This guide will let you know how to get Gravitino Balls in No Man’s Sky.
Gravitino balls are only found on planets with high/aggressive sentinel activity and they are very easy to find on those planets. So first, you will need to find a planet with high or aggressive sentinel activity on it before anything.

If the system you’re in does not have a planet with high/aggressive sentinel activity on it, then you need to warp to new systems until you find one with a planet that has what you’re looking for on it.

Once you land on a planet with high sentinel activity, you have to use your analysis visor to look for yellow star symbols around the planet as some of them can be Gravitino balls.
