WASHINGTON — It’s a road trip that could test the best of marriages: Mars.
A tycoon announced plans Wednesday to send a middle-aged couple on a privately built spaceship to slingshot around the red planet and come back home, hopefully with their bodies and marriage in one piece after 501 days of no-escape togetherness in a cramped capsule half the size of an RV.
Under the audacious but bare-bones plan, the spacecraft would blast off less than five years from now and pass within 100 miles of the Martian surface.
The cost was not disclosed, but outsiders put it at more than $1 billion.
The team of space veterans behind the project hasn’t quite figured out the technical details of the rocket they will use or the capsule the husband-and-wife astronauts will live in during the 16-month voyage.
‘‘This is not going to be an easy mission,’’ chief technical officer and potential crew member Taber MacCallum said. ‘‘We called it the Lewis and Clark trip to Mars.’’
The private, nonprofit project, called Inspiration Mars, will get initial money from NASA engineer-turned-multimillionaire investment consultant Dennis Tito, the first space tourist. The organizers hope to raise the rest through donations, advertising, and media partnerships.
NASA will not be involved.