Dwarf Planet Ceres
Dawn arrived at Ceres on March 6, 2015. Ceres is a large, spherical object that is classified as a dwarf planet. Its radius is roughly 296 miles (476 km), which is small as solar system worlds go but large in terms of asteroid belt members. Ceres is actually the largest member of the asteroid belt. It rotates around its axis once every 9 hours. Scientists have spotted water vapor appearing periodically above Ceres, possibly from ice escaping from the dwarf planet's surface after impacts. You can see Dawn's photos of Ceres here.NEXT: Japan's Lost Procyon
Japan's Lost Procyon
Japan's Procyon, also known as Proximate Object Close flyby with Optical Navigation, launched with Hayabusa2 on Dec. 4, 2014. The probe was supposed to fly by the asteroid 185851 2000 DP107 in 2016 (as shown in the previous image, but a problem with the ion-thruster system on Procyon forced the Japan Aerospace Exploration Agency to abandon the mission. Procyon did, however, catch a glimpse of Comet 67P, the destination of the Rosetta mission.
NEXT: Japan's Hayabusa2
The Japanese Hayabusa2 spacecraft, a successor to Hayabusa, is in orbit around asteroid Ryugu, intended to eventually return a sample back to Earth. Hayabusa2 launched on Dec. 2, 2014, and arrived at Ryugu on June 27, 2018. It will deploy several probes on the surface and also pick up some samples to send back to Earth in late 2020.
NEXT: Asteroid 162173 Ryugu
Ryugu: Asteroid 162173
Hayabusa2 arrived at Ryugu in June 2018. Ryugu is another potentially hazardous near-Earth object. It has qualities of both a C-type asteroid and a G-type (rare carbonaceous) asteroid. It takes about 16 months to orbit the sun and is named after a magical underwater palace from Japanese folk stories. Previously, Ryugu had the provisional designation of 1999 JU3.
NEXT: Spacecraft OSIRIS-Rex
NASA's OSIRIS-Rex (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) is a mission that launched on Sept. 8, 2016, en route to 101955 Bennu, a C-type asteroid. The spacecraft is expected to meet up with Bennu in August 2018 and then bring a sample back to Earth in September 2023.
NEXT: Asteroid Bennu (1999 RQ36)
Asteroid Bennu (1999 RQ36)
But what will NASA's OSIRIS-Rex show us about Bennu after arriving? We'll just have to wait and see!