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-------------------------- 2772 - MARS - several steps to Perseverance.
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- This Review covers the period 1975 to 2020. Several steps to the mission that is scheduled to launch next month, August 2020.
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- In 1975 NASA sent two pairs of orbiters and landers toward Mars. Viking 1 and Viking 2 both arrived at the Red Planet in 1976, and sent their lander to the surface while the orbiter remained working above.
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- The Viking program represented the first extended exploration of Mars, as each spacecraft lasted years and transmitted reams of information back to Earth.
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- Hopes of finding life on the Red Planet were dashed when the probes could not definitively prove the existence of microbes on the surface.
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- The Viking missions also revealed that the composition of Mars was almost identical to certain meteorites found on Earth. This suggested that some meteorites found on Earth were originally from Mars.
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- NASA's next attempt to reach the Red Planet came in the 1990s, when Mars Observer launched to the planet on Sept. 25, 1992. The spacecraft was lost just before it was supposed to achieve Mars orbit on Aug. 21, 1993.
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- While the loss of communication was never fully explained, the most likely cause was a fuel tank rupture that caused the spacecraft to spin and lose contact with Earth.
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- The loss was especially painful because the spacecraft had cost so much; an estimated $813 million, which was nearly four times the original budget for the project, according to NASA's Jet Propulsion Lab.
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- NASA's Mars Global Surveyor left Earth on Nov. 7, 1996, and arrived at Mars on Sept. 12, 1997. Its mission was extended several times until NASA lost contact with it in 2006.
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- MGS mapped the Red Planet from pole to pole, revealing many ancient signs of water, such as gullies and hematite (a mineral that forms in water). Data from MGS helped NASA decide where to land its future Mars rovers.
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- The Pathfinder lander and Sojourner rover arrived at Mars in July 1997. The lander was the first to use a set of airbags to cushion the landing, and Sojourner was the first rover to trundle around on Mars. Pathfinder was expected to last a month and Sojourner a week, but both remained in operation until September 1997, when contact was lost with Pathfinder.
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- The Mars Odyssey launched March 7, 2001 and arrived at the Red Planet on Oct. 24, 2001. The orbiter is still conducting its extended science mission. It broke the record for the longest-serving spacecraft at Mars on Dec. 15, 2010.
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- The spacecraft has returned about 350,000 images, mapped global distributions of several elements, and relayed more than 95 percent of all data from the Spirit and Opportunity rovers.
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- The two rovers, Spirit and Opportunity, were sent to the surface of Mars in 2004. Each discovered ample evidence that water once flowed on the Red Planet. Spirit died in a sand dune in March 2010, while Opportunity continued work for nearly another decade.
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- Opportunity fell silent during a sandstorm in summer 2018 and NASA declared the mission over in early 2019.
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- On Aug. 4, 2007, NASA launched a stationary lander called Mars Phoenix, which arrived at Mars on May 25, 2008, and found water ice beneath the surface. Phoenix's solar panels suffered severe damage from the harsh Martian winter, and communication with the $475 million lander was lost in November 2008.
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- After repeated attempts to re-establish contact, NASA declared Phoenix broken and dead in May 2010. The damage was confirmed in orbital photos taken at the Red Planet.
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- The more powerful rover, called Curiosity, arrived at Gale Crater in 2012 to search for signs of ancient habitable environments. Its major findings include finding previously water-soaked areas, detecting methane on the surface and finding organic compounds. -
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- Opportunity's design has inspired another rover, temporarily called Mars 2020, which will continue with more advanced investigations when it arrives on the Red Planet.
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- Mars InSight was launched to the Red Planet in 2018, and the spacecraft safely landed that November. As of early 2019, the lander is setting up its instruments to examine the interior of Mars.
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- The Mars Perseverance rover mission is part of NASA's Mars Exploration Program, a long-term effort of robotic exploration of the Red Planet. The Mars Perseverance mission addresses high-priority science goals for Mars exploration, including key questions about the potential for life on Mars.
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- The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. The Mars Perseverance rover introduces a drill that can collect core samples of the most promising rocks and soils and set them aside in a "cache" on the surface of Mars.
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- The mission also provides opportunities to gather knowledge and demonstrate technologies that address the challenges of future human expeditions to Mars. These include testing a method for producing oxygen from the Martian atmosphere, identifying other resources (such as subsurface water), improving landing techniques, and characterizing weather, dust, and other potential environmental conditions that could affect future astronauts living and working on Mars.
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- The mission is timed for a launch opportunity in August 2020 when Earth and Mars are in good positions relative to each other for landing on Mars. That is, it takes less power to travel to Mars at this time, compared to other times when Earth and Mars are in different positions in their orbits.
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- To keep mission costs and risks as low as possible, the Mars 2020 design is based on NASA's successful Mars Science Laboratory mission architecture, including its Curiosity rover and proven landing system.
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- July 12, 2020 2772
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--------------------- Sunday, July 12, 2020 -------------------------
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