![]() The camera will also take some of the highest-resolution images yet of Saturn’s A ring, and will try to capture ring features known as propellers, straw, spiral waves, and ringlets. In this orbit, Cassini’s imaging camera will get its best views yet of Saturn’s moon Pandora, including the first views of the moon’s northern hemisphere. Scientists will use data from the two instruments during this pass to calibrate them for the first ring-plane crossing of Cassini’s Grand Finale Orbits, which will happen during Rev 271. As part of the exercise, the spacecraft’s Radio and Plasma Wave Science instrument will “listen” to particle collisions, and the Cosmic Dust Analyzer will scoop up and analyze particles. As a result, most instruments should be relatively safe from ring particles.Ĭassini will practice that positioning during its ring-plane crossing on Rev 252. So during the first Grand Finale Orbit, the dish will serve as a shield when Cassini punctures Saturn’s ring plane at thousands of miles per hour. Only a few of Cassini’s instruments extend beyond the diameter of the spacecraft’s high-gain antenna. To minimize the hazard from ring particles, the spacecraft will orient its high-gain antenna toward the direction the spacecraft is traveling (called RAM position) like a snow plow. Inward and outward from Saturn’s dense, visible rings, a less-dense population of hard-to-see particles reside in the ring plane and can pose a hazard to the spacecraft. Cassini will take advantage of the alignment by using its radio science instrument to study that interference for the benefit of future missions.Ĭassini will also practice for its Grand Finale Orbits, in which the spacecraft passes in the unexplored narrow space between the planet and its rings. ![]() The sun will be between Earth and Saturn in what’s called a conjunction, during which the sun’s solar wind/plasma interferes with normal radio communications and radio science experiments. To calibrate Cassini’s magnetometer for later, the spacecraft will roll for part of its second ring-grazing orbit. On this ring-grazing orbit, Cassini will cross Saturn’s ring plane within 6,867 miles (11,051 kilometers) of Saturn’s F ring. This orbit also features observations of Enceladus' active south pole and search the moon Tethys for more observations of its mysterious red-striped regions. Cassini’s Visual and Infrared Mapping Spectrometer will make a nine-hour movie of Saturn's north pole, and several instruments will measure the boundaries of Saturn's upper atmosphere, a critical observation because future orbits will take Cassini down into the atmosphere for direct sampling. Cassini will also study Saturn's northern hemisphere and atmosphere. ![]() On Cassini’s first Ring-Grazing dive past Saturn's F ring, the spacecraft’s Radio Science instrument transmits a radio signal to Earth through Saturn’s rings in a uniquely long sweep. The Titan flyby marks the end of Cassini’s Ring-Grazing Orbits, and sets the stage for the mission’s Grand Finale to begin.įor the complete list of F Ring orbits, visit our Ring-Grazing Orbits Quick Reference. The spacecraft will repeat that dive once per week until the end of the mission in September. The flyby alters Cassini's orbit so that, instead of flying just outside of the rings, the spacecraft will shoot through the narrow space between Saturn’s upper atmosphere and its innermost rings. The spacecraft will use Titan’s gravity as a pivot point to change the shape of Cassini’s orbit in a fateful way - from this point forward, the spacecraft's orbit will eventually impact Saturn, even if controllers on Earth take no further action. Closest approach to Titan occurs at 3:26 a.m. Cassini will pass within about 600 miles (about 1,000 kilometers) of the Mercury-sized moon on Saturday, April 22.
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