(CNN) It's time to say goodbye to Opportunity. The Mars rover's team made its last attempt to contact Opportunity on Tuesday night, and it went unanswered. On Wednesday, NASA confirmed that the mission is over.
The agency held a news conference to detail the results of recovery efforts since a dust storm encircled Mars last year.
"For more than a decade, Opportunity has been an icon in the field of planetary exploration, teaching us about Mars' ancient past as a wet, potentially habitable planet and revealing uncharted Martian landscapes," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate. "Whatever loss we feel now must be tempered with the knowledge that the legacy of Opportunity continues, both on the surface of Mars with the Curiosity rover and InSight lander and in the clean rooms of [NASA's Jet Propulsion Laboratory], where the upcoming Mars 2020 rover is taking shape."
Mars Opportunity and Spirit rovers
This image is a cropped version of the last 360-degree panorama taken by the Opportunity rover's panoramic camera from May 13 through June 10, 2018. The view is presented in false color to make some differences between materials easier to see.
Are those Martian blueberries? These tiny spherules pepper the sandy surface in this 3-centimeter (1.2-inch) square view of the Martian surface. Opportunity took this image while the target was shadowed by the rover's instrument arm.
From its perch high on a ridge, Opportunity recorded this image of a Martian dust devil twisting through the valley below. Just as on Earth, a dust devil is created by a rising, rotating column of hot air. When the column whirls fast enough, it picks up tiny grains of dust from the ground, making the vortex visible.
While traversing on and around the ancient volcanic feature called Home Plate, Spirit took many images of finely layered and more frothy looking volcanic rocks.
Opportunity photographed its tracks in the soft sand between the Endurance and Victoria craters on the Meridiani Plains.
More blueberries! Opportunity took this photo in 2004 of a rock called "Last Chance." The spherules embedded in the rock reminded the researchers of berries in muffins. The textures in the rock actually helped researchers determine that Mars had wet environmental conditions in the past.
Oppy's panoramic camera gathered this mosaic in 2014 of Wdowiak Ridge, as well as the rover's tracks to the right. This is about 70 degrees from north/northwest to east/northeast, showing the 500-feet ridge that rises 40 feet tall.
The rover took a selfie to show how much dust it had accumulated in 2011 before the windy season helped knock some of it off.
Sometimes, when Opportunity's solar power was limited, it would stop between treks to different features on Mars. This 2010 photo of its tracks on the surface show it "hopping from lily pad to lily pad."
The Mars Reconnaissance Orbiter took this photo of Victoria Crater, about a half-mile in diameter. It was Opportunity's home for 14 of the first 46 months it spent on Mars.
Opportunity's panoramic camera took this photo of outcrop rocks that it encountered on its journey in 2005. Cracks and other features are obvious. The two holes visible were drilled by the rover to expose the underlying material.
A shadow selfie. On July 26, 2004, the rover took this photo commemorating its 90 days on Mars -- the amount of time the mission was supposed to last. Instead, it continued for 15 years.
Opportunity made an impact. A panoramic image shows the heat shield impact site when it landed in 2004.
This iron meteorite was the first meteorite of any type ever found on another planet. The basketball-sized meteorite is rich in iron and nickel, and Opportunity found it in 2005.
Endurance Crater and its tendrils of sand presented a beautiful photo chance for the rover in 2004. Mars is full of dunes, and this is just one example Opportunity encountered.
These pointy features were called "Razorback." They're only a few centimeters tall, but the chunks of rock were found sticking up at the edge of flat rocks in Endurance Crater. They may have formed when fluids moved through rock fractures.
In 2010, Opportunity took this panorama of the eastward horizon view of Endeavour Crater's rim.
The Mars Spirit rover was Opportunity's twin, and it's mission ended in 2011. Both rovers featured a piece of metal with the American flag on the side. They are made of aluminum recovered from the site of the World Trade Center towers in New York City.
These two views from NASA's Curiosity rover -- from June 7, left, and June 10 2018 -- show how dust increased over three days from a major Martian dust storm that became planet-encircling on June 20, 2018. Opportunity was stranded in the middle of the storm and wasn't heard from afterward.
NASA's Opportunity rover appears as a blip in the center of this square. This image taken by HiRISE, a high-resolution camera on board NASA's Mars Reconnaissance Orbiter, showed the dust storm over Perseverance Valley had substantially cleared.
Solar-powered Opportunity hasn't communicated with engineers since June 10. Dust has blocked out sunlight, and even the expected winds from November through January haven't helped clear Opportunity's sensors and panels. Engineers tried different things to revive Opportunity, sending repeated signals and commands to attempt to fix other potential issues. They've sent more than 835 recovery commands that remain unanswered.
