Mars Exploration
Apart from the Earth, Mars is the most visited and studied planet, with a total of 11 missions dedicated to learning more about out nearest neighbour. Orbiters, Landers and Rovers have been sent to Mars to study the planet's surface, climate, and geography. There have also been a few fly-by spacecraft.
Apart from the Earth, Mars is the most visited and studied planet, with a total of 11 missions dedicated to learning more about out nearest neighbour.
Orbiters, Landers and Rovers have been sent to Mars by the Soviet Union, the United States, Europe, and Japan to study the planet's surface, climate, and geography. There have also been a few fly-by spacecraft who stopped off to take pictures on their way further out into the solar system.
Roughly two-thirds of all spacecraft destined for Mars have failed in one manner or another before completing or even beginning their missions. Part of this high failure rate can be ascribed to technical problems, but enough have either failed or lost communications for no apparent reason that some researchers speak of a mysterious Earth-Mars "Bermuda Triangle"
1965 - Mariner 4
Mariner 4 Orbiter
Photo Credit: NASA.
The first successful fly-by mission to Mars was NASA's Mariner 4 launched on November 28, 1964 on a 228-day mission to Mars. The spacecraft passed Mars at a distance of 9,868 kilometres (6,118 miles), recording and transmitting to Earth the first close-up picture of the red planet. In 22 pictures, Mariner's TV camera scanned about one percent of the Martian surface, revealing ancient craters of varying size. These 22 images are mankind's first images taken by a planetary spacecraft and have great historical value.
1971 - Mars Probe Program
The first objects to land on the surface were two Soviet probes from the Mars Probe Program, launched in 1971, but both lost contact within seconds of landing.
1975 - Viking Program
Viking image of the Martian surface.
Photo Credit: NASA
Then came the 1975 NASA launches of the Viking program, which consisted of two Orbiters, each having a Lander. Both Landers successfully touched down in 1976. It was the most expensive and ambitious mission ever sent to Mars. It was highly successful and formed most of the database of information about Mars until the late 1990's and early 2000's.
The Viking landers conducted biological experiments designed to detect life in the Martian soil if it existed. The results were initially positive and met some of NASA's criteria for the detection of life. But, on further analysis most scientists became convinced that the results were likely caused by a non biological chemical reaction. However, the matter is still under debate.
The craft eventually failed, one by one, and after 6 years of operation the Viking program was finally shut down in 1983.
1992 - Mars Observer
Mars Observer Orbiter (artist impression).
Photo Credit: NASA
After a 17-year gap since the last mission to the red planet, NASA launched the Mars Observer on September 25, 1992. The spacecraft was based on a commercial Earth-orbiting communications satellite that had been converted into an orbiter for Mars. The payload of science instruments was designed to study the geology, geophysics and climate of Mars.
The mission ended with disappointment on August 22, 1993, when contact was lost with the spacecraft shortly before it was to enter orbit around Mars.
1996 - Mars Global Surveyor
Mars Global Surveyor (artist impression)
Photo Credit: NASA
Following the 1992 failure of NASA's Mars Observer orbiter, they launched the Mars Global Surveyor in 1996.
The spacecraft circles Mars once every 117.65 minutes at an average altitude of 378 kilometres (235 miles). It is in a polar orbit which is almost perfectly circular, moving from being over the south pole to being over the north pole in just under an hour. The altitude is chosen to make the orbit sun-synchronous, so that all images taken by the spacecraft of the same surface features on different dates are taken under identical lighting conditions. After each orbit, the spacecraft views the planet 28.62? to the west because Mars has rotated underneath it. In effect, it is always 14:00 for Mars Global Surveyor as it moves from one time zone to the next exactly as fast as the Sun. This ensures eventual full coverage of the entire surface. The Mars Global Surveyor Mission was a complete success, and completed its primary mapping mission in early 2001. It is now on and extended mission and it acts as a relay for some of the other missions.
1996 - Mars Pathfinder
Mars Pathfinder Rover.
Photo Credit: NASA
Only a month after the launch of the Surveyor, NASA launched the Mars Pathfinder, carrying a robotic exploration vehicle, which landed in the Ares Vallis on Mars.
