Mars Polar Lander Mars Descent Imager (MARDI) History and Background

The Mars Descent Imager (MARDI) onboard the Mars Polar Lander is not the first camera to be used during descent toward the surface of another world--but it is the first for the planet Mars. Previous descent imagers were included on the U.S. Ranger, Surveyor, and Apollo lander missions to Earth's Moon in the 1960s and early 1970s. A second MARDI, provided by Malin Space Science Systems for the Mars Surveyor 2001 lander, is expected to reach the red planet in January 2002. A descent imager has also been included on the Huygens probe, scheduled to land on Saturn's moon Titan in December 2004.

Here are some brief discussions of some missions to other worlds, highlighting those that carried descent imaging systems:


The Ranger missions to the Moon took place in the years 1961-1965. The Rangers were the "ultimate" in descent camera systems--their entire mission was to take pictures as the spacecraft fell toward the lunar surface. No attempt was made to safely land the Rangers---they simply crashed into the Moon at full flight velocity.


In the 1990s and 2000s, we have come to think of "Surveyor" as being a Mars exploration program. However, during the 1960s there was another "Surveyor" program that was designed to determine whether the U.S. could safely land a spacecraft on the surface of the Moon. The Lunar Surveyor program was conducted between 1966 and 1968. The first two landers, Surveyor 1 and Surveyor 2, carried descent imagers, but the descent images were not returned.


Six Apollo missions each landed 2 people on the Moon between 1969 and 1972. Each lander, known as the "Lunar Module," took pictures during the descent toward the lunar surface. These pictures, especially those from the first landing (Apollo 11), are among some of the most dramatic pictures shot in the 20th Century.

Viking and Mars Pathfinder

All three U.S. landers sent to Mars prior to the present Mars Polar Lander mission were great successes. The Viking 1 and 2 landers touched down in July and September 1976 (respectively), and Mars Pathfinder arrived in July 1997. None of these spacecraft had a descent imaging system.

Mars Polar Lander

The Mars Polar Lander was launched January 3, 1999, and scheduled to touch down on December 3, 1999, in the south polar region of Mars. The Mars Decent Imager (MARDI) will acquire all of its data during the moments leading up to the touchdown, from the time that the spacecraft's heat shield falls away until the spacecraft reaches the surface.

Mars Surveyor 2001 Lander

The Mars Surveyor 2001 lander will be launched in April 2001 and is scheduled to land on Mars in January 2002. A Mars Descent Imager (MARDI) exactly like the one flown on the Mars Polar Lander has been purchased by NASA/JPL from Malin Space Science Systems (MSSS). Through a separate contract, MSSS President Michael Malin was selected in 1997 to be the Descent Imager Science Team Leader.


Huygens is a probe scheduled to land on Saturn's moon, Titan, in December 2004. It is being carried by the Cassini spacecraft, which was launched in October 1997. Huygens was built by the European Space Agency and it carries a descent imaging system that will show what the surface looks like beneath Titan's thick cloud-covered skies.

©1999 Malin Space Science Systems, Inc.