The ‘Hail Mary’ That Saved NASA’s Juno Digicam From Jupiter’s Radiation Hell

NASA’s Juno spacecraft, which launched in 2011 to research Jupiter’s origin and evolution, travels by way of the photo voltaic system’s most intense planetary radiation fields. When the spacecraft’s JunoCam—a coloration, visible-light digital camera—started to endure the implications in December 2023, the mission workforce again on Earth had to think about a distant repair earlier than they misplaced their probability to {photograph} the Jovian moon, Io.

A comparatively easy course of was in the end what enabled the long-distance save: heating the instrument earlier than slowly cooling it down (I belief they tried turning it on and off once more). The expertise has supplied insightful classes on spacecraft radiation tolerance for mission scientists past the Juno workforce, in line with a Jet Propulsion Laboratory statement printed yesterday.

Scientists estimated that JunoCam, whose optical unit is situated outdoors of a protecting radiation vault, may resist radiation for the spacecraft’s first eight orbits round Jupiter. It wasn’t till Juno’s forty seventh orbit, nonetheless, that the scientists started to watch radiation injury.

The workforce recognized proof suggesting that the radiation had broken the voltage regulator, which is essential to JunoCam’s energy provide. From a whole bunch of hundreds of thousands of miles away, their choices had been restricted. As such, they determined to strive a lesser-known course of referred to as annealing, which consists of heating a fabric for a given period of time to scale back its defects earlier than slowly cooling it down.

“We knew annealing can typically alter a fabric like silicon at a microscopic degree however didn’t know if this might repair the injury,” Jacob Schaffner, a JunoCam imaging engineer from Malin Area Science Methods, mentioned within the assertion. “We commanded JunoCam’s one heater to boost the digital camera’s temperature to 77 levels Fahrenheit [25 degrees Celsius]—a lot hotter than typical for JunoCam—and waited with bated breath to see the outcomes.”

Whereas their method efficiently enabled JunoCam to seize clear pictures for a number of orbits, the spacecraft continued to barrel into Jupiter’s radiation fields, and the injury was quickly obvious once more.

“After orbit 55, our photos had been filled with streaks and noise,” defined JunoCam instrument lead Michael Ravine, additionally from Malin Area Science Methods. “We tried completely different schemes for processing the pictures to enhance the standard, however nothing labored. With the shut encounter of Io bearing down on us in a couple of weeks, it was Hail Mary time: The one factor left we hadn’t tried was to crank JunoCam’s heater all the way in which up and see if extra excessive annealing would save us.”

At first, the extra excessive annealing didn’t appear to supply any enhancements, however because the Io method obtained nearer, and with simply days to go, the pictures all of the sudden improved considerably. On December 30, 2023, JunoCam efficiently captured detailed photographs of Io’s north polar area, together with beforehand undocumented volcanoes. Scientists offered the accomplishment on the Institute of Electrical and Electronics Engineers Nuclear & Area Radiation Results Convention in Nashville on July 16.

Although the picture corruption returned throughout its current 74th orbit, “Juno is instructing us find out how to create and keep spacecraft tolerant to radiation, offering insights that can profit satellites in orbit round Earth,” defined Scott Bolton, Juno’s principal investigator from the Southwest Analysis Institute. “I anticipate the teachings discovered from Juno might be relevant to each protection and business satellites in addition to different NASA missions.”