments on the same vehicle.”

Researchers who worked on the study specialize in plasma and lightning, from just above the Earth’s surface, in high atmosphere, all the way into space. They set out to better understand lightning and the plasma environment around spacecraft by using two different sensors placed on a Department of Defense satellite in geostationary orbit, called STP-Sat6. One sensor looked at radio frequency signals, while the other measured the number and activity of electrons. Electrons are subatomic particles that are part of every atom.

Space is full of charged particles, and scientists have long known that sensitive electronic equipment and communication systems on satellites can be damaged by fast electrical breakdowns, called spacecraft environment discharges.

Most spacecraft aren’t equipped with a sensor to detect spacecraft environment discharges, said Erin Lay, another scientist who worked on the research.

Researchers noticed a potential correlation between the number of electrical discharges and the number of electrons in the surrounding environment, a correlation they began tracking.

“So we were trying to study lightning, which produces these giant electrical sparks, if you will, in the Earth’s atmosphere, and produces the same sort of signals that then propagate to space,” said Los Alamos scientist and the study’s lead author Amitabh Nag. “Our space based sensor was looking for those. But it turns out that same sensor can also sense these discharges that are much smaller, most likely occurring in the spacecraft’s own environment.”

They examined more than a year of data from the two sensors and found a direct correlation between the number of electrical discharges and the number of electrons in the surrounding environment. The peaks in spacecraft environment discharges correlated with the peaks in electron accumulation. In about three-fourths of cases, peaks in electron activity came 24 to 45 minutes before the spacecraft environment discharge events.

The 20- to 40-minute delay suggests the buildup of charge from low-energy electrons plays a key role in priming the spacecraft for electrostatic discharges.

They published their findings in the journal Advances in Space Research earlier this month.

It makes sense that if there are a lot of charged particles, they will accumulate and eventually discharge, said Nag.

“But just because we expect it doesn’t mean that the data will show it so clearly. And so it was very fulfilling to actually see measurements that 36,000 kilometers from the Earth’s surface with the data we were seeing, these things line up as we had expected them to,” Nag said.

Better understanding the connection between the charged particles around spacecraft and electrical discharges could improve estimates for how long equipment will last in space and help quantify how regularly scientists have to worry about electrostatic discharges on their satellites, according to Nag.