The positions of Saturn's eight brightest moons.
SatSat is a "progressive web app", meaning that you should be able to install it on the home screen of Android or iOS phones and tablets (look for "Add to Home Screen" in the Chrome or Safari menu).. It doesn't collect data or need any funky permissions, and shouldn't need to use the network at all once you have the app downloaded.
Satellite positions are approximate. This uses a somewhat kludgey method that gradually drifts. Positions last updated: 2003. (in 2019, I'm working on getting the positions updated.)