For nearly a decade, a significant probe has endured the challenging environment of Jupiter to deliver captivating close-up images of the planet and its moons. Recently, however, the gas giant momentarily outwitted the mission. The Juno spacecraft unexpectedly entered a safe mode during a scheduled flyby of Jupiter, leading to a temporary shutdown of its scientific instruments.
During its 71st close approach to Jupiter, Juno entered precautionary status twice on April 4, as reported by NASA. The exact cause of this safe mode activation remains unclear, but it is believed to have occurred as Juno traversed Jupiter’s radiation belts.
Communication with Juno was reestablished, revealing that the spacecraft first activated safe mode at 5:17 a.m. ET, approximately an hour before the scheduled flyby. Juno entered safe mode again around 45 minutes after its closest approach to the planet, known as perijove. In safe mode, nonessential functions are halted while the spacecraft maintains its communication and power systems. Juno rebooted its computer and aligned its antennas with Earth to ensure communication.
Safe mode is initiated when the spacecraft detects an anomaly. Although the team is still analyzing the data to determine the root cause, initial indications suggest that Juno was flying through Jupiter’s radiation belts at the time of the activation.
Jupiter’s magnetic field, which is 20,000 times stronger than Earth’s, is the most powerful among the planets in the solar system. The magnetosphere of Jupiter captures and accelerates charged particles, similar to a particle accelerator, according to the European Space Agency. The most intense fluxes of energetic particles occur in the radiation belts around Jupiter’s equator.
To shield against high-energy particles, Juno is equipped with a titanium radiation vault, although this protection has proven inadequate on occasion. Since its arrival at Jupiter in 2016, Juno has entered safe mode four times.
Following the reestablishment of communications, the team is now focused on transmitting data collected before and after the activation of safe mode while conducting flight software diagnostics on the spacecraft, as noted by NASA.
Juno is set for another flyby of Jupiter on May 7, during which it plans to closely approach the Jovian moon Io at a distance of approximately 55,300 miles (89,000 kilometers). It is hoped that Juno will manage to operate its scientific instruments without interruption during this mission.