An artist's conception of Cassini during its orbit insertion burn. The spacecraft would be moving up and to the right, having already passed through the rings once. Click on image for full size (31K JPEG) Image courtesy NASA/JPL.

The Cassini spacecraft will arrive at Saturn on June 30, 2004. Cassini's engine will make a critical 96-minute burn starting at 7:36 p.m. Pacific Time (10:36 p.m. EDT) on June 30. The burn will slow Cassini enough to be captured into orbit around Saturn.

During this Saturn Orbit Insertion (SOI) maneuver, Cassini will pass closer to Saturn than at any other time during its mission. At closest approach Cassini will zip by 19,980 km (12,427 miles) above Saturn's cloud tops. It will also pass through Saturn's rings twice, once before and once after the engine's burn. Cassini will dodge through a gap in the rings (between the F and G rings) in hopes of avoiding collisions with ring particles. It will also turn its main antenna dish forward to act as a shield for the rest of the spacecraft against hypervelocity impacts with dust particles in the rings during its ring passages. Cassini should get great images of the rings during these passes.

Cassini will use its 12 instruments to study Saturn, its rings, and its moons during the spacecraft's scheduled four-year mission in orbit around Saturn. Cassini also carries a smaller probe, named Huygens, which will land on the surface of Saturn's largest moon, Titan, in January 2005. Cassini was launched towards Saturn back in 1997.

We won't know whether Cassini's orbital insertion maneuvers went well until 84 minutes after they happen. That's because Saturn is currently 1.5 billion km (934 million miles), or 84 light minutes, from Earth, and radio signals from the spacecraft travel at the speed of light. The long communication lag means flight controllers cannot make any adjustments to Cassini during the SOI, so any improvisations Cassini must perform (in response to being jostled by a dust particle collision, for instance) during the SOI must be preprogrammed into its computer.

This is what an artist thinks Cassini might look like when it uses its rocket engine to slow down and go into orbit around Saturn. Click on image for full size (31K JPEG) Image courtesy NASA/JPL.

A spacecraft named Cassini will get to Saturn on June 30, 2004. Cassini's rocket engine will burn for 96 minutes to slow the robot spaceship down. If it works, Cassini will be captured into orbit around Saturn. Cassini was launched in 1997, so it has taken nearly seven years to complete its long journey to Saturn.

Cassini will orbit Saturn for at least four years. It will use its 12 instruments to study Saturn, its rings, and its moons. Cassini is also carrying a smaller probe named Huygens. Huygens will land on Titan, Saturn's largest moon, in January 2005.

Cassini will get its closest views of its entire mission of Saturn and of Saturn's rings during this first swing by the planet. In fact, Cassini will pass through the rings twice while braking into orbit. Cassini will turn its main antenna dish forward when it passes through the ring, to act as a shield against high-speed collisions with ring particles.

This picture shows what Cassini might look like near Saturn. Can you spot the blue flame of Cassini's small rocket engine? Click on image for full size (31K JPEG) Image courtesy NASA/JPL.

A robot spaceship is about to get to Saturn. The spaceship is named Cassini. Cassini is moving fast because it had a long way to travel to get to Saturn. Cassini will fire its rocket engine for 96 minutes on June 30, 2004. That will slow the spacecraft down. Then it will start to orbit Saturn.

Cassini will study Saturn, Saturn's rings, and Saturn's moons. It will study them for at least four years. It has 12 instruments that it will use to collect data and take pictures.

Cassini is also carrying a second, smaller spacecraft. That spacecraft is named Huygens. Huygens will land on Saturn's largest moon, Titan, in January 2005.

Cassini will fly very close to Saturn when it fires its engine and slows down. It will be the closest Cassini ever gets to Saturn. Cassini should get some great pictures of the planet! Cassini will also fly right through a gap in Saturn's rings!