These are the haunting last images from NASA's Opportunity rover on Mars

NASA's Opportunity rover landed on the surface of Mars on January 25, 2004. Over its mission, it explored the planet and helped scientists make key discoveries. This includes the discovery that Mars once had large amounts of surface water and may have been habitable.

Opportunity successfully operated for almost 15 years before it stopped communicating with Earth. Here's a look at the last image the rover sent home. 

Mars gets seasonal dust storms, and these storms often last weeks while moderately cutting the sunlight that reaches the ground. In mid-2018, Opportunity faced a much bigger one. A storm began enveloping the planet on June 10 and lasted for months. It also reduced the light to just 0.002 percent of its usual level. 

Bill Nelson, chief of the mission's engineering team at NASA's Jet Propulsion Laboratory (JPL), described, "If you were there, it would be late twilight."

Opportunity couldn't generate enough power under those conditions. It tried to hibernate through the storm by entering safe mode. But when the storm finally eased in late 2018, the rover didn't wake up. 

NASA kept trying to reach it for more than half a year. After more than a thousand commands, engineers made their last attempt, and in February 2019 the space agency announced that it would stop trying. The rover's final communication had arrived on June 10, 2018.

The last images Opportunity took are two small thumbnails, which are usually sent ahead of the full-size versions. They came from the left and right eyes of its panoramic camera, around 9:33 a.m. PDT on June 10, 2018. 

Each one shows a faint dot of the Sun. Scientists used them to estimate "tau," which is a measure of how opaque the atmosphere is. Tau was about 10.8 that day, and this meant that only a tiny amount of sunlight was getting through.

The full-size versions of those two Sun images never arrived. The last image Opportunity actually sent was a partial frame of a dark sky. It was supposed to show Perseverance Valley, but the image came through as darkness and static. 

The blackness you see in the image actually comes from the storm. The white specks are camera noise, which appears in every image but is easier to see in the dark. The black bar at the bottom marks data that was never received.

According to science reporter Jacob Margolis, scientists at NASA said the last message they received from Opportunity effectively translated to, "My battery is low, and it's getting dark."

"This is a hard day," project manager John Callas said. "Even though it's a machine and we're saying goodbye, it's still very hard and very poignant, but we had to do that. We came to that point." Interestingly, NASA has published its "Opportunity, Wake Up!" playlist on Spotify. It includes many famous hits, like "Wake Me Up Before You Go-Go" by Wham!, "I Will Survive" by Gloria Gaynor, and "I Won't Back Down" by Tom Petty.