Photo: NASA/JPL-Caltech
Controllers and scientists must wait until Thursday to hear from Cassini, the BBC reports.
The probe was due early on Wednesday to make the first of 22 dives in between Saturn’s cloudtops and the inner edge of its spectacular rings.
The daredevil flights are designed to gather pictures and other science data of unprecedented resolution.
But Cassini was out of radio contact for the duration of the plunge and is not scheduled to re-establish communications for another day.
Because the probe was moving so fast – at over 110,000km/h – there was some risk attached to flying through the ring plane.
An impact with even a tiny ice or rock particle at that velocity could do a lot of damage, and so the decision was made to point Cassini’s big antenna in the direction of travel, to act as a shield.
But, of course, that meant it could not also then talk to Earth at the same time.
Assuming all goes well, 21 similar dives will be made over the course of the next five months before the probe dumps itself in the atmosphere of Saturn. With so little fuel left in its tanks, Cassini cannot continue its mission for much longer.
The US space agency (Nasa) is calling the gap-runs the “grand finale”, in part because of their ambition. They promise pictures of unparalleled resolution and science data that finally unlocks key puzzles about the make-up and history of this huge world.
“We’re going to top off this mission with a lot of new measurements – some amazing new data,” said Athena Coustenis from the Paris Observatory in Meudon, France.
“We’re expecting to get the composition, structure and dynamics of the atmosphere, and fantastic information about the rings,” she told the BBC.
A key objective is to determine the mass and therefore the age of the rings. The more massive they are, the older they are likely to be – perhaps as old as Saturn itself.
Scientists will do this by studying how the velocity of the probe is altered as it flies through the gravity field generated by the planet and the great encircling bands of ice.