By Jon Lomberg

Jon Lomberg imagines a future where humans have colonised Mars.

A few centuries from now, Mars might be a bustling frontier. If our species can survive there, it will spread slowly, pushed by the spirit of scientific inquiry, or the urge to explore. Landing sites will turn into bases and eventually into communities.

Mars has as much dry surface area as the Earth. Even aided by satellites, it will take a very long time to explore the planet. Meanwhile, all the unmanned landers and rovers from earlier missions will still be where they were centuries before, buried in sand perhaps.

Eventually some prospector, geologist or homesteader will find these ancient relics, the precursors to human presence on Mars. When this happens, these historical objects may have the same emotional resonance as a spar or cannon from James Cook’s ship Endeavour would have for someone in Australia.

(Or perhaps the discovery of Aboriginal Australian rock art? – ed)

Two of the dead spacecraft discovered will be the NASA rovers Spirit and Opportunity. These two small robots improbably landed on Mars nested inside a sphere of balloon airbags that bounced along the rocky surface until coming to a halt and deflating. The rovers emerged to begin a trip intended to last 90 days. The journey for the Spirit and Opportunity rovers, however, extended past five years.

One of the objects on the outer surface of each rover is a color calibration target, used by the camera teams to verify the colors the camera saw. Camera Team leader Steve Squyres of Cornell University got the idea to turn this target into an educational opportunity for the children of Earth, and proposed a sundial for use by science teachers.

Sundials are among the most ancient of scientific instruments. All you need is a vertical post (the gnomon) casting a shadow onto a flat surface. With that you can tell many things: the time of day, the season, even the latitude of the sundial. As such, sundials are excellent objects for school science lessons.

With respect to sundials, Mars is a great location. The Martian day is only a little longer than Earth’s, and the year is almost exactly twice as long as Earth’s. The tilt of the planet’s axis is also similar to Earth’s. This means the principles that guide sundials here will work just as well on Mars – with the exception that the sundials are on a moving platform. Sundials are traditionally stationary! This motion introduces another element in the equation: the positioning of the sundial relative to Mars north was constantly changing, so the sundial, once understood, is also a compass.

Squyres assembled a team of Mars scientists and educators to construct two ‘MarsDials’ to be carried on the two Mars rovers. I served as the artist who sketched out designs that also met the NASA requirements for this color calibration patch.

The design shows the orbits of Mars and Earth with the planets at the position they were at the time of launch. Small arcs of the dials (shown pale orange in the picture) have a mirror-surface that would provide a steady stream of information about the color of the Martian sky overhead – a direction the cameras never pointed. Not one square millimeter of the available MarsDial space is wasted.

Louis Friedman of The Planetary Society suggested the motto ‘Two Worlds, One Sun’. My contribution was to suggest decorating the dial with the names Mars was given by different cultures on Earth.

Researching these names was a difficult task, since we wanted the broadest range of cultures—including the ancient Sumerian cuneiform and Mayan glyphs that represented Mars.

As with all Mars-bound objects, the 3-inch square dials needed to resist the stresses of vibration and acceleration at launch.During interplanetary cruise they had to survive weightlessness, and alternately roasting and freezing under Sun and shadow. Each dial is metal and a kind of rubbery plastic, glued together in the colors and shapes the design required. Originally the ball at the top of the gnomon was to be golden. Testing showed that it scattered too much glare toward the camera, so it was repainted a more sober black.

Since it is the calibration target, images of the MarsDial are frequently sent back to Earth. As the rovers have roamed the surface, the sundial has been seen against many different Martian landscapes.

The base of the dials is a 3-inch square. Each edge is about ¼-inch high. These vertical edges afforded some more priceless disk ‘real estate’, so I suggested this surface might be used for another function the MarsDial could perform: communicate to the future. When future people discover the rover on Mars, the decorated sundial might seem rather odd. Why is it there?

The sides of the dial feature a greeting to these future human/Martians, explaining what the MarsDial is and why we sent it. Since it was intended to teach the children of Earth about Mars, the message was illustrated with stick figures drawn by children, which I incorporated into the little vignettes bordering the text.

The final version of the message was penned by Bill Nye, the Science Guy.

When you see the dial itself, the engraving seems rather tiny. But it’s not unreasonable to suppose that people whose technology lets them live on Mars will have magnifying glasses!

The humble MarsDial may someday find a home in the library of the University of Mars, relics of a time when the human presence on Mars was just a dream.

www.jonlomberg.com
www.galaxygarden.net

Tags: Art, astronomy, Mars

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