162173 Ryugu (provisional designation
1999 JU3) is a near-Earth object and a potentially hazardous asteroid of the Apollo group. It measures approximately 900 metres (3,000 ft) in diameter and is a dark object of the rare spectral type Cb, with qualities of both a C-type asteroid and a B-type asteroid. In June 2018, the Japanese spacecraft
Hayabusa2 arrived at the asteroid. After making measurements and taking samples,
Hayabusa2 left Ryugu for Earth in November 2019 and returned the sample capsule to Earth on 5 December 2020. The samples showed the presence of organic compounds, such as uracil (one of the four components in RNA) and vitamin B3.