Neanderthals and humans likely mixed and mingled during a narrow time frame 45,000 years ago, scientists reported Thursday.

Researchers analyzed ancient genes to pinpoint the time period, which is slightly more recent than previous estimates for the mating.

Modern humans emerged in Africa hundreds of thousands of years ago and eventually spread to Europe, Asia, and beyond. Somewhere along the way, they met and mated with Neanderthals, leaving a lasting fingerprint on our genetic code.

Scientists don’t know exactly when or how the two groups entangled. But ancient bone fragments and genes are helping scientists figure that out.

“Genetic data from these samples really helps us paint a picture in more and more detail,” said study co-author Priya Moorjani at the University of California, Berkeley.

The research was published Thursday in the journals Science and Nature.

To pin down the timeline, researchers peeked at some of the oldest human genes from the skull of a woman, called Zlatý kůň or Golden Horse, named after a hill in the Czech Republic where it was found. They also examined bone fragments from an early human population in Ranis, Germany, about 140 miles (230 kilometers) away. They found snippets of Neanderthal DNA that placed the mating at around 45,000 years ago.

In a separate study, researchers tracked signs of Neanderthal DNA in our genetic code over 50,000 years. They found Neanderthal genes related to immunity and metabolism that may have helped early humans survive and thrive outside of Africa.

We still carry Neanderthals’ legacy in our DNA. Modern-day genetic quirks linked to skin color, hair color, and even nose shape can be traced back to our extinct former neighbors. And our genetic code also contains echoes from another group of extinct human cousins called Denisovans.

Future genetic studies can help scientists detangle exactly what—and who—we’re made of, said Rick Potts, director of the Smithsonian’s Human Origins program, who was not involved with the new research.

“Out of many really compelling areas of scientific investigation, one of them is: well, who are we?” Potts said.

NASA has postponed the first crewed landing of the program until mid-2027, delaying the following two Artemis trips to the moon.

After identifying the primary cause of Orion heat shield erosion on the Artemis 1 mission two years ago, NASA leadership announced at a news conference on December 5 that they were postponing the Artemis 2 and 3 flights.

Artemis 2, which was originally planned to launch in September 2025, would now debut in April 2026 under the updated schedule. It will be the first crewed voyage of Orion to take four astronauts from the United States and Canada around the moon.

As a result, Artemis 3, which will use SpaceX’s Starship vehicle for the first crewed landing of the entire exploration effort, will be delayed. Originally scheduled for September 2026, that mission is now anticipated to occur in mid-2027.

Following an examination of Artemis 1’s heat shield deterioration, NASA changed that timeline. In October, agency representatives claimed to have identified the cause of the heat shield material’s release, but they did not elaborate on the cause or NASA’s plans to fix it.

NASA Deputy Administrator Pam Melroy said the issue was related to Orion’s “skip” reentry, in which the capsule enters and exits the atmosphere to release energy. In the outer layers of the heat shield, more heat was retained than anticipated, resulting in trapped gases. “This caused internal pressure to build up and led to cracking and uneven shedding of that outer layer,”  she said.

This judgment was confirmed by an independent review panel after a thorough study. “There were a lot of links in the error chain that accumulated over time that led to our inability to predict this in ground tests,” stated Amit Kshatriya, deputy assistant administrator of NASA’s Moon to Mars Program Office. This included modifications to the shape of the material blocks and modifications to the manufacturing process of the heat shield material, known as Avcoat.

He said that in areas of the Avcoat material with the required greater permeability to let the gasses out, that was verified. “In those places, we did not witness in-flight cracking, and that was the key clue for us.”

NASA will alter the reentry profile, including shortening the skip phase of the reentry, rather than replacing the entire heat shield for the Artemis 2 mission. According to ground tests, those adjustments should be enough to prevent material from breaking off as a result of cracking.

The agency has been working on a number of other Orion issues while looking into the heat shield issue, such as a battery issue that was reported in January but was reportedly fixed, according to Kshatriya.

