Later, the ion engine is replaced with faster propulsion - a NERVA design nuclear engine.
Still later, some genius figures out that a SPACESHIP is not a STARSHIP, and everything goes back to the drawing boards.
STARSHIP Enterprise awaits in the very distant future - after all the homeless are fed and muslim outreach has reached its logical conclusion.
STARSHIP Enterprise in 2245 is an optimists wet dream ...
The year is 1736 and landing on the moon was an optimist's wet dream.
I'll give the STARSHIP forecast date the benefit of the doubt.