NASA's Juno Spacecraft Enters Safe Mode During Jupiter Flyby

The Juno spacecraft, operated by NASA, experienced an anomaly during its 71st close flyby of Jupiter, resulting in the activation of its safe mode. This precautionary measure may be linked to the intense radiation surrounding the planet.

On April 4, Juno initiated its approach to Jupiter, entering safe mode on two occasions: firstly at approximately 11:17 AM local time, just an hour before its closest approach, known as perijove, and again 45 minutes after passing the planet.

Safe mode is a protective status activated when the spacecraft detects irregularities. In this mode, non-essential functions are disabled to preserve critical operations such as power management and communication. During this period, Juno aligns its antenna toward Earth to maintain contact and subsequently reboots its systems.

All systems on board have since returned to normal functionality. Juno's scientific instruments were inactive throughout the flyby, but NASA reported that the processes for transitioning to safe mode were executed as designed. Following the incident, the spacecraft conducted a diagnostic check of its flight software, reestablished communication with mission control, and is now set to transmit the technical and scientific data collected before and after the safe mode events for analysis.

Jupiter is known for having the strongest radiation belts in our solar system. These belts consist of high-energy charged particles trapped by the planet's magnetic field, which is approximately 20 times stronger than Earth's. Consequently, the radiation experienced by Juno is among the most intense in the solar system.

Preliminary indications suggest that Juno entered safe mode while traversing the planet's closest radiation belts, which are characterized by particularly high radiation levels. This is not the first time Juno has encountered such an issue; the spacecraft has previously entered safe mode three times during past flybys, including during its second orbit around Jupiter in 2016.

Launched on August 5, 2011, Juno has been exploring Jupiter since arriving in July 2016. Its mission includes conducting close flybys of the planet and its moons. The recent flyby on April 4 was the 71st, with the next scheduled for May 7, which will also involve a close approach to Jupiter's moon Io.