"To have a 90-day mission last for 15 years, and then end as a outcome of one of the most ferocious dust storms to hit Mars in a very long time, we can walk away with our heads held high", Steve Squyres, a Cornell professor and principal investigator on the mission, told Gizmodo.
The solar-powered rover's demise was no surprise: It fell out of contact with controllers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., last June - due to a globe-girdling Martian dust storm that kept Opportunity from charging its batteries.
Its greatest achievement was discovering, along with Spirit, evidence that ancient Mars had water flowing on its surface and might have been capable of sustaining microbial life.
The agency held a news conference to detail the results of recovery efforts since a dust storm encircled Mars past year. The Washington Post quotes Squyres as saying that Mars "is a cold and desolate world today, but in the distant past, in the time that the rocks explored by Spirit and Opportunity were formed, it was a very different world".
The craft, which arrived at the Red Planet in July 2004, has been out of communication since last summer.
Since the storm, Nasa has tried to contact the machine through recovery commands 1,000 times.
Though hard for those who worked on Opportunity - some for all 15 years or longer - the mission was declared a huge success.
The notion that the briefing is expected to be a sad one rather than a "hey, maybe this little robot has a little longer to rove" one is bolstered by the fact that NASA administrator Jim Bridenstine will be on hand with the Mars Exploration Rover mission leadership and an engineer from the Mars 2020 rover team. RIP Oppy, you were the best rover that ever rovered. "But we want to remember the 14-and-a-half years of phenomenal exploration".
In that future age, will someone visit Opportunity's resting place?
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.
NASA will issue an update on Opportunity's status on Wednesday at 2pm EST (7pm GMT).
It survived a bad dust storm in 2007 and is now being closely watched to see if it can survive a massive storm that has an estimated opacity level of 10.8, a sharp increase from the earlier storm's 5.5 tau.
"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.
Opportunity has not been riled since last June when it was the victim of one of the most intense dust storms in decades. It had a heater that was draining energy, and the clock was scrambled by loss of power, so it didn't know when to sleep. Zurbuchen thanked the hundreds of scientists and engineers for working for nearly two decades on the mission. 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. Two of them are still working: Curiosity (which landed in 2012) and InSight (which only landed recently). Zurbuchen was present Tuesday night during a final planned attempt to reach the rover Tuesday evening, asking the rover to respond.