2. The species have overpopulated their home planet and need a new home. Hmm, that sounds interesting. Still, before I can sanction your budget of gazillion alien dollar space mission, I would ask you to consider populating the neighbouring planets first. If you were an earthling, I would ask you to consider Mars and Moon first. Next, I would show you Titan and Europa. I will even urge you to make space settlements, which can harness the energy of your Sun, than straightway giving a nod to your funky mission of populating an already populated alien planet. Not only a few light years ride is a tremendous deterrent, but you have also to consider the resistance your species will face from native populations and their pathogens. Is it really worth the risk?
3. What if the sun of their planet is dying? Yes, then you surely need a new home planet and a new sun. The journey is one way ticket and your species status quo is royally birched. In such a scenario, the story does look promising and possible. You surly will need to move with all your population in colossal spaceships and won’t mind generation wide travels. In such a case earth and its Sun could be to your liking and I have no doubt about it. You could hide your spaceship in the Asteroid belts and keep on sending scout missions to earth as UFOs. That does make sense. However, one problem, should you be not communicating with your UFOs from your mother ship? Why we earthlings don’t listen anything at all? Two possibilities, one you are not there at all. Second, we don’t know what to listen to.Hay, anybody down here on earth listening to me?
4. You are interested in basic scientific knowledge to lunch UFOs to earth. Nobody is going to sanction your mission. It does not have any profitable outcome. Getting answers will take ages for you. Of course, you won’t be discouraged. You will be asked to use optical and radio telescopic methods to carry out your search. Still, a nod for a manned mission seems improbable, until you prove that earth and earthlings are hospitable.
What would do you say??