Mars Odyssey
NASA’s robotic spacecraft orbiting the planet Mars launched on April 7, 2001 on a Delta II rocket from Cape Canaveral Air Force Station, and reached Mars orbit on October 24, 2001.
Mission is to use spectrometers and electronic imagers to detect 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 Exploration Rovers, Mars Science Laboratory, and the Phoenix lander to Earth.
It currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth.
Mars Express
A space exploration mission launched in 2003 by the European Space Agency (ESA). The Mars Express mission is exploring the planet Mars, and is the first planetary mission attempted by the agency.
Mars Express consists of two parts, the Mars Express Orbiter and the Beagle 2, a lander designed to perform exobiology and geochemistry research. Although the lander failed to land safely on the Martian surface, the orbiter has been successfully performing scientific measurements since early 2004.
Opportunity (Rover)
Opportunity (launched by NASA), also known as MER-B (Mars Exploration Rover – B) or MER-1, is a robotic rover active on the planet Mars since 2004 .
On July 28, 2014, NASA announced that Opportunity, after having travelled over 40 km on the planet Mars, has set a new “off-world” record as the rover having driven the greatest distance, surpassing the previous record held by the Soviet Union’s Lunokhod 2 rover that had travelled 39 km on the Moon.
Mission highlights include the initial 90 sol mission, finding extramartian meteorites such as Heat Shield Rock (Meridiani Planum meteorite), and over two years studying Victoria crater. It survived dust-storms and reached Endeavour crater in 2011, which has been described as a “second landing site”.