NASA’s efforts to bring Martian rocks to Earth could provide insights into the possibility of past life on Mars—but first, they need to transport those samples back home.

For several years, the Perseverance rover, part of the U.S. space agency, has been exploring Mars and collecting intriguing rock samples. Some are securely stored in cylindrical tubes on the Martian surface, while others are safely held within the rover itself.

Both NASA and the European Space Agency have aspired to return some of these rocks to Earth for detailed examination. However, with mounting costs and delays, the ambitious plan to achieve this by the 2030s was beginning to seem out of reach.

As a result, the agency decided to pause a few months back to reassess the situation.

Currently, it seems the ultimate decision about how to retrieve these Martian rocks will be made by President-elect Donald Trump’s administration.

This month, outgoing NASA Administrator Bill Nelson and other officials shared two potential plans for the Mars Sample Return mission with the incoming administration. This means that when Trump takes office on Monday, his likely appointee to lead NASA—billionaire entrepreneur and private astronaut Jared Isaacman, who led the Polaris Dawn mission last year—will have considerable influence on the final outcome.

While robotic missions have successfully returned samples from the moon and asteroids, a successful Mars project would represent the first time rocks from another planet have returned to Earth. Once in the possession of scientists, there is hope that studying these samples will shed light on the geological history of Mars and investigate the possibility of past life.

“NASA’s rovers are enduring Mars’ harsh environment to gather invaluable scientific samples,” said Nicola Fox, associate administrator of NASA’s Science Mission Directorate, in a statement. “We are eager to bring those back as soon as possible for analysis in cutting-edge facilities.”

Here’s everything you need to know about the Mars rock samples, possible plans for their return, and what’s next for Perseverance:

What exactly are the Mars rock samples?

In July 2020, the Perseverance rover embarked on a 200-day, 300-million-mile journey to reach Mars. After landing in February 2021 in the Jezero Crater, the rover, which is remotely operated from Earth, has spent nearly four years exploring and collecting over two dozen rock samples—many of which are stored in the first-ever depot on another planet for retrieval by NASA and ESA in the future.

The Jezero Crater, believed to have formed 3.9 billion years ago due to a significant impact, is one of the most promising locations on Mars for finding evidence of ancient life.

Perseverance’s expeditions have provided some insights into the puzzling Martian geology, but nothing compares to what can be discovered through detailed studies of rocks using state-of-the-art equipment. Though Mars rocks occasionally reach Earth as meteorites, such instances are rare, and those samples are altered during their fiery passage through the atmosphere.

For these reasons, NASA and the ESA are committed to bringing back the untainted Mars rocks collected by Perseverance.

“These samples could transform our understanding of Mars, the universe, and ultimately, ourselves,” Nelson remarked in a statement.

NASA’s two proposals for returning Martian rocks

To keep the ambition of retrieving Mars samples by the 2030s alive, NASA explored alternative strategies in April 2024, seeking solutions to the approximately $11 billion plan they had initially pursued.

After reviewing 11 proposals submitted to NASA in September, the agency formed a committee to finalize recommendations. On January 7, NASA unveiled two mission proposals that could reduce costs to estimated figures between $6 and $7 billion, which agency officials believe have the best chance of ensuring that the samples are returned prior to any human missions to Mars.

The traditional approach would utilize a sky crane system—similar to the technique used to lower NASA’s Perseverance and Curiosity rovers onto Mars via cables. The alternative proposal would involve a landing system created by private firms.

In both scenarios, the number of spacecraft and launches would remain unchanged, with an orbiter designed by the European Space Agency responsible for transporting the rocks back. NASA stated that the proposed plans would simplify the mission overall.

A final decision is expected by the second half of 2026 after engineering studies are conducted on each plan’s specifics.

“Exploring these two potential paths will ensure that NASA can successfully bring these samples back from Mars while saving both costs and time,” said Nelson.

What’s next for Perseverance on Mars?

Meanwhile, the exploration for Martian rocks by Perseverance is far from finished.

After years of operations in Jezero, the rover finally reached the summit of the steep Martian crater in December, marking the start of its next exploration phase.

Perseverance commenced its gradual ascent in August 2024 to the top of the crater, which scientists believe was once submerged in water. This challenging climb, which took over three months, was filled with obstacles, but also moments of discoveries as the six-wheeled rover paused to survey its surroundings.

Upon reaching the rim, the rover now faces a quarter-mile journey to another site where orbital data indicates the presence of light-toned, layered bedrock, according to NASA. In the upcoming year, the rover is scheduled to explore up to four locations within a four-mile stretch on the northern part of Jezero’s southwestern rim.

During the initial phase at the crater’s base, the focus was on searching for rocks that may have partially filled the crater during its formation. Now, Perseverance will seek out rocks thought to have originated from deep within Mars, which were ejected upward to contribute to the rim after the impact that formed the crater.

Eric Lagatta covers breaking and trending news.