The Cassini spacecraft has been orbiting Saturn for about 20 years and its fuel is running out. No gas stations out there, so tomorrow, September 15, is its last day.

Instead of letting the gravitational pushes and pulls of Saturn, its moons and rings cause the satellite to crash into a pristine, scientifically valuable moon, the Jet Propulsion Laboratory engineers are sending it into the thick gas atmosphere of Saturn, where it will burn up.

Over the years, the Cassini instruments have answered many questions about the complex Saturn system and, of course, have popped up a bunch of new questions. Most recently, the flight path of the little spacecraft sent it through possibly dangerous areas between the rings of Saturn. At its speed, even a small particle could have disabled the craft's instruments.

But, it's still working and will make its final plunge into Saturn starting at about 2:30 a.m. Mountain Daylight Time Friday, September 15. Loss of signal is expected about 3:55 a.m.

Coverage will be "live," since it takes over an hour to send a signal back to Earth. That means actions at Saturn will have already happened by the time we get confirmation.

You can find more places to read, and watch at the JPL NASA Cassini Grand Finale website.