By Anna Kayser
Cassini, a NASA spacecraft orbiting Saturn, has been redirected, and experts at the University of Iowa are part of that discovery.
UI scientists helped to build part of Cassini. Their main focus was on the Radio and Plasma Wave System instrument of the spacecraft. The instrument measures radio and plasma waves as well as understands the processes in Saturn’s moons and atmosphere.
In April 2017, the spacecraft will move even closer to Saturn by moving through gaps between the rings of Saturn, said George Hospodarsky, a UI physics/astronomy associate research scientist and the lead operational planner on the project.
The rings are “pieces of comets, asteroids, or shattered moons that broke up before they reached the planet,” according to the NASA website.
On Sept. 15, 2017, Cassini will then enter Saturn’s atmosphere and act somewhat like a meteor burning up as part of the planetary-protection requirement by NASA. The protection is the practice of protecting Solar System bodies — planets, moons, comets, and asteroids — from contamination by Earth life and protecting Earth from possible life forms that may be returned from other Solar System bodies, according to NASA.
“We’re especially excited for April 26, 2017, when Cassini will thread the needle just above Saturn’s atmosphere and just below Saturn’s giant ring system for the very first time,” stated Bill Kurth, a UI physics/astronomy research scientist and the principal investigator of the project.
Kurth said Cassini executed a close flyby Saturn’s moon, Titan, which then switched its course. The spacecraft was brought into a ring grazing orbit just outside the F-ring of Saturn.
Scientists have detected hundreds of dust particles per second, along with the electromagnetic waves in space and planetary radio emissions. They also are looking for the interactions between the rings and Saturn.
Kurth said one of Saturn’s moons, Iapetus, could have water on it. If the Cassini were to crash into the moon, he said, it could dissipate some water particles or contaminate the habitat there, essentially ruining any future discoveries. NASA’s protection requirement was created to protect possible habitable planets, so no particles from a spacecraft could interfere with them.
Hospodarsky said the Cassini will take systematic measurements as well as pictures of storms and the atmosphere of Saturn.
“Basically, the project is in the process of getting ready for the end of the mission or what is known as the ‘grand finale,’ ” he said.
Linda Spilker, the Cassini Project scientist at the Jet Propulsion Lab in Pasadena, California, said the Radio and Plasma Wave System instrument will be key to understanding the particles in the gaps of Saturn’s rings. When Cassini flies through the F-ring in April, she said, it will use a dish to shield itself from the particles, and its antennas will help measure the particle hits.
In addition to collecting measurements, the instrument also helps NASA understand the magnetosphere of Saturn. The magnetosphere is caused through Saturn’s magnetic field, which is the second largest in the solar system.
“The scientists at the University of Iowa have helped us to better understand the complexity of Saturn’s magnetic bubble,” Spilker said.
The Cassini project began in July 2004 and will end after 17 years orbiting Saturn.
