NASA’s Cassini spacecraft has completed its first daring dive through the narrow gap between Saturn and its rings.
By Lola Gayle, Editor-at-large
After a daring and successful dive through the narrow gap between the planet Saturn and its rings on Wednesday, April 26, 2017, NASA’s Cassini spacecraft is now communicating once again with Earth.
“In the grandest tradition of exploration, NASA’s Cassini spacecraft has once again blazed a trail, showing us new wonders and demonstrating where our curiosity can take us if we dare,” said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington.
During its dive through the gap, Cassini came within about 1,900 miles (3,000 kilometers) of Saturn’s cloud tops. At this height, the air pressure is roughly 1 bar — comparable to the atmospheric pressure of Earth at sea level. The spacecraft also came within about 200 miles (300 kilometers) of the innermost visible edge of the rings.
Because this region has never been visited by spacecraft, mission managers took extra precautions to keep Cassini safe from harm.
“No spacecraft has ever been this close to Saturn before. We could only rely on predictions, based on our experience with Saturn’s other rings, of what we thought this gap between the rings and Saturn would be like,” said Cassini Project Manager Earl Maize of NASA’s Jet Propulsion Laboratory in Pasadena, California. “I am delighted to report that Cassini shot through the gap just as we planned and has come out the other side in excellent shape.”
The gap Maize referred to is about 1,500 miles (2,000 kilometers) wide, and models suggest that any potential ring particles would be tiny — about the size of smoke particles. As it crossed the gap, Cassini was moving at speeds of about 77,000 mph (124,000 kph) relative to Saturn, so small particles hitting a sensitive area could potentially have disabled the spacecraft.
Because of this, Cassini was instructed to use its high-gain antenna as a shield, leaving it unable to contact Earth during the ring-plane crossing during the roughly 20-hour excursion.
This maneuver is an integral part of what mission planners are calling its “Grand Finale.” During this final chapter, Cassini will loop around Saturn about once per week, making a total of 22 dives between the rings and the planet. Cassini is scheduled to make a second dive through the gap on May 2, 2017.
For now, the spacecraft is in the process of beaming back all the data collected during the first dive via NASA’s Deep Space Network (DSN) Goldstone Complex in California’s Mojave Desert. This data will help engineers understand if and how they will need to protect the spacecraft on its future ring-plane crossings.
In the end, Cassini will plunge into Saturn’s atmosphere on Sept. 15, 2017, thereby ending its long and successful mission. Cassini has been touring the Saturnian system since its arrival in 2004. During that time it has made several dramatic discoveries, including a global ocean within Enceladus and liquid methane seas on Titan.
More of my articles about Cassini on STEAMRegister. com.