I've got a puzzle for you to solve,
Like always, in three parts.
So start those engines, let those gears revolve
And let's let the puzzling start
My prefix is a common action
You might do it every day.
It's key to our communication,
Though if you can't, there's another way.
As seconds go by, the clock goes "tick!"
And the hands get farther apart
And the secret of my infix will finally click
When you find clock's action's second part.
My suffix is a friendly guy
He always says "hello"
While he drops out of Low Lunar Orbit
In which he'll frequently go.
As for my whole, that's a quite tragic tale.
One which we'll all someday know
When those who are there for you finally fail
Into my clutches you'll go.
What am I?