Forget all the Mars rovers. I really couldn't care less whether anyone gets to mars in my lifetime. That won't change much of anything. I don't want to hear the decades of debate on whether Mars had microbes once upon a time. I want a telescope to find an atmosphere proving that jungles exist on other planets today. I want them to find a planet so thick with life that nobody can deny it. I want Degobah. That will expand our perspective as a species.

> I want a telescope to find an atmosphere proving that jungles exist on other planets today.

In this case you would be most interested in NASA’s planned LUVOIR telescope[1]. In an interview the gentleman in charge of preliminary design claims that it will answer the question with a 95% certainty.[2]

[1] https://asd.gsfc.nasa.gov/luvoir/science/

[2] https://youtu.be/MMQvjpcbkBU

Here is the interview link with timestamp for the pertinent part: https://youtu.be/MMQvjpcbkBU?t=32m52s

But if we can’t work any of that out for our nearest neighbour, how are we going to reliably do this for planets that are many light years away?

We have worked it out. I can say with 100% certainty that there are no jungles on Mars. Nothing above pond scum is alive there today.