The Karman Line

“No one will be looking for a floating sign that reads you are now entering the vacuum of space.”

I agree with that assertion, but where are the UFO's? Or a cameo appearance from Rod Serling floating in a space suit saying that you're now entering the Twilight Zone, or maybe the 2001 Space Odyssey fetus floating around, sucking on his thumb?

If you're really lucky you might see the Millenium Falcon zoom by. Was that Chewbacca waving at us from the cockpit?

But this is the sign we really need:

Have a safe and pleasant journey, and please visit the earth again, soon. Thank you, The tRump Organization, owner of Greenland and 99 percent of the mindshare of white supremacists, worldwide.