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 the photo voltaic system’s most intense planetary radiation fields. When the spacecraft’s JunoCam—a colour, visible-light digital camera—started to undergo the results in December 2023, the mission group again on Earth had to consider a distant repair earlier than they misplaced their likelihood 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 offered insightful classes on spacecraft radiation tolerance for mission scientists past the Juno group, in keeping with a Jet Propulsion Laboratory statement printed yesterday.

Scientists estimated that JunoCam, whose optical unit is situated outdoors of a protecting radiation vault, might 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 look at radiation harm.

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

“We knew annealing can generally alter a fabric like silicon at a microscopic degree however didn’t know if this may repair the harm,” Jacob Schaffner, a JunoCam imaging engineer from Malin Area Science Techniques, 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 strategy efficiently enabled JunoCam to seize clear images for a number of orbits, the spacecraft continued to barrel into Jupiter’s radiation fields, and the harm was quickly obvious once more.

“After orbit 55, our photos have been filled with streaks and noise,” defined JunoCam instrument lead Michael Ravine, additionally from Malin Area Science Techniques. “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 best way 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 strategy received nearer, and with simply days to go, the pictures out of the blue improved considerably. On December 30, 2023, JunoCam efficiently captured detailed photographs of Io’s north polar area, together with beforehand undocumented volcanoes. Scientists introduced 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 latest 74th orbit, “Juno is educating us the way to create and preserve spacecraft tolerant to radiation, offering insights that may profit satellites in orbit round Earth,” defined Scott Bolton, Juno’s principal investigator from the Southwest Analysis Institute. “I count on the teachings discovered from Juno shall be relevant to each protection and industrial satellites in addition to different NASA missions.”