Projects: MarsDials

The MarsDial
A closeup of one of the flight MarsDials shows the gnomon in the center; it will cast shadows on the face. Created: 2003. Credit: Cornell University / JPL / NASA

Design of the face of the MarsDial
The MarsDials on the Mars Exploration Rovers include "furniture" or decorations that are typical of many Earth sundials. A motto is traditional; the "Two Worlds, One Sun" motto was based on an idea from Louis Friedman. The face also contains the name of Mars written in 17 languages; mirrors (left and right sides) 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. Credit: Jim Bell, Bill Nye, Steve Squyres, Woody Sullivan, Jon Lomberg, Louis Friedman, and Tyler Nordgren

Messages on the sides of the MarsDial
The MarsDials on the Mars Exploration Rovers include "furniture" or decorations that are typical of many Earth sundials. Around all four sides of the plate were engraved a short text message and drawings, inspired by those of schoolchildren, that tell the tale of the mission. Credit: Jim Bell, Bill Nye, Steve Squyres, Woody Sullivan, Jon Lomberg, Louis Friedman, and Tyler Nordgren

Spirit's MarsDial: 11:01 AM, Local Solar Time
This image of the MarsDial was taken on 14 January 2004 at 07:44:47 Universal Time (Greenwich Mean Time). The Mars Exploration Rover Spirit was at a latitude of 15°26' S and a longitude of 178°33' W in the Gusev Crater; the Sun was at an azimuth of 76° (roughly east) and an elevation angle of 78°. The camera was looking towards azimuth 33° (roughly northeast). Student Astronaut Abby and Student Astronaut Shih-Han used image analysis software to determine that the center of the sphere's shadow corresponds to a time on Mars at the Gusev Crater site of 11:01 AM on sol number 11 of the mission. The shadow also indicates that at the site it is about halfway between the summer solstice and autumnal equinox (for the Southern Hemisphere). The southern summer solstice was on 29 September 2003 and the southern autumnal equinox will be on 5 March 2004. It is 107 sols past the summer solstice and 49 sols until the autumnal equinox. [Image:2P127338375IOF0224P2110L4C2.IMG] Credit: NASA/JPL/Cornell/The Planetary Society

MarsDial animation
This 17-frame movie shows the motion of the post's shadow across the face of Spirit's MarsDial from about 10 am to about 5 pm local solar time. The background flickers between the lander petal and the rocky surface of Mars because the images were captured both before and after Spirit stood up from the lander. The images were captured through a near-infrared filter on the left eye of the Pancam instrument. The red markings hour lines indicate the time of day (read from the center of the sphere's shadow). The curved lines marked "SS," EQ," and "WS" indicate the season. When these images were captured, it was late summer (midway between the summer solstice and autumnal equinox) at Spirit's southern hemisphere location. Hour lines were superimposed on the animations by Student Astronauts Wei Lin Tan and Vignan Pattamatta. Credit: NASA / JPL / Cornell / Wei Lin Tan / Vignan Pattamatta

MarsDial animation
This 7-frame movie shows the motion of the post's shadow across the face of Spirit's MarsDial from about 10 am to about 5 pm local solar time. The background flickers between the lander petal and the rocky surface of Mars because the images were captured both before and after Spirit stood up from the lander. To make each color frame, Spirit captured three images, one each through red, green, and blue filters on its left eye. The yellow markings hour lines indicate the time of day (read from the center of the sphere's shadow). The curved lines marked "SS," EQ," and "WS" indicate the season. When these images were captured, it was late summer (midway between the summer solstice and autumnal equinox) at Spirit's southern hemisphere location. Hour lines were superimposed on the animations by Student Astronauts Wei Lin Tan and Vignan Pattamatta. Credit: NASA / JPL / Cornell / Wei Lin Tan / Vignan Pattamatta

The Mars Exploration Rover mission's 50,000th image
The Mars Exploration Rover mission's 50,000th image was part of a sequence of images taken of the MarsDial through several different color filters. Here, the 50,000th, 50,001st, and 50,0002nd images are combined into a true-color image of the MarsDial, with Mars's reddish rocks and soil in the background. It appears dark becase it was relatively late in the day (4:31 p.m., local solar time) when the image was taken. Note that the center of the ring-shaped "sweep magnet," to the right of the MarsDial, is gray, not red; it is the only spot in the image not covered with red dust. Credit: NASA / JPL / Cornell

The 10,000th image of the MarsDial from Spirit
As of sol 701 of its mission, Spirit had acquired 10,000 separate images of its MarsDial. The 10,000th image was taken through a green filter (it is combined with two others to create this RGB composite). The MarsDial is pinkish with dust, but numerous "cleaning events" have whisked away most of the dust that has accumulated over the course of the mission. Credit: NASA / JPL / Cornell