If we knew exactly what to look for, DNA, chlorophyll, hemoglobin, maybe. But a life form that might be totally different rom ours, even if it was water/carbon based? Even a fully equipped automated lab could not do that.

Of course, a tiny camera might easily see a jellyfish or a trilobite, but a totally different life chemistry in a microorganism would require a sample return and a fully equipped lab on earth, and even then, it would require that the alien life evidence survived the return trip to earth.

A large muticellular animal or plant would be obvious to even the most simple sensor, like a TV camera. But a tiny cell, or its chemical tracers, especially one representing a totally alien biology, is hard to search for unless you already know something about its metabolism.

As for those "apps", forget it. You can't find life with software, you need a lab, and preferably, one equipped with a team of biologists. As Emily Dickinson pointed out (Granted, in a different context).

"Faith" is a fine invention when Gentlemen can see -- But Microscopes are prudent In an Emergency.

I was at work when the Viking landers first landed on the planet, and I was listening to the news from NASA over the radio in our lab. The announcer mentioned, as a joke; "Well, lets see if the first picture we see is of a bush or a bug." I missed the first part of his comment, and for a brief moment I thought all my hopes had been rewarded! But alas, here it is, half a century later, and in spite of some very good pictures we still don't know if there has ever been any life on Mars.