Context:

• NASA has announced the end of the Opportunity rover’s mission. Opportunity rolled out on to the Martian surface in 2004, 20 days after its twin, Spirit, had landed on the other side of the Red Planet.
• Over the next 14 years, it got successes that made it one of the most overachieving explorer robots ever built.

Spirit and Opportunity Rovers

• Spirit and Opportunity were identical, golf-cart-sized, solar-powered rovers. Spirit landed at Gusev Crater; Opportunity followed, landing on the opposite side of Mars at Meridiani Planum.
• Contact with Spirit was lost in March 2010, and the mission was declared over in May, 2011.
• Opportunity worked on Mars for over 14 years, longer than any other robot. Both rovers were originally supposed to have only 90-day missions.
• Opportunity travelled 45.16 km on the surface of Mars, more than any other rover.
• Its equipment have been compromised by the storm, which struck while the rover was at a site called Perseverance Valley.

Presence of Water

• Haematite-rich small spherules, concretions nicknamed “blueberries” as photographed by Opportunity provided evidence of a watery ancient environment.
• Foremost among Spirit and Opportunity’s many science discoveries: Mars was likely wetter and warmer in the past.
• These conditions could have served as a cradle for life on Mars at a time when life first emerged on Earth.
• Opportunity was the first rover to identify and characterize sedimentary rocks on a planet other than Earth.
• Opportunity found white veins of gypsum, a sign of water that travelled through underground fractures. It also discovered clay minerals that formed in neutral-pH water.

Significance of the mission

• For over 14 years, Opportunity encountered challenges that called for skill and innovation to overcome.
• It drove in reverse, negotiated loose surfaces, sand traps, and slopes as steep as 31 degrees.
• The rover demonstrated reliable Mars-Earth communication. Curiosity and the upcoming Mars 2020 rovers is build upon their lessons.