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SpaceMan in his Tesla Roadster (Photo: SpaceX)
SpaceMan in his Tesla Roadster. (Photo: SpaceX)

“I love the thought of a car drifting apparently endlessly through space and perhaps being discovered by an alien race millions of years in the future,” Elon Musk tweeted. But an unstable trajectory and radiation from the Sun will disintegrate the Roadster within a couple of centuries, argues graduate student Kiran Narayana Reddy.

The successful launch of Falcon Heavy was nothing short of a milestone, the Dramaturgy surrounding the launch was unprecedented and deserves to be placed alongside landing on the moon and the first Kitty Hawk flight in a pantheon of amazing aerospace accomplishments.

Just a decade or so ago, it was thought that space travel in any significant form required government funding and management. But Elon Musk proved that people with profit motive and daring to do truly great things are capable of stunning achievements.

It was a marketing masterstroke of such absurdity that it left many incredulous

The showmanship demonstrated when SpaceX executed its high profile launch is unrivalled. There was the payload of the falcon rocket: a Tesla vehicle piloted by a brave mannequin and pumping out David Bowie's Life on Mars. There was a dummy astronaut at the wheel. It was a marketing masterstroke of such absurdity that it left many incredulous: the beautiful images of a car in space will help Musk sell more cars. It was the sort of thing that stoked the imagination of young people everywhere. How much less exciting would the launch have been if its first payload was a meteorological satellite? By that act alone, Musk made space, science and engineering fun.

This distant traveller will explore the outer space in a heliocentric orbit between 0.99 and 1.7 times the distance between the Sun and Earth. But how long will it continue to orbit, and what will be the fate of our ‘autonaut’?

Contrary to the popular belief that the Roadster will orbit the Sun for millions of years, this isn‘t the case. The Roadster is now essentially a near-Earth object (NEO). Planets and asteroids in circular orbits stay out of each other’s way and are relatively stable, but the Roadster is in eccentric orbits that cross the orbits of the planets. This makes its trajectories very unstable.

The Falcon Heavy’s second stage will cross the orbits of Earth and Mars, and its trajectory will be affected by Jupiter‘s gravitational field. There is a small chance that it might strike Earth or Mars many thousands of years from now, though it’s so small that it will burn up in the atmosphere.

The biggest problem is that the Roadster and Starman largely constitute rubber, plastics, and carbon composites which consist of a long chain of organic molecules that include epoxy resins, polypropylene, polystyrene, polyvinyl chloride, nylon, and many others. These are what the carbon composite car body, the fabrics in the interior, the cushions in the seats, electrical insulation, and a myriad of fasteners, fairings, and adhesive compounds are made of. Starman and his suit are made almost entirely of organic polymers, and even the safety glass in the car's windscreen is a plastic laminate.

The car is being evenly baked like a rotisserie chicken

All of these, at this very moment, are being bombarded with super high levels of stellar radiation, as the sunlit areas heat to 127º C and the shaded areas plunge to -173º C. So the car is being evenly baked like a rotisserie chicken, as the vehicle orbits toward and away from the Sun, undergoing strong thermal stresses that will cause all manner of material fatigue.

So what will the Roadster look like in a few centuries? The most obvious thing will be that, largely comprised of carbon-carbon bonds and carbon-hydrogen bonds, its chemical attractions may falter under the intense energy from the radiation. As the bonds break, the car can literally fall apart. The rubber tyres on the wheels won't be there anymore either.

But, at end of the day, it was either the Roadster or a concrete brick. Can you blame them for wanting to have a little fun? After all, don't all physical objects eventually turn to dust? One thing is for sure, Musk won’t be getting invited to address any environmental summit in the near future for adding a $200k Autonaut to yonder outer space where we’ve created a giant garbage dump replete with huge hulks of rusting metal.

Kiran Narayana Reddy, Graduate Student Flight propulsion and performance, Delft University of Technology

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