Despite an upcoming presidential transition that would probably rethink the entire Artemis design, agency chiefs said they made the decision immediately to prevent future delays. “We’re on a day-for-day slip. We had to make this decision,” Melroy stated. “If you’re waiting for a new admininstrator to be confirmed and a team to come up to speed on all this technical work we’ve all been tracking very closely, I think that would be actually far worse.”

Shortly after President-elect Donald Trump stated on December 4 that he would select Jared Isaacman to oversee the agency, NASA Administrator Bill Nelson claimed he spoke with Isaacman. He did, however, add that he and other authorities had a discussion prior to the meetings in which they confirmed the revised plan for Artemis 2 and 3. Melroy went on to say that NASA could have been consulted on the decision, but the incoming administration has not dispatched a transition team there.

Nelson, however, maintained that the present architecture was still the most effective way to send humans back to the moon in spite of the problems and delays, pointing out that even with the most recent postponement, NASA would still make a lunar landing before China’s projected 2030 lunar mission.

“Are they going to axe Artemis and insert Starship?” In reference to the impending Trump administration, Nelson stated. Only Orion is rated for human spaceflight outside of Earth’s orbit, he said. “I expect that this is going to continue.”

The first lunar lander mission is scheduled to launch in January, according to Firefly Aerospace. This means that none of the three commercial lander missions that were originally scheduled to launch in the fourth quarter of this year will actually launch.

On Nov. 25, Firefly said that it would launch its Blue Ghost 1 lander mission over the course of six days in mid-January. A SpaceX Falcon 9 will take out from Florida with the spacecraft.

After the spacecraft finished testing at NASA’s Jet Propulsion Laboratory in October, the launch date was announced. In the release confirming the launch date, Firefly CEO Jason Kim remarked, “Blue Ghost aced environmental testing and proved the lander is performing 100% as expected.” “While we know there will be more challenges ahead, I’m confident this team has what it takes to softly touch down on the lunar surface and nail this mission.”

The spacecraft’s launch was initially scheduled for the fourth quarter of 2024, but the corporation did not provide a precise date. Joseph Marlin, the principal engineer of Firefly’s Elytra Dark spacecraft, again suggested a fourth-quarter launch date during a Lunar Exploration Analysis Group (LEAG) conference on October 29. However, he stated that he was unable to provide more precise details, implying that it depended on the availability of launch vehicles. At that time, he stated, “SpaceX is still sorting out its schedule,”

The company’s first lunar lander mission is called Blue Ghost. Through the Commercial Lunar Payload Services (CLPS) program, the spacecraft will transport ten NASA payloads. In February 2021, Firefly received a $93.3 million task order from NASA for the mission, which was initially scheduled for launch in 2023. Whether the spacecraft is carrying any non-NASA payloads has not been disclosed by Firefly.

The corporation has named the mission “Ghost Riders in the Sky,” and it will run for roughly 60 days. The spacecraft will first operate in phasing orbits around the Earth for 45 days before traveling to the moon and putting into orbit. The spacecraft will land close to Mons Latreille, a volcanic formation in Mare Crisium on the moon’s northeastern near side. The lander is intended to stay in operation for several hours into the lunar night and throughout the whole two-week lunar day.

Up to three commercial lunar lander missions were originally scheduled to launch in the fourth quarter of this year, but none of them will now. In a financial announcement for its fiscal second quarter, the Japanese company iSpace said on November 12 that its Mission 2 lunar lander, which was previously scheduled to launch in December, will instead launch no early than January. The lander will launch on a SpaceX Falcon 9, just as Firefly.

During a Nov. 14 earnings call, Intuitive Machines revealed that its IM-2 mission, which had been aiming for a December or early January launch, will now launch on a Falcon 9 no earlier than February. The business did not provide an explanation for the slip.

However, Firefly might still be beaten to the moon’s surface by Intuitive Machines. The IM-2 mission will land around a week after launch, following a more direct path to the moon than the IM-1 mission, which launched in February 2024. According to Firefly’s Marlin, who spoke at the LEAG meeting, the two businesses have been talking about ways to deconflict their landings, such as making sure that communications don’t conflict.Firefly plans to launch its first lunar lander mission in January.