Our fifth attempt at first contact was near Roswell in 1947.
It was not a success. The United States Government didn't want us sharing our technology with anyone else but them.
After consulting with our leaders, we decided to shut the memories
down of all those contacted.
False memories of an "alien crash landing" were implanted into their
minds. Some affirmed these memories and some negated them.
Doesn't your own reason tell you that if we have the technology
to reach Earth then we have the technology to safely land here?