NASA Waits on Cassini Radio Contact From Saturn

As Cassini wraps up its 13-year mission in Saturn's system, scientists are preparing for the spacecraft's final burst of observations in the never-before-explored region between the planet and its inner rings. Cassini crossed Saturn's ring plane for the first time yesterday (April 26). Next, after a series of 22 orbits and close flybys of the rings, the robotic probe will take a death dive into the planet's atmosphere on Sept. 15.

Cassini Cassini

"Because that gap is a region no spacecraft has ever explored, Cassini will use its dish-shaped high-gain antenna (13 feet or 4 meters across) as a protective shield while passing through the ring plane," NASA says. "No particles larger than smoke particles are expected, but the precautionary measure is being taken on the first dive."

Cassini Saturn

The final flybys will be a "dangerous moment for the mission," said Luciano Iess, a Cassini team member from La Sapienza University in Italy. The spacecraft will be moving at a speed of about 30 kilometers per second, or 67,000 mph (42,000 km/h), passing rocks and tiny particles as it grazes the ring planes. If those orbits are successful, scientists will have a chance to examine the material in Saturn's mostly water-ice rings in greater detail than ever before, which could help them determine the mass and age of the rings.

Cassini Saturn  

“What a spectacular end to a spectacular mission,” Jim Green, NASA’s planetary science division director, told CBS. “I feel a little sad in many ways that Cassini’s discoveries will end. But I’m also quite optimistic that we’re going to discover some new and really exciting science as we probe the region we’ve never probed before.”

Cassini will be out of contact with Earth during the dives because of its antenna orientation, NASA said. But once communication is regained, it will start dispatching information back to Earth.