When JAXA’s Hayabusa-2 spacecraft delivered samples from asteroid Ryugu to Earth in late 2020, anticipation was high. What could the space rock possibly be waiting to tell us?

Asteroids are time capsules of the Solar System, containing material from early in its history. As a 2021 study found, the Ryugu samples contained carbon, nitrogen, and oxygen, all necessary ingredients for life, and a 2022 study discovered evidence of water (and possibly a subsurface lake) that had long since dried up. Ryugu and its parent body were also revealed to carry some of the most ancient rocks in the Solar System. However, the pieces of this asteroid still had more to say.

It turned out that two of the Ryugu samples each had a shard of something that visually stood out. Researchers discovered they were seeing fragments, or clasts, of rock with a chemical composition that differed from the rest of Ryugu. These clasts were higher in sulfur and iron, but lower in oxygen, magnesium, and silicon. That meant they could not have possibly formed with Ryugu, so they had to have been acquired through a later impact; but the asteroid still had more to say.

Embedded in the clasts were tiny grains of rock made from stars that died before the Sun ever existed. “[The chemical makeup of] the primitive clasts compared to bulk Ryugu suggest that the clasts formed in a unique part of the protoplanetary disk enriched in presolar materials,” the research team said in a study recently published in Science Advances.

UPDATE, Aug. 4, 2023: NASA has reestablished full communications with Voyager 2.

Key takeaways

NASA’s DART mission crashed a spacecraft into the nearby asteroid Dimorphos to test a possible strategy for deflecting asteroids that are headed for Earth.
The test succeeded in knocking Dimorphos slightly off course but also dislodged from its surface 37 boulders that are now moving away from the asteroid.
The effort reveals an unintended consequence of technology to deflect asteroids on a collision course with Earth: Smaller rocks flying off into space could create their own problems.

In 2020, the Indian Space Research Organization (ISRO) estimated the Chandrayaan-3 mission would cost about $75 million.