Cassini’s Final Hours by the Numbers

By John Wenz | September 13, 2017 4:31 pm
Cassini spent part of its Grand Finale diving through the gap between Saturn and its rings, taking observations that had never before been attempted. (Credit: JPL/Caltech)

Cassini spent part of its Grand Finale diving through the gap between Saturn and its rings, taking observations that had never before been attempted. (Credit: JPL/Caltech)

The Cassini probe has given us a spectacular view of the Saturn system over the 13 years it’s been there. In that time, it’s opened up untold wonders of our second-largest planet and its 62 spectacular moons. Here are a few big-to-small numbers to know as Cassini prepares for self-destruction:

4.9 billion miles: the total distance traversed by Cassini in the Saturn system since 2004

635 gigabytes: the total volume of data sent back by Cassini

615 watts: the amount of power Cassini currently produces

512 kilobytes: the amount of onboard storage capacity on Cassini

294: the number of times Cassini flew by Titan and received a gravity boost, including a few skims through the upper atmosphere

Plutonium 238: Cassini’s power source

24: approximate number of moons visited by Cassini (out of 62)

19 years, 1 month: Cassini’s total time in space, from launch until end of mission

14 hours: the time between the last image from Cassini and its crash

13 years: the time Cassini has spent at Saturn

6: the number of moons discovered by Cassini

4:55 a.m. PDT: when Cassini will enter Saturn’s atmosphere and begin to break up

2 minutes: the amount of time it will take Saturn to rip Cassini apart

1 hour, 23 minutes: the time it takes for a signal from Cassini to reach Earth due to the vast distance between us and Saturn

1 megapixel: the resolution of Cassini’s camera

1 in a million: the chance that a fuel-less, ill-controlled Cassini might have smashed into Enceladus and potentially contaminated it


[This post originally appeared on]

  • Uncle Al

    512 kilobytes: the amount of onboard storage capacity on Cassini
    1 megapixel: the resolution of Cassini’s camera

    There’s your problem.

    • Mumu Gheghe

      512 KB seems rather small indeed, but it’s not necessarily a problem: 1 Megapixel = 128 KB. Add PNG (or JPG) compression to that and you end up being able to store maybe even 10 snapshots in 512 KB. Memory consumes power whether it’s being used or not. And since it’s “onboard _storage_” my guess is that the OS has it’s own memory space, that is, these 512 KB are not shared, are just for data storage.

      • Dan Sutton

        Actually, I think it’s 512 Kb total. Remember, the thing is 20 years old. But I have a feeling it has some backing store as well: a disk or something like that. It does buffer images and then send them back as a batch: It has to because half the time, Earth is occluded from it by Saturn, and the signal can’t pass.

    • Mumu Gheghe

      They won’t let me use URLs here. I googled a little for the “cassini huygens onboard storage” keywords and the third result is a PDF on a government site with Cassini specs. The memory storage is 4 Gbits, that would be 512 MB.

    • NV Dude

      Blah blah blah

  • Mauricio Micoski

    Good bye, Cassini! Very well done!

  • Lawdy! Lawdy! Lawdy!

    Why not try to land it on a moon?

    • NV Dude

      Its already been done

  • Fike Rehman

    Why did they decide to crash it on Saturn rather then Titan or Enceladus?

    • Dan Sutton

      Because Saturn will burn it up. They’re worried that if it hits a moon (airless) it’ll contaminate it with bacteria from Earth. Enceladus has a subsurface ocean, and they don’t want it being contaminated with Earth life, in case it already has life of its own.

      • Fike Rehman

        Thank you…good information

  • paul johnson

    What a fantastic project Cassini turned out to be. I doubt the designers and constructors realized just how wonderful this little spacecraft would be. How important their project would become and the vast volumes of scientific data it would generate. It is sad to see it end. I have followed it’s mission with awe and admiration. Goodbye Cassini old friend.


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