Later this year, NASA will reveal never-before-seen morsels of the moon, the agency announced on Monday.

The astronauts of the Apollo missions that landed on the moon from 1969 to 1972 collected 842 pounds worth of lunar rocks, core samples, pebbles, sand and dust. Many of those samples were later opened on the ground. But three have remained sealed — their contents stashed away for nearly 50 years.

They were intentionally saved for a time when more advanced technology would allow planetary scientists on Earth to delve deeper into the moon’s mysteries.

“The technology available in the ’60s and ’70s wasn’t able to do what we can do now,” said Jessica Barnes, an astronomer soon to join the University of Arizona’s Lunar and Planetary Laboratory. “Now we can go to a mineral and we can look at the very fine details, down to almost the width of a human hair.”