Title: Rover (space exploration)
Content:  The Mars Pathfinder mission included Sojourner, the first rover to successfully deploy on another planet. NASA, the space agency of the United States, launched Mars Pathfinder on 4 December 1996; it landed on Mars in a region called Chryse Planitia on 4 July 1997. From its landing until the final data transmission on 27 September 1997, Mars Pathfinder returned 16,500 images from the lander and 550 images from Sojourner, as well as data from more than 15 chemical analyses of rocks and soil and extensive data on winds and other weather factors.
Title: Mars
Content:  similar to 5261 Eureka, a Mars trojan. Mars has been explored by several uncrewed spacecraft. Mariner 4 was the first spacecraft to visit Mars; launched by NASA on 28 November 1964, it made its closest approach to the planet on 15 July 1965. Mariner 4 detected the weak Martian radiation belt, measured at about 0.1% that of Earth, and captured the first images of another planet from deep space. The latest spacecraft to successfully land on Mars are CNSA's Tianwen-1 lander and Zhurong rover, landed on 14 May 2021. Zhurong rover was successfully deployed on 22 May 2021, which makes China the 
Title: Rover (space exploration)
Content:  On 26 November 2011, NASA's Mars Science Laboratory mission was successfully launched for Mars. The mission successfully landed the robotic Curiosity rover on the surface of Mars in August 2012. The rover is currently helping to determine whether Mars could ever have supported life, and search for evidence of past or present life on Mars.
Title: Mars Pathfinder
Content:  Mars Pathfinder (MESUR Pathfinder) is an American robotic spacecraft that landed a base station with a roving probe on Mars in 1997. It consisted of a lander, renamed the Carl Sagan Memorial Station, and a lightweight, 10.6 kg wheeled robotic Mars rover named Sojourner, which became the first rover to operate outside the Earth–Moon system. Launched on December 4, 1996 by NASA aboard a Delta II booster a month after the Mars Global Surveyor was launched, it landed on July 4, 1997 on Mars's Ares Vallis, in a region called Chryse Planitia in the Oxia Palus quadrangle. The lander then opened, exposing the rover which conducted many experiments 
Title: Exploration of Mars
Content:   Mars Pathfinder was a U.S. spacecraft that landed a base station with a roving probe on Mars on July 4, 1997. It consisted of a lander and a small 10.6 kg wheeled robotic rover named Sojourner, which was the first rover to operate on the surface of Mars. In addition to scientific objectives, the Mars Pathfinder mission was also a "proof-of-concept" for various technologies, such as an airbag landing system and automated obstacle avoidance, both later exploited by the Mars Exploration Rovers.
Title: Mars rover
Content: 🇺🇸 Curiosity of the Mars Science Laboratory (MSL) mission by NASA, was launched November 26, 2011 and landed at the Aeolis Palus plain near Aeolis Mons (informally "Mount Sharp")   in Gale Crater on August 6, 2012.   The Curiosity rover is still operational as of June 2021. 🇺🇸 Perseverance, NASA rover based on the successful Curiosity design. Launched with the Mars 2020 mission on July 30, 2020, it landed on February 18, 2021. It carried the Mars Helicopter Ingenuity attached to its belly. 🇨🇳 Zhurong launched with the Tianwen-1 CNSA Mars mission on July 23, 2020, landed on May 14, 2021 in the southern region of Utopia Planitia, and deployed on May 22, 2021, while dropping a remote selfie camera on 1 June, 2021.   
Title: Zhurong (rover)
Content:  Zhurong is a Mars rover that is China's first rover to land on another planet (they had previously landed two rovers on the Moon). It is part of the Tianwen-1 mission to Mars conducted by the China National Space Administration (CNSA). The spacecraft was launched on 23 July 2020 and inserted into Martian orbit on 10 February 2021. The lander, carrying the rover, performed a successful soft-landing on Mars on 14 May 2021, making China the second country to successfully soft-land a spacecraft on Mars and establish communications from the surface, after the United States. Zhurong was successfully deployed on 22 May 2021, 02:40 UTC.
Title: Exploration of Mars
Content:  rover (MER-A) was active until 2010, when it stopped sending data because it got stuck in a sand dune and was unable to reorient itself to recharge its batteries. On 10 March 2006, NASA's Mars Reconnaissance Orbiter (MRO) probe arrived in orbit to conduct a two-year science survey. The orbiter began mapping the Martian terrain and weather to find suitable landing sites for upcoming lander missions. The MRO captured the first image of a series of active avalanches near the planet's north pole in 2008. Rosetta came within 250 km of Mars during its 2007 flyby. Dawn flew by Mars in February 2009 
Title: Mars rover
Content:   A Mars rover is a motor vehicle designed to travel on the surface of Mars. Rovers have several advantages over stationary landers: they examine more territory, they can be directed to interesting features, they can place themselves in sunny positions to weather winter months, and they can advance the knowledge of how to perform very remote robotic vehicle control. They serve a different purpose than orbital spacecraft like Mars Reconnaissance Orbiter. A more recent development is the Mars helicopter. , there have been six successful robotically operated Mars rovers; the first five, managed by the American NASA Jet Propulsion Laboratory, were (by date of Mars landing): Sojourner (1997–1997), Opportunity (2004–2018), Spirit (2004–2010), Curiosity (2012–), and Perseverance (2021–). The sixth, managed by the China National Space Administration, is Zhurong (2021–). On January 24, 2016, NASA reported that then current studies on Mars by 
Title: Zhurong (rover)
Content:  operate a fully functional spacecraft on Martian surface, after the United States. After establishing stable communication with the rover, CNSA released its first pictures from the surface of Mars on 19 May 2021. On 22 May 2021, at 10:10 a.m. Beijing time (0240 GMT), Zhurong drove from its landing platform to the surface of Mars, starting its exploration mission. On 11 June 2021, CNSA released the first batch of scientific images from the surface of Mars including a panoramic image taken by Zhurong, and a colored group photo of Zhurong and the Tianwen-1 lander taken by a wireless camera placed on Martian soil. The panoramic image is composed of 24 single shots taken by the NaTeCam before the rover was deployed to the 

Question: when did we first put a rover on mars?
Answer: January 2004.