NASA will formally abandon Mars Opportunity mission

A heavy spacecraft would need rockets for braking and steering but could also be flown to steer itself through lift

"I was there with the team as these commands went out into the deep sky, and I learned this morning that we had not heard back and Opportunity remained silent", said Thomas Zurbuchen, NASA associate administrator for space science.

Opportunity and its twin rover, Spirit, conclusively showed that Mars once enjoyed a warmer, wetter environment with flowing water at the surface - an environment researchers now know was habitable in the distant past.

InSight landed safely on Mars on November 26, kicking off a two-year mission to explore the deep interior of the Red Planet.

The golf cart-size Opportunity outlived its twin, the Spirit rover, by several years. But with winter setting in at Opportunity's location, the team determined that the Martian nights were getting too cold for the electronics to survive.

Opportunity was the fifth of eight NASA space vehicles that have successfully landed on Mars. By February 6, NASA reported that more than 835 recovery commands had been sent to the rover over a span of frequencies, including those outside its normal communications range.

The scientist said the machine "has given us a larger world".

While some NASA spacecraft have endured for longer than 15 years, those are orbiter or flyby missions-they're not encountering the sheer number of hazards Opportunity did on the ground.

"When I think of Opportunity, I will recall that place on Mars where our intrepid rover far exceeded everyone's expectations", John Callas, manager of the Mars Exploration Rover (MER) project at JPL said. And so some argued that Opportunity - affectionately known as "Oppy" by some - wasn't being given the same chance. Instead, the rover has persisted for 15 years, sending back incredible data and photos from Mars to help unravel the Red Planet's secrets.

Opportunity was exploring Mars' Perseverance Valley, fittingly, when the fiercest dust storm in decades hit and contact was lost.

Cornell University's Steve Squyres, lead scientist for both Opportunity and Spirit, considers succumbing to a ferocious storm an "honourable way" for the mission to end. It's been suggested by some on the team that Curiosity may not ever get the same life span, and Mars 2020 (you can guess when NASA intends to launch it) is a lot like an upgraded Curiosity. By consistently actively pinging the rover during both preplanned recovery times and other random intervals, engineers had hoped to catch Opportunity during an awake period.

"We found.evidence that yes, there was liquid water", says Fraeman.

"For the public the big change was that Mars became a dynamic place, and it was a place that you could explore every day", Emily Lakdawalla, an expert on space exploration and senior editor at The Planetary Society.

The programme has had an extraordinary record of success: 45.2km traversed, more than the Soviet Union's Lunokhod 2 moon rover during the 1970s and more than the rover that United States astronauts took to the moon on the Apollo 17 mission in 1972. Together they landed on Mars the following year on a quest to determine the history of the water on the planet, NASA said on their website.

The nostalgia extended across the generations of scientists who have handled the plucky little adventurer. And it's the technical legacy of the Mars Exploration Rovers, which is carried aboard Curiosity and the upcoming Mars 2020 mission. Zurbuchen was present Tuesday night during a final planned attempt to reach the rover Tuesday evening, asking the rover to respond.