Por:
William J. Palm
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Fecha:
2019
NASAs planetary rover Sojourner landed on Mars on July 4, 1997, and excited people on Earth while they watched it successfully explore the Martian surface to determine wheelsoil interactions, to analyze rocks and soil, and to return images of the lander for damage assessment. Then in early 2004, two improved rovers, Spirit and Opportunity, landed on opposite sides of the planet. In one of the major discoveries of the 21st century, they obtained strong evidence that water once existed on Mars in significant amounts. Although planned to operate for only 90 Martian days, Spirit operated for over five years, became stuck in 2009, and stopped communicating in 2010. The rover likely lost power due to excessively cold internal temperatures. Opportunity was still active as of 2016, having already exceeded its planned operational life by over twelve Earth years, almost 50 times its designed lifespan. The rover Curiosity landed on Mars in 2012 less than 2.4 km (1.5 mi) from its intended target after a 563,000,000 km (350,000,000 mi) journey. It was designed to investigate the Martian climate and geology; to assess whether the Gale crater ever had an environment suitable for microbial life, and to determine the habitability of the site for future human exploration. Curiosity has a mass of 899 kg (1,982 lb) including 80 kg (180 lb) of instruments. The rover is 2.9 m (9.5 ft) long by 2.7 m (8.9 ft) wide by 2.2 m (7.2 ft) in height.