"Code of the lifemaker."
Let me explain. If we are to explore it will be with AI that will be automated, self replicating, multi duplicating, machines. If that has any possibility of working, and if there is any other life in the universe, it would already have been done and it would have hit every single star within our galaxy by now.
“If that has any possibility of working, and if there is any other life in the universe, it would already have been done and it would have hit every single star within our galaxy by now.”
That assumes the beings wanted to do as you described. Also who is to say aliens machines have not observed or even visited the Earth at some time in the past? Aliens might have been able to get what they need from their star system or adjacent star systems.
"Code of the lifemaker."
Let me explain.
Just because it hasn’t happened in this time period - as far as we know, and lets just say UFOs are some natural thing, how do you know that in the 4 billion odd years previous that your putative machines did not come here?
How do you know that others may use some form of travel we cannot even comprehend?
How do you know they didn’t just pop in to orbit 50 years ago, take a look and put out the quarantined sign?
How do you know if the war fleet massing in the Ort Cloud will spare us, given their weapons can strike from light years distant?
What makes you an expert on alien behavior and technology, given that aliens are alien?