La mission Juno de la NASA en orbite autour de Jupiter a rendu un ensemble fabuleux de nouvelles images après son passage mensuel proche des sommets nuageux de la planète géante.
NASA’s Juno spacecraft orbiting Jupiter has returned another spectacular set of images of the giant planet as it shines brightly as the “Christmas Star” or “Star of Bethlehem” in Earth’s night sky.
In an elliptical orbit of Jupiter since July 2016, Juno dipped close to the planet’s cloud tops on November 22, its 56th perijove. It took images using JunoCAM, its two-megapixel camera, while traveling at around 130,000 mph (209,000 kph).
The raw data takes about 34 light-minutes to reach Earth from Juno as a radio transmission. In the days since citizen scientists have transformed the raw data into the spectacular images you see here. That’s despite Juno spinning as it orbits, producing strips of images that have to be pieced together.
Juno is the first mission to orbit an outer planet from pole to pole. Between each perijove, its elliptical orbit takes it far from Jupiter only to swing just a few thousand miles from its cloud tops at the planet’s poles.
Jupiter’s intense radiation belts make it necessary for Juno to be armored. It’s fitted with a titanium radiation vault to protect its sensitive science instruments.
Those instruments include a magnetometer, a gravity science system and a microwave radiometer, which allows it to measure Jupiter’s magnetic and gravitational fields, as well as its atmospheric temperature, pressure, and composition.
Even Juno’s communications system can be used for science. As well as to communicate with NASA and send back fabulous images such as the ones you see here, the space agency’s Deep Space Network antennas track Juno’s radio signal and measure how fast it’s moving.
Even tiny changes in Juno’s velocity as it orbits Jupiter—even a 0.01 millimeter per second variation—reveal precisely how Jupiter’s gravity field works. That’s useful for understanding more about the giant planet’s atmosphere.
Some of the most crucial scientific findings from the Juno mission include finding abundant water near the planet’s equator, detecting lightning in Jupiter’s clouds and discovering the cause of Jupiter’s x-ray aurorae.
During its 55th perijove in October, Juno passed just 7,270 miles (11,700 kilometers) from Jupiter’s volcanic moon Io, the closest pass since NASA’s Galileo probe imaged the volcanic moon in October 2001.
Juno, which orbits Jupiter every 38 days, will go one better just before its 57th perijove on December 30 when it will get to within a mere 930 miles (1,500 kilometers) of Io. It’s expected to send back the best images ever obtained of the tortured moon.
Wishing you clear skies and wide eyes.
French