Red Skull ties with a rope the Capitan America to a rocket when it go to take off.

Then, when the the rocket takes off... land in the north pole... get frost.... pass 50 years in the ice... the Capitan wakes up and... he got her shield!

It looks like The Skull got a moment of kindness, because puts the shield of the Capitan in the rocket too.(Just in case)

"Is not a Capitan America, if do not have a shield"