Aliens, if they do exist, won't be coming here anytime soon. There is nothing about the Earth, perched as it is on an outer spiral arm of our galaxy, that would be of the slightest interest in a civilization capable of Interstellar travel. There is nothing in science that says alien life form can't exist, or has to exist. It's pure speculation.
Space exploration, on the other hand, is dead for any foreseeable future. Begun as a very expensive Cold War stunt, the cost alone prohibits any serious exploration of space. We simply don't possess the technology for cost-effective space exploration.
Even our most cost-effective launch vehicle (Falcon Heavy) promises (still unproven) a cost per KG to LEO (the wading pool of space) of $1100 . One thousand one-hundred dollars for every bottle of water. $230,000 for a single astronaut in his space suit.
Now, take that same launch vehicle and shoot it to Mars -- the price per KG of that bottle of water 'skyrockets' to $4,177. The cost of a single astronaut by our cheapest launch vehicle towards Mars (one direction only), nearly 1 MILLION dollars.