The mission carried a series of different scientific instruments to analyse the Martian atmosphere, climate, geology and the composition of its rocks and soil.
This mission was another big success, and received much publicity, partially due to the many spectacular images that were sent back to Earth. The mission was programmed to last a week to a month, it eventually lasted for almost 3 months. The final contact with the Pathfinder was on September 27, 1997. Although the mission planners tried to restore contact during the following five months, the successful mission was terminated on March 10, 1998.
Though completely successful and completing real objectives, the Mars Pathfinder mission can be regarded as a "proof-of-concept" for various technologies, such as airbag-mediated touchdown and automated obstacle avoidance, both later exploited by the Mars Exploration Rovers. The Mars Pathfinder was also remarkable for its extremely low price relative to other unmanned space missions. This was an important achievement, considering that approximately two-thirds of the spacecraft destined for Mars have either failed to launch or were lost en route.
Pathfinder Panorama
Photo Credit: NASA
2001 - Mars Odyssey
Mars Odyssey.
Photo Credit: NASA
In 2001 NASA launched the successful Mars Odyssey orbiter, which is still in orbit as of March 2006. Its mission is to use spectrometers and imagers to hunt for evidence of past or present water and volcanic activity on Mars. It is hoped that the data Odyssey obtains will help answer the question of whether life has ever existed on Mars. It also acts as a relay for communications between the Mars Explorations Rovers and Earth.
NASA has approved an extended mission through September 2006 to allow observation of year-to-year differences in phenomena like polar ice, clouds and dust storms. The extension will also continue Odyssey's support for other Mars missions. About 85 percent of images and other data from NASA's twin Mars rovers, Spirit and Opportunity, have reached Earth via communications relay by Odyssey, which receives transmissions from both rovers every day. The orbiter helped analyse potential landing sites for the rovers and is doing the same for NASA's Phoenix mission, scheduled to land on Mars in 2008.
2003 - Mars Express
Mars Odyssey
Photo Credit: NASA
In 2003, the ESA launched the Mars Express craft consisting of the Mars Express Orbiter and the lander Beagle 2. Beagle 2 apparently failed during descent and was declared lost in early February 2004. Beagle 2 was conceived by a group of British academics headed by Professor Colin Pillinger of the Open University, in collaboration with the University of Leicester. Its purpose was to search for signs of Martian life, past or present, and its name reflected this goal. HMS Beagle was the ship that took Darwin on his voyage around the world in the 1830s and led to our knowledge about life on Earth. In early 2004 the Planetary Fourier Spectrometer team announced it had detected methane in the Martian atmosphere.
2003 - Mars Exploration
Mars rover 'Spirit'
Photo Credit: NASA
Also in 2003, NASA launched the twin Mars Exploration Rovers named Spirit (MER-A) and Opportunity (MER-B). Both missions landed successfully in January 2004 and have met or exceeded all their targets. Among the most significant science returns has been the conclusive evidence that liquid water existed at some time in the past at both landing sites.
Both rovers have completed their second year of science operations on the surface of the Red Planet and are rolling on into a third year. The robots were only designed to have an operational lifespan of only three months. It was expected that dust in the atmosphere would settle on the solar panels, making them less effective until the point where the rovers have no power source. To everybody's surprise, Martian dust devils are passing over the Rovers at over 100mph and are cleaning their solar panels, and thus extending their lifespan.
2005 - Mars Reconnaissance
The Mars Reconnaissance Orbiter.
Photo Credit: NASA
On August 12, 2005 the NASA Mars Reconnaissance Orbiter probe was launched toward the planet, to conduct a two-year science survey. The purpose of the mission is to do more studies and prepare the upcoming lander missions. It arrived in orbit on March 10, 2006.
Mars Reconnaissance Orbiter features a high resolution camera, HiRISE (High Resolution Imaging Science Experiment), which is able to resolve objects downto 7.5 metres across. It has also revealed evidence of that liquid water was once present.
The next scheduled mission to Mars is the NASA Phoenix Mars lander, expected to launch in 2007.
References
- NASA copyright policy states that "NASA material is not protected by copyright unless noted".
- JPL Mars Exploration Program
- The Nine Planets
- Wikipedia
