Mr Musk said in a message to accompany the photo: “Printed on the circuit board of a car in deep space.”
The tongue-in-cheek message reads “made on Earth by humans” and is bound to be helpful if to any extraterrestrials who encounter the car.
The Falcon Heavy became the most powerful operational rocket in the world after being launched from the Kennedy Space Centre at 3.45pm EST (8.45pm GMT).
Stunning images of the car heading away from Earth on its epic voyage while the car stereo plays David Bowie’s Space Oddity were seen by thousands on the launch lifestream.
The frozen car was shown in the vacuum of space with a dummy at the wheel to pilot it into its distant Mars orbit.
Another image showed the car with Australia in the rear-view mirror.
SpaceX said before the launch: “When Falcon Heavy lifts off, it will be the most powerful operational rocket in the world by a factor of two.
“With the ability to lift into orbit nearly 64 metric tons (141,000 lb) – a mass greater than a 737 jetliner loaded with passengers, crew, luggage, and fuel – Falcon Heavy can lift more than twice the payload of the next closest operational vehicle, the Delta IV Heavy, at one-third the cost.
“Falcon Heavy draws upon the proven heritage and reliability of Falcon 9.”
SpaceX founder Elon Musk teased that the successful mission will pave the way for future manned journeys but also admitted that he just wanted to spice things up a bit.
The South African billionaire said: “Test flights of new rockets usually contain mass simulators in the form of concrete or steel blocks. That seemed extremely boring.
“Of course, anything boring is terrible, especially companies, so we decided to send something unusual, something that made us feel.
“The payload will be an original Tesla Roadster, playing Space Oddity, on a billion year elliptic Mars orbit.”
The Falcon Heavy is a 20-story tall rocket with an impressive array of 27 engines and three Falcon 9 boosters.
The Falcon 9 is SpaceX’s signature reusable rocket and the space company successfully brought the boosters back to Earth after launch.
SpaceX tweeted: “Falcon Heavy side cores have landed at SpaceX’s Landing Zones 1 and 2.”