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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Jupiter Icy Moons Explorer | 2/4 | https://en.wikipedia.org/wiki/Jupiter_Icy_Moons_Explorer | reference | science, encyclopedia | 2026-05-05T13:18:32.966259+00:00 | kb-cron |
In August 2024, Juice performed its first gravity assist when it flew by the Moon and then Earth, becoming the first ever spacecraft to perform such maneuver using both bodies. The closest approach to the Moon happened at 21:15 UTC on 19 August. This increased the spacecraft's speed by 0.9 km/s relative to the Sun, sending it towards Earth. The closest approach to Earth happened at 21:56 UTC on 20 August. This reduced the spacecraft's speed by 4.8 km/s relative to the Sun, sending it towards Venus for the next gravity assist planned for August 2025. This double gravity assist saved the spacecraft up to 150 kg of fuel and deflected it by an angle of 100° compared to its path before the flyby. During this maneuver, Juice tested many of its scientific instruments. All 10 instruments were active during the Moon flyby, and eight during the Earth flyby. The JANUS camera took high-resolution images of the Moon and Earth. The MAJIS and SWI instruments detected the expected chemical signatures of habitability on Earth and MAJIS also provided information-rich temperature maps of Earth. Two sensors of the Particle Environment Package (PEP) took pictures and in situ measurements of the charged particle cloud surrounding Earth. The RIME radar sounder captured a radargram image of the patch of the lunar surface that is also visible in the famous Earthrise photo, taken in 1968 during the Apollo 8 mission.
=== Venus flyby === On 16 July 2025, during a time-sensitive period before the planned Venus flyby, Juice experienced a communication anomaly that temporarily severed the spacecraft's contact with Earth. After almost 20 hours of recovery efforts, ESOC and Airbus managed to resolve the issue and identified its root cause related to a scheduled restart of the spacecraft's internal timer. Plans for the flyby remained unchanged and Juice successfully flew by Venus on 31 August 2025, with the closest approach of 5,088 km above Venus's surface at 05:28 UTC, performing a gravity assist maneuver that increased its velocity by 5.1 km/s and sent it towards its second Earth flyby planned for September 2026. Due to thermal constraints (solar flux of 3,000 W/m2 near Venus versus 50 W/m2 near Jupiter), no imaging or scientific observations were planned for the Venus flyby and the spacecraft used its high-gain antenna as a thermal shield, pointing it toward the Sun.
=== 3I/ATLAS observations ===
The interstellar comet 3I/ATLAS, discovered in July 2025 as only the third known interstellar object in the Solar System, made its closest approach to the Sun in October 2025. However, this part of its trajectory, when it was expected to show strong cometary activity, was not visible from Earth-based telescopes as it occurred on the other side of the Sun. In September 2025, ESA expected that of all its interplanetary spacecraft, Juice would have the best conditions for observing the object during its close approach to the Sun. ESA commanded Juice to attempt observing 3I/ATLAS in November 2025, at a distance of 0.428 AU, using its cameras, spectrometers, and a particle sensor. ESA was also considering coordinating ultraviolet spectrograph observations with NASA's Europa Clipper. Because Juice had to point its high-gain antenna towards the Sun to act as a heat shield during its travel through the inner Solar System, known as "hot-cruise phase", the data from these observations were not expected to reach Earth before February 2026. The commands for the observations were prepared at ESOC. The observations were conducted between 2 and 25 November 2025. Thermal constraints were expected to limit the observations for no more than 30 minutes per day with the exception of the Particle Environment Package (PEP) which was commanded to operate for twelve days straight. The final observation schedule included six 45-minute slots and one final 4-hour slot. The observations generated 11.18 Gbits of data. The closest approach between the comet and the spacecraft happened on 4 November 2025. In early December 2025, ESA released a preliminary picture of 3I/ATLAS taken on 2 November 2025 by Juice's Navigation Camera (NavCam). The photo included the comet's coma as well as the plasma and dust tails. The spacecraft entered the "cold-cruise phase" of its flight in mid-January 2026 and the observation data from five instruments—JANUS, MAJIS, SWI, PEP, and UVS—arrived on Earth in two 11-hour passes on 17 and 20 February 2026 via ESTRACK's antennas in New Norcia and Malargüe. The 3I/ATLAS observation campaign officially ended on 20 February 2026 at 18:21 UTC. ESA released the first one of more than 120 images of 3I/ATLAS taken by the JANUS camera system on 26 February 2026.
On 2 April 2026, ESA released first preliminary scientific results from the observations. The MAJIS instrument measured that on 2 November 2025, 3I/ATLAS was releasing 2000 kg of water per second and this amount hadn't diminished significantly in observations 10 days later, on 12 November 2025. The SWI instrument detected that most of the water was being released from the Sun-facing side of the comet and a substantial part of it came from icy dust grains of the coma, and not directly from the nucleus. The UVS images also revealed that the gas and dust from the comet stretched at least 5 million km from the nucleus. The JANUS images revealed faint structures within the comet's coma and two tails.
=== Cruise towards the 2nd Earth flyby === In early March 2026, when Juice no longer needed to use its high‑gain antenna as a Sun shield, ESOC performed a series of planned pointing checkout tests on the spacecraft's instruments, software updates, operations exercises, and commissioning activities.
== Trajectory ==
Following the launch, multiple gravity assists are needed to put Juice on a trajectory to Jupiter: