The US government considered a program to reverse-engineer potential alien technology if found, a Department of Defense ...

And what would it take for alien engineers to traverse vast distances to send probes or visit Earth from other solar systems? Explore the evidence, as astrophysicists and engineers use new ...

which show the creation of the Xenomorphs by the enigmatic alien Engineers and the megalomaniacal android David. Suffice to say, David never brought any to Earth either.