1 of 4
Space Science Institute via AP, NASA/JPL-Caltech
This undated photo made available by NASA shows one of Saturn's moons, Mimas, dwarfed by the planet's rings. Launched in 1997, Cassini reached Saturn in 2004 and has been exploring it from orbit ever since. Cassini’s fuel tank is almost empty, so NASA has opted for a risky, but science-rich grand finale.

CAPE CANAVERAL, Fla. — NASA's Cassini spacecraft has ventured into the never-before-explored region between Saturn and its rings.

But flight controllers won't know how everything went until Thursday when they are back in touch with the craft.

Cassini was out of radio contact with Earth early Wednesday as it became the first spacecraft to enter the gap between Saturn and its rings. That's because its big dish antenna was maneuvered face forward to protect science instruments from potentially damaging ring particles.

If Cassini survives this first round, it will make 21 more crossings before its demise in September.

Launched in 1997, Cassini has been orbiting Saturn since 2004. Because the fuel tank is practically empty, NASA decided on one last dangerous, but science-rich adventure.