"We have made every reasonable engineering effort to try to recover Opportunity and have determined that the likelihood of receiving a signal is far too low to continue recovery efforts," said John Callas, manager of the Mars Exploration Rover project at NASA's Jet Propulsion Laboratory.
The team is grateful for the long mission but sad to say goodbye. "Science is an emotional affair. It's a team sport, and that's what we're celebrating today," Zurbuchen said.
When Opportunity's twin, Spirit, became mired in soft soil in 2009 and its five working wheels couldn't free the rover, NASA held a "service" to commemorate the end of the mission in May 2011.
"Oppy," as the rover is affectionately known, has well outlasted her original 90-day mission. Instead, the rover has persisted for 15 years, sending back incredible data and photos from Mars to help uncover the Red Planet's secrets.
Opportunity and Spirit launched in 2003 and landed on Mars in 2004, searching for signs of ancient life.
Opportunity found hematite at its landing site: little round things all over the ground that looked like blueberries. These features form in water, a definitive sign to NASA that liquid water had been on the surface of Mars.
Opportunity was expected to travel 1,100 yards over 90 days on Mars. Instead, it traveled 28 miles.
It landed in Eagle Crater, moved on to Endurance Crater and planned to visit Victoria Crater. But the rover got stuck in the dunes of windblown material on the Martian surface. The engineers put it in reverse and "gunned it" to free the rover.
Opportunity was able to visit Victoria and spend two years driving around it and inside it before moving on to Endeavour Crater and ending in Perseverance Valley.
Opportunity's mission has led to many discoveries about the Red Planet, but perhaps the most exciting was when the rover found evidence that Mars once had water and supported conditions for sustaining microbial life.
"From the get-go, Opportunity delivered on our search for evidence regarding water," said Steve Squyres, principal investigator of the rovers' science payload at Cornell University. "And when you combine the discoveries of Opportunity and Spirit, they showed us that ancient Mars was a very different place from Mars today, which is a cold, dry, desolate world. But if you look to its ancient past, you find compelling evidence for liquid water below the surface and liquid water at the surface."
The best photos of Mars
This perspective of Mars' Valles Marineris hemisphere from July 9, 2013, is actually a mosaic comprising 102 Viking Orbiter images. At the center is the Valles Marineris canyon system, over 2,000 kilometers long and up to 8 kilometers deep.
This 2016 self-portrait of the Curiosity Mars rover shows the vehicle at the Quela drilling location in the Murray Buttes area on lower Mount Sharp.
A photo of a preserved river channel on Mars, taken by an orbiting satellite, with color overlaid to show different elevations. Blue is low and yellow is high.
Although Mars isn't geologically active like Earth, surface features have been heavily shaped by wind. Wind-carved features such as these, called yardangs, are common on the Red Planet. On the sand, the wind forms ripples and small dunes. In Mars' thin atmosphere, light is not scattered much, so the shadows cast by the yardangs are sharp and dark.
The European Space Agency's Mars Express mission captured this 2018 image of the Korolev crater, more than 50 miles across and filled with water ice, near the north pole.
InSight's seismometer recorded a "marsquake" for the first time in April 2019.
The Mars Reconnaissance Orbiter used its HiRISE camera to obtain this view of an area with unusual texture on the southern floor of Gale Crater.
Cooled lava helped preserve a footprint of where dunes once moved across a southeastern region on Mars. But it also looks like the "Star Trek" symbol.
These small, mineral hematite-rich concretions are near Fram Crater, visited by NASA's Opportunity rover in April 2004. The area shown is 1.2 inches across. The view comes from the microscopic imager on Opportunity's robotic arm, with color information added from the rover's panoramic camera. These minerals suggests that Mars had a watery past.
This image shows seasonal flows in Valles Marineris on Mars, which are called Recurring Slope Lineae, or RSL. These Martian landslides appear on slopes during the spring and summer.
Mars is known to have planet-encircling dust storms. These 2001 images from NASA's Mars Global Surveyor orbiter show a dramatic change in the planet's appearance when haze raised by dust-storm activity in the south became globally distributed.
Curiosity took images in September 2015 of Mount Sharp, a hematite-rich ridge, a plain full of clay minerals to create a composite and rounded buttes high in sulfate minerals. The changing mineralogy in these layers of Mount Sharp suggests a changing environment in early Mars, though all involve exposure to water billions of years ago.
