A Tesla Model X On Mars Would Require A Few Changes
December 9th, 2017 Michael Barnard
Elon Musk recently decided to taunt the world with the delightful idea of
sending his original Tesla Roadster into orbit around Mars playing Space
Oddity on its stereo.
This led to a Quora question and resultant answer by the awesome Sierra
Spaulding. In turn, that led to a discussion of what would be required to
run a Tesla on Mars. Of course, this was an excuse for me to ask the Quora
hivemind the question: What engineering changes would be required to make it
possible for a Tesla Model X to run on Mars? After all, it will take more
than just putting acrylic paint on canvas as the artist who painted this
prescient painting did.
It was interesting to read what these deeply educated and insightful people
contributed, in addition to Sierra’s comments in various places. So, what
did they have to say?
At -120 degrees Celsius, most of the rubber bits of Teslas would fail. The
biggest concern here would be the tires of course. They just won’t cut it.
All of the liquids would freeze. And some of the metal bits would become so
brittle that they would just fail. And then there is battery temperature.
Tesla batteries like human survivable temperatures and fail rapidly if they
are really hot or cold. Of course, there’s the problem of human survival in
a Mars Tesla. Heat and oxygen are needed. The Model X will be seriously
bulked by insulation. But, of course, all of these problems are often bigger
for internal combustion engines. More hoses, liquids, and the like.
The atmospheric pressure on Mar is about 0.6% of Earth at sea level.
Obviously, the tires would likely just pop, but since they’d be brittle from
cold anyway, it’s a double whammy. What’s more interesting is that the
batteries are designed to function in a certain pressure differential. With
Mars’ pressure, the batteries would likely just pop. The air suspension
would be hosed too. Oh, what about the air bags! Of course, you have a
choice of pressurizing the cabin or remaining in pressurized suits for your
joy ride on the Red Planet.
Ain’t no roads on Mars
Yeah, Teslas were designed assuming smooth, silky tarmac. While there are
people who use Model Xs on dirt roads and the like, no one pretends it’s a
hardcore off-road machine. Despite the painting, roads don’t exist on Mars
and won’t for a long time. Dust, holes, and stones forever. 21″ low-profile
wheels aren’t going to do much good there. It’s likely that much larger
diameter and larger width wheels would be required to ensure the car doesn’t
disappear into a dust bowl. Something like the Mars Rover wheel, seen here
in a size-multiplying perspective, would be required. The Model X would
either have to be jacked up or have its axles extended to fit the right
wheels, and getting jacked up would be required in any event. Of course,
that would introduce the need for a ladder.
No Tesla roadside assistance
Right now, Tesla Model X owners receive bespoke service. Well-trained
service people show up with the right vehicle, tools, and equipment to fix
their expensive car when it breaks down or to carry it away for servicing.
It will be a while before the equivalent service appears on Mars. This means
finicky things are likely to go the way of the dodo bird. Automatically
opening doors? More likely a simple and robust mechanical system that is
impervious to the very fine Martian dust. Delicately opening falcon-wing
doors? Maybe not.
Different usage model
The Tesla Model X is a people mover with the ability to tow relatively
low-weight trailers and put in some luggage or skis. On Mars, grocery
shopping, commuting, and heading to the beach to kitesurf aren’t going to be
top of mind. For decades, Mars would be a working colony, struggling to
survive and in definite need of the cavernous space inside a Model X for
things other than bucket seats. Rip those out and put in fold-down benches
along the side for passengers and leave the middle open to throw useful
stuff in, like solar panels.
No Ludicrous Mode for a while
Limited solar and no tarmac means conserving energy and bad traction.
Peeling out in one of Tesla’s nuttier modes won’t be necessary. In fact, the
Earth expectation of being able to travel 400 kilometers at 120 km/h is out
the window entirely. I’d be surprised if a car reaches 100 km/h on Mars in
the first 40 years of colonization outside of falling off a high cliff. So,
the engine control systems will all be tuned to lower speeds.
Well, at least not as it exists today. The first DARPA challenge in 2004
that kicked off the current glut of companies claiming that they have the
secret sauce was actually an off-road course. But even then, GPS existed.
