PASADENA, CA: Do you know the local time on Mars? Ask one of The Planetary Society’s Student Astronauts. An image of a Mars-based sundial, called a MarsDial, has been processed by these teenaged members of the Mars Exploration Rover team and has just been released by NASA. It and future MarsDial images are available at and at

The Student Astronauts are part of The Planetary Society/LEGO Red Rover Goes to Mars Project, the first educational experiment selected by NASA for a planetary mission.

The MarsDial resulted from a brainstorm of Bill Nye the Science Guy, a Planetary Society board member.

“I thought nothing could be more cool to show that Mars is a real world orbiting the Sun, just like the Earth, than to have a sundial marking the passage of time there,” said Nye.

Nye worked with Steve Squyres, the principal investigator for the rover missions, and a team of five others to develop the MarsDial for flight. Technically, it is the image calibration fixture for the rover cameras, used like a television test pattern. The other team members were Louis Friedman, Executive Director of The Planetary Society; James Bell, lead researcher for the high-resolution stereo panoramic cameras carried by both rovers; Woodruff “Woody” Sullivan, University of Washington, an astronomer and sundial expert; Tyler Nordgren, University of Redlands in California; and Jon Lomberg, artist and creative consultant to the Mauna Kea Center for Astronomy Education, University of Hawaii at Hilo.

“We will have people as young as 13 on The Planetary Society’s Student Astronaut team working with scientists at the Jet Propulsion Laboratory to process the images,” said Nye.

The Student Astronauts – 16 young people from 12 different countries – will work at JPL in teams of two, each pair remaining one week. They will process new MarsDial images every one to two days through the end of February, 2004. The students were selected by The Planetary Society in the Red Rover Goes to Mars education activity. Red Rover Goes to Mars is privately funded by The Planetary Society and the LEGO Company.

Bruce Murray, Chairman of the Board of The Planetary Society and a planetary scientist added, “These student astronauts involved with the mission, bring closer the day for true public participation in planetary exploration. They will inspire a new generation of Mars explorers.”

Nye noticed that a calibration fixture for the Pancam (Panoramic camera) aboard NASA’s 2001 Mars Surveyor Lander looked like a sundial. Although that mission was cancelled, the sundial/calibration target was later incorporated into the instruments on board the twin rovers of NASA’s Mars Exploration Rover mission. Color and intensity calibrations are necessary to adjust the cameras so scientists receive true-color images of the Martian terrain explored by the rovers.

Each rover, Spirit and Opportunity, carries an identical MarsDial, approximately three inches square. Louis Friedman coined the sundial’s motto: Two Worlds, One Sun.

While ordinary sundials are fixed in place, the MarsDials will be continually moving with the rovers. So, the MarsDials have no hour lines because the rovers’ changing positions would render such markings useless. Instead, the Student Astronauts on the science team add hour marks electronically to the images, using software developed at Cornell in collaboration with Woody Sullivan at the University of Washington. The MarsDial’s shadow also indicates the date during the Martian year.

The Jet Propulsion Laboratory in Pasadena, a division of the California Institute of Technology, manages NASA’s Mars Exploration Rover project; Cornell University in Ithaca, N.Y., manages the science instruments carried by the two rovers.



Carl Sagan, Bruce Murray and Louis Friedman founded The Planetary Society in 1980 to advance the exploration of the solar system and to continue the search for extraterrestrial life. With members in over 125 countries, the Society is the largest space interest group in the world.


Susan Lendroth
The Planetary Society
Phone: (626) 793-5100 ext. 237

Warren Betts
Warren Betts Communications
Phone: (626) 836-2080 Fax: (626) 836-3040