NASA said goodbye on Wednesday to the longest-lasting rover ever to leave Earth to capture the surface of Mars, marking the end of an amazing era for the agency’s exploration of the red planet.

NASA declared its Opportunity rover “dead” on Wednesday. The Mars rover been quiet since June, when a dust storm had prevented Opportunity’s solar panels from generating enough power to keep itself awake, according to the New York Times.

There was still no reply when NASA made its last call Tuesday evening. The rover was only designed to last three months. It soared past those expectations and lasted more than 14 years, tens of millions of miles from Earth.

“It was an incredibly somber moment,” Tanya Harrison, a member of the mission’s science team who was present in Pasadena, Calif., told the New York Times about that final attempt.

According to the New York Times article, Opportunity landed on Mars on Jan. 24, 2004, three weeks after its twin, Spirit, set down on the opposite side of the planet. Spirit got stuck in a sand trap in 2009 and stopped communicating in 2010.

But Opportunity kept going for a total of 5,111 days, including the days until its last transmission. The New York Times noted in the article that a Martian day is roughly 40 minutes longer than an Earth day.

Experts expected that dust from the Martian air would block the solar panels and that the rovers would lose power, but gusts of wind on the red planet kept clearing the buildup. They lasted through winters by parking with their solar panels pointed toward the sun.

John L. Callas, the project manager for the mission, told the New York Times that part of their longevity was through their lithium ion batteries, which are similar to those now used in cellphones, laptops and electric cars.

“These rovers actually have the finest batteries in the solar system,” Callas told the New York Times. “We’d all be happy if our cellphone batteries lasted this long.”

Their incredible success lead to years of spectacular photos and data that was up-close, personal and straight from the Martian surface. Craters contained evidence of Mars transitioning from being once-habitable to harsh and volcanic, and how waters turned acidic as the entire planet dried out.

The New York Times spoke with some of the scientists that grew up with Opportunity’s extended journey, including Harrison, who was a college student when this mission first began.

“I never knew I would get to work on Opportunity 15 years later,” she told the New York Times.

These two Mars rovers became fascinations for the same scientists that are now pushing forward with more missions. The Curiosity rover is still going strong since it landed on Mars in 2012. NASA is planning to launch another in 2020, the same year that China and a joint European-Russian collaboration are planning to send their own rovers, according to the New York Times.

The men and women who worked to keep Spirit and Opportunity alive and well did so spectacularly, and the future of space exploration is that much brighter for it.