After nearly 15 years, NASA's Opportunity Mars rover mission has come to an end. On Tuesday, the Space Flight Operations Facility at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California transmitted the final rescue command signals via the Goldstone Deep Space Complex in an attempt to revive the silent unmanned explorer, but there was no reply. As a result, the space agency announced today that is has discontinued the eight-month recovery effort and officially declared the Mars Exploration Rover's mission completed.

Today's announcement brings the final, suspenseful chapter of the Opportunity rover story to a close. In May 2018, Mars was engulfed in a global dust storm that blotted out the Sun for weeks in the area Opportunity was exploring. Because the rover is powered by solar panels, this deprived the systems of electricity, draining its batteries and forcing the craft into automatic shutdown.

On June 10, all contact was lost with Opportunity, but mission control remained hopeful that when the storm finally abated in September, the return of the Sun would recharge the batteries and reawaken the spacecraft. However, no signals were received and it was feared that the solar panels were coated with dust.

Still remaining optimistic, NASA engineers decided to wait through the local "dust-clearing season" in hopes that rising winds would clear the panels. Unfortunately, that season has passed and the local winter is approaching. The fear is that the prolonged blackout drained the batteries too much, and that the spacecraft's systems have been damaged. Even if Opportunity is still theoretically functional, the intense winter cold will almost certainly put paid to the batteries and electronics.

During the past few weeks, NASA implemented a more aggressive rescue effort, not only sending standard signals and awaiting a reply, but also transmitting direct commands for Opportunity to switch to its back-up X-band radio, reset its clock, and send a reply via UHF radio. There was no response.

Despite the end of the rescue effort, NASA remains upbeat. At a press conference today, the space agency's representatives preferred to focus on the successes of the mission rather than its end. One of two identical rovers sent to Mars, Opportunity landed in the Meridiani Planum region on January 24, 2004, after a seven-month voyage from Cape Canaveral Air Force Station in Florida.

Opportunity and its twin, Spirit, were designed to operate for 90 Martian days and traverse a total distance of 1,100 yards (1,000 m). Instead, it continued to operate for almost 15 years and covered 28 miles (45 km), during which it discovered geological features pointing to the watery past of ancient Mars, including traces of hematite and indications that Endeavour Crater may have once contained drinkable water. Spirit, meanwhile, succumbed to the Martian environment in May 2011 after getting stuck in a sand dune.

"It is because of trailblazing missions such as Opportunity that there will come a day when our brave astronauts walk on the surface of Mars," says NASA Administrator Jim Bridenstine. "And when that day arrives, some portion of that first footprint will be owned by the men and women of Opportunity, and a little rover that defied the odds and did so much in the name of exploration."

The video below recaps the Opportunity mission.

Source: NASA

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