From its perch high on a ridge, Opportunity recorded this 2016 image of a Martian dust devil twisting through the valley below. The view looks back at the rover's tracks leading up the north-facing slope of Knudsen Ridge, which forms part of the southern edge of Marathon Valley.
HiRISE captured layered deposits and a bright ice cap at the Martian north pole.
Mars is far from a flat, barren landscape. Nili Patera is a region on Mars in which dunes and ripples are moving rapidly. HiRISE, onboard the Mars Reconnaissance Orbiter, continues to monitor this area every couple of months to see changes over seasonal and annual time scales.
NASA's Curiosity rover captured its highest-resolution panorama, including more than a thousand images and 1.8 billion pixels, of the Martian surface between November 24 and December 1, 2019.
This image, combining data from two instruments aboard NASA's Mars Global Surveyor, depicts an orbital view of the north polar region of Mars. The ice-rich polar cap is 621 miles across, and the dark bands in are deep troughs. To the right of center, a large canyon, Chasma Boreale, almost bisects the ice cap. Chasma Boreale is about the length of the United States' famous Grand Canyon and up to 1.2 miles deep.
A dramatic, fresh impact crater dominates this image taken by the HiRISE camera in November 2013. The crater spans approximately 100 feet and is surrounded by a large, rayed blast zone. Because the terrain where the crater formed is dusty, the fresh crater appears blue in the enhanced color of the image, due to removal of the reddish dust in that area.
This dark mound, called Ireson Hill, is on the Murray formation on lower Mount Sharp, near a location where NASA's Curiosity rover examined a linear sand dune in February 2017.
Is that cookies and cream on Mars? No, it's just polar dunes dusted with ice and sand.
The cloud in the center of the image is actually a dust tower that occurred in 2010 and was captured by the Mars Reconnaissance Orbiter. The blue and white clouds are water vapor.
HiRISE took this image of a kilometer-size crater in the southern hemisphere of Mars in June 2014. The crater shows frost on all its south-facing slopes in late winter as Mars is heading into spring.
The two largest quakes detected by NASA's InSight appear to have originated in a region of Mars called Cerberus Fossae. Scientists previously spotted signs of tectonic activity here, including landslides. This image was taken by the HiRISE camera on NASA's Mars Reconnaisance Orbiter.
Taken by the Viking 1 lander shortly after it touched down on Mars, this image is the first photograph ever taken from the surface of Mars. It was taken on July 20, 1976.
Opportunity not only leaves behind a legacy of discovery, it became the longest-running rover and captured 217,594 raw images.
It will probably stay where it fell silent in Perseverance Valley. There, a historic global dust storm blackened the skies and starved its batteries of energy. The team listened for the rover every day, worrying as the skies continued to darken and the temperatures dropped. But the historic storm proved to be too much for Opportunity.
"I cannot think of a more appropriate place for Opportunity to endure on the surface of Mars than one called Perseverance Valley," said Michael Watkins, director of JPL. "The records, discoveries and sheer tenacity of this intrepid little rover is testament to the ingenuity, dedication and perseverance of the people who built and guided her."
This is the last image the panoramic camera captured before the rover communicated to engineers that its power was running low and that the dusty conditions were making things quite dark.
But Opportunity had shown other signs of age. 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. Then, the flash memory stopped, so the team had to recover the rover's data every day before it "forgot" what it saw.
Meanwhile, the Curiosity rover, which was unaffected by the storm, and the stationary InSight lander continue to study the Red Planet and carry on missions of discovery that were founded by Opportunity and Spirit.
Curiosity tweeted its farewell to Opportunity.
On Tuesday, InSight deployed its "mole," or heat flow probe, on the Martian surface, and in the coming weeks, it will be the first probe to go more than 16 feet below the surface. This will determine Mars' subsurface temperature and thermal conductivity.
InSight also shared a fond farewell to Opportunity on Twitter.
On Wednesday, Opportunity's team bid her farewell while looking to the foundations the mission laid.
"When I think of Opportunity, I will recall that place on Mars where our intrepid rover far exceeded everyone's expectations," Callas said. "But what I suppose I'll cherish most is the impact Opportunity had on us here on Earth. It's the accomplished exploration and phenomenal discoveries. It's the generation of young scientists and engineers who became space explorers with this mission. It's the public that followed along with our every step. And it's the technical legacy of the Mars Exploration Rovers, which is carried aboard Curiosity and the upcoming Mars 2020 mission.
"Farewell, Opportunity, and well done."
And one day, NASA hopes rover tracks will be alongside human footprints on the Red Planet.
"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," NASA Administrator Jim Bridenstine said. "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."