The first thing that would be required for any somewhat autonomous driving
would be a string of GPS geosynchronous satellites, and that likely won’t be
a priority of the first decade. Lots of people have been talking about GPS
satellites for Mars, including discussions about whether it’s even possible
to do serious exploration and colonization without them, but they likely
won’t be there Day 1. Back to old-fashioned ways of establishing position.
There will be orbiting satellites that can feed high-definition images of
position and destinations so that routes can be planned, but that’s well
below the information level suitable for a vehicle to drive itself. There
will undoubtedly be some driver assistance features to prevent people from
driving off cliffs and the like, but Lane Control won’t be needed.
International space law and bugs
Did you know that everything that lands on Mars has to be sterile?
Scientists and the people who make the rules about other planets are very
worried about Earth microbes contaminating alien water and any potential
lifeforms that exist there. This doesn’t matter much on most of Mars as
everyone agrees that the vast majority is a sterile, frozen desert, but it
does matter for the recently discovered water. The Curiosity rover wasn’t
allowed to go anywhere near the apparently moist soil discovered near its
position. So the Model X components would have to be assembled from scratch
in a clean room, then packaged for shipment to Mars and final assembly
there. What’s that, you say? Humans would be doing the assembly and they
wouldn’t be sterile. Yup, that’s a tricky one. Right now there’s a Catch 22,
which has the essential element for life on Mars — water — being present,
but even figuring out how to test it scientifically is challenging, never
mind humans drinking it.
Okay, so we can’t just send a Tesla to Mars. What’s the good news?
Electric motors don’t need oxygen
This is actually why electric vehicles are kicking butt on the gnarliest
hill climb in the world, the Pikes Peak International Hill Climb. While
internal combustion motors start getting confused from lack of oxygen,
electric motors just keep sucking volts and climbing. That Mars is like a
mountain 3 times the height of Everest doesn’t matter to electric motors.
Internal combustion motors, on the other hand, do need oxygen.
Electricity is easy to find on Mars, gas not so much
So you are on Mars. It’s pretty easy to roll out your thin-film solar panels
and suck up some watts. Finding oil, refining it, and getting it to your
Not so much. And shipping thin-film solar to Mars is much easier than
shipping a tanker of gasoline.
Cool Mars wheels already exist
Want to to off-road on Mars? We’ve already done it and the wheels are
scalable. Mars Rover wheels can scale up and it’s been done. The sub-40%
gravity on Mars makes the cantilevered forces much more manageable. Big,
scalable, and with no pressurized bits.
Climate control is a feature, not a bug
Did you know you can go camping in luxury in a Tesla right now on Earth?
Climate control, glass roof, and no biting insects at the cost of 7% of
range per night. Translate that to Mars and maybe 20% of the daily sunlight
is converted into you and the batteries feeling comfortable.
Traction control is traction control
Unless Tesla has done something really stupid, traction control should work
just fine. And it will be absolutely necessary on Mars since fine dust is a
lot more like snow than sand. Without having seen any of the traction
control code or sensors on a Model X, a MEMS sensor that detects
differential axle rotational speeds and reduces power to one of them is a
basic feature. It’s much easier on electric vehicles than on internal
combustion vehicles because the torque and power curves are so much flatter,
so advantage Model X there. What’s most interesting to me is that in order
to get the 0–60 mph times Tesla currently manages, they likely have
sophisticated models of downforce for each vehicle at different speeds so
that they can maximize traction, but maybe they just do it from basics.
Obviously, downforce on Mars is 38% of Earth’s while mass and hence inertia
remain unchanged, so they might have to tweak the code for that.
So, you could retool a Tesla Model X and drive it around on Mars. But it
probably wouldn’t end up looking like a Model X. The rover that Mark Watney
drove around in the movie based on Andy Weir’s great book The Martian is
much more likely to be what the hacked vehicle would look like.
And if the original Tesla Roadster SpaceX is going to try to throw into Mars
orbit soon with the first test of its Falcon Heavy rocket — if that’s
actually real — actually makes it, it will likely stay in space and never be
brought down to Mars. It wouldn’t run, as it would just be a pile of metal
and brittle rubber.
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