The stream of particles collected from around the nucleus of Comet Wild-2 has been safely stowed for return to Earth.
US space agency scientists report the special scoop extended from their probe Stardust as it flew past the 5-km-wide "snowball" has retracted properly.
It was loaded into a canister six hours after the flyby and will be jettisoned into the Earth's atmosphere in 2006.
"The next time the sample return capsule is going to be opened is in a clean room," Nasa's Tom Duxbury said.
Researchers expect their studies of the samples grabbed 389 million km from Earth on Friday will give new insights into the construction of comets and the earliest history of the Solar System.
Chemical and physical information locked within the particles could be the record of the formation of the planets and the materials from which they were made.
Duxbury, the Stardust project manager, and his colleagues have had further time to study the 72 pictures and other information sent back to Earth by the probe in a data feed that lasted more than a day.
"These are the best images ever taken of a comet and there is a remarkable amount of information in those 72 pictures," Ray Newburn, the spacecraft's imaging team leader, said.
"Not only did we image jets of material spewing out from the comet but for the first time in history we can actually see the location of their origin on the surface of the comet."
The images reveal huge depressions on the surface of the mountainous ball of ice, rock and dust.
Scientists are uncertain if they are the craters left by other bodies which have hit the nucleus or sinkholes created after material has left the comet after being exposed to sunlight.
The mission team has commented on the rough ride Stardust received as it flew through the comet's coma. The probe was buffeted as it came as close at 240 km to the nucleus; particles were hitting Stardust's shields at more that six kilometres per second.
"We thought we would see a uniform increase in the number of particles the closer we came to the comet's nucleus and then a reduction," said Stardust's principal investigator, Don Brownlee.
"Instead, our data indicate we flew through a veritable swarm of particles and then there would be almost nothing and then we would fly through another swarm."