The spacecraft, which landed in the Utah desert around 4pm on Sunday, contained around 250g of rocks and dust collected from asteroid Bennu as part of the agency’s $1 billion Osiris-Rex mission.
Experts say the carbon-rich, near-Earth asteroid serves as a time capsule from the earliest history of the solar system.
In a flyby of Earth, Osiris-Rex parachuted the sample capsule from 63,000 miles (100,000km) out to cap a seven-year journey..
The capsule landed four hours later on a remote expanse of military land as the mothership set off after another asteroid.
“We have touchdown!” Flight Control announced.
Officials later said the orange striped parachute opened four times higher than anticipated — around 20,000 feet (6,100 meters) — which led to the early touchdown.
Scientists estimate the capsule holds at least a cup of rubble from the carbon-rich asteroid known as Bennu, but won’t know for sure until the container is opened. Some spilled and floated away when the spacecraft scooped up too much and rocks jammed the container’s lid during collection three years ago.
Japan, the only other country to bring back asteroid samples, gathered about a teaspoon in a pair of asteroid missions.
The pebbles and dust delivered represent the biggest haul from beyond the moon.
Preserved building blocks from the dawn of our solar system 4.5 billion years ago, the samples will help scientists better understand how Earth and life formed.
Osiris-Rex is already chasing after the asteroid Apophis and will reach it in 2029.
NASA’s plans to return samples from Mars are on hold after an independent review board criticised the cost and complexity. The Martian rover Perseverance has spent the past two years collecting core samples for eventual transport to Earth.
Ashley King, UKRI future leaders fellow, Natural History Museum, said: “Osiris-Rex spent over two years studying asteroid Bennu, finding evidence for organics and minerals chemically altered by water.
“These are crucial ingredients for understanding the formation of planets like Earth, so we’re delighted to be among the first researchers to study samples returned from Bennu.
“We think the Bennu samples might be similar in composition to the recent Winchcombe meteorite fall, but largely uncontaminated by the terrestrial environment and even more pristine.”
Dr Sarah Crowther, research fellow in the Department of Earth and Environmental Sciences at the University of Manchester, said: “It is a real honour to be selected to be part of the Osiris-Rex sample analysis team, working with some of the best scientists around the world.
“Sample return missions like Osiris-Rex are vitally important because the returned samples are pristine, we know exactly which asteroid they come from and can be certain that they are never exposed to the atmosphere so that important information is retained.”