Earlier on Friday, Musk also said the Falcon Heavy launch would come "next month" (meaning January) from Launch Pad 39A at Kennedy Space Center in Florida. The company may attempt a "static fire" test of the rocket's three cores and 27 engines on the launch pad this month. As the Falcon Heavy rocket has been oft-delayed, launch dates should not be taken too literally, but it does seem like the rocket and associated hardware are close to ready to fly.
Silly payloads are kind of a tradition for SpaceX. Earlier this year, Musk explained that, inspired by the suggestion of a friend and the British comedy group Monty Python's Cheese Shop sketch, the Dragon spacecraft's demonstration flight in 2010 carried among its cargo a giant wheel of French Gruyére cheese.
In this case, sending a Tesla to Mars (it may be this vehicle) would not only have panache, it would provide some cross promotion for Musk's other major company. Launching a Raodster would also send a message to NASA and those who fund the space agency—SpaceX's new rocket can reach Mars, and the privately developed booster could play a major role in any plans the agency has to send humans to the Moon. No private company has ever launched a spacecraft beyond low-Earth orbit, let alone to another planet.
"The launch of the biggest rocket since the US Moon booster is a game changer for our country's space exploration future and for national security," said Phil Larson, an assistant dean at the University of Colorado and a former SpaceX official. "The fact that development of such a capability is coming from US industry is a very positive sign for our economic competitiveness."