For any and all prowling around planets hunting down the wolves who drop down at warning be warned. If you are too fast to the next destination by pure luck and still have your previous ether key countdown active while you manage to kill the wolf the counter will not reset this greatly diminishing the time you have to find the fallen ether chest. This recently happened to me on Venus when I went straight from killing the dreg in the citadel only to get the chest and go to ember caves were some randoms had already brought the invisible captain down to half. I killed him with 5 seconds on my previous counter still active but instead of getting a new counter with 1min and 30sec I was left with my 5sec counter and even though the chest spawned a second away on sparrow by the time I saw it I had 3 seconds left. So as recap wait for your ether key to fade away completely before killing the next wolf