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Projects: MarsDialsHistoryThe history of the MarsDial project begins with Ned Nye, the father of Bill Nye, The Planetary Society’s Vice President. Ned Nye became fascinated by sundials after he was captured by the Japanese Navy from Wake Island during World War II. During the nearly four years that Ned Nye was a prisoner, he was moved repeatedly to different locations. Bill Nye recalls, “he told us that he used to try to determine their latitude using the shadows of fence posts, shovel handles, and the like. He became interested in sundials. Hey, who wouldn’t?” After his release and return home, Ned Nye took pictures of sundials throughout the eastern United States, and wrote a book, Sundials of Maryland and Virginia. His father’s love of sundials rubbed off on young Bill. Fast forward to 1998, when a new mission to Mars was taking shape. Called Mars Surveyor 2001, it would carry a group of instruments to the Martian surface that were collectively called the Athena science payload. One of the instruments in the Athena payload was the Panoramic Camera, or Pancam, a high-resolution color camera system being developed by Cornell astronomy professor Jim Bell. Bell was on an airplane when he noticed Nye -- by then a well-known TV personality -- sitting nearby. Bell struck up a conversation with Nye about Mars missions and Pancam in particular. Bell explained that in order to measure the photometric properties of the materials on Mars -- that is, how the Mars rocks and dust reflected light of different wavelengths and from different directions -- the Athena payload would also include a calibration target. The calibration target would consist of a vertical post, about 10 centimeters (4 inches) long, that would cast a shadow across rings of gray color. The photometric properties of the gray rings would be very well known. Each time the Pancam took a set of images of a Mars target, it would also take a picture of the calibration target for comparison. Why the vertical post? On Earth, a shadow cast onto a white piece of paper looks mostly gray, but also a little bit blue. That blue color comes from the scattering of sunlight as it passes through the molecules in our sky. On Mars, whose sky is somewhere between salmon pink and tan in color, shadows have a very faintly red or brown color. Study of the color of the shadow cast by the vertical post would thus reveal information about the color of the sky, and its influence on the color of objects visible to Pancam. When Nye learned about Pancam and its stick-casting-a-shadow calibration target, he had an epiphany: “It’s a sundial!” Bill’s eyes lit up as he foresaw an opportunity to merge science, education, his own personal interest in sundials, and space exploration into an exciting new project. That mundane little object could become the first sundial on another planet! Wouldn’t it be great if we could tell time on Mars by reading the post’s shadow? Bell invited Nye to an Athena team meeting, where they presented the idea. Other Athena team members were initially skeptical (“Uh, Bill, this is the space program. We have a lot of very good clocks.”), but within a few weeks Steve Squyres, the Principal Investigator for the Athena payload, had embraced the idea, and the MarsDial was born. Once the decision was made by the Pancam team to make a MarsDial, an informal design team was assembled that met via e-mail over a period of more than 6 months. On the team, in addition to Bell, Nye, and Squyres, were Woody Sullivan, a professor of astronomy at the University of Washington and self-proclaimed sundial fanatic; Jon Lomberg, a well-known artist specializing in astronomical subjects; Louis Friedman, Executive Director of The Planetary Society; and Tyler Nordgren, an astronomer and artist then at the U.S. Naval Observatory and now at the University of Redlands. Dan Britt, a planetary geologist now at the University of Central Florida who designed the calibration target for the Pathfinder mission to Mars, supplied the specially pigmented silicone rubber. Larry Stark, scientific instrument maker at the University of Washington, was the key person for turning the design ideas into reality. In the process of the development of the MarsDial, it was made into a piece of interplanetary art. For example, a motto is traditional on sundials. At one point, Friedman suggested “One Sun - Two Worlds.” After much discussion, “Two Worlds, One Sun” was adopted as the motto by the MarsDial team. Other “furniture,” as sundial decoration is called, included the name of Mars written in 17 languages; mirrors to reflect the color of the Martian sky; blue and red dots representing Mars and Earth, sitting on gray ovals of the same shape and relative size as the planets’ orbits. Finally, around all four sides of the plate were engraved a short text message and drawings, again inspired by those of schoolchildren, that tell the tale of the mission. How many years will it be before a human comes upon a half-buried rover, dusts it off, and first reads these words on Mars? One piece of decoration conspicuously lacking on the MarsDials was the hour markings that are used to identify the time of day from the position of the shadow. The hour markings could not be added before landing because when the spacecraft landed on Mars, its compass orientation would be completely random. Bell, Sullivan, and Nye discussed the idea of adding hour markings to images of the MarsDial through the use of computer software. The software would read engineering information about the orientation of the lander and use that to draw the hour markings on each MarsDial image. In 1999, disaster struck; two spacecraft, Mars Polar Lander and Mars Climate Orbiter, vanished upon arrival at Mars. Investigations revealed that errors had been made that had doomed the two missions, and NASA elected to postpone, and eventually cancel, the Mars Surveyor 2001 lander. But the Athena science payload survived the cancellation intact, and it was later incorporated into the science instrument payload for the Mars Exploration Rovers, launched in 2003. As the first Mars Exploration Rover, Spirit, approached the Red Planet, the Athena science team madly prepared for the arrival. At the same time, The Planetary Society’s Red Rover Goes to Mars Student Astronauts prepared to join the Athena science team inside mission operations at JPL for the first critical months of the mission. Bell offered the Student Astronauts a role on the Pancam team: they could be the ones to process the MarsDial images, imposing the hour markings, producing animations and movies. The Student Astronauts witnessed live the thrilling landings and first weeks of operation of both Spirit and Opportunity. In addition to watching the scientists work and participating in discussions of the new discoveries made each sol by the rovers, they methodically processed the MarsDial images. Two of the Student Astronauts, Courtney Dressing and Rafael Morozowski, unveiled the first hour-lined images of the MarsDial at a press conference at JPL on January 9, 2004. The MarsDials also inspired an imitation on Earth, the EarthDial Project. [LINK TO EARTHDIAL PAGE] |
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