A space probe of the US National Aeronautics and Space Administration, or NASA, called Osiris-Rex has gone into orbit around an ancient asteroid, The Guardian reported on Tuesday. It marked the closest ever orbit of the smallest ever celestial object.

The spacecraft entered into orbit around Bennu, 110 million km from Earth, on Monday. It is the smallest celestial body ever to be orbited by a spacecraft. Osiris-Rex is barely more than a km above the asteroid’s surface.

The spacecraft arrived at Bennu in early December and flew in formation with it till this latest manoeuvre. Its objective is to descend to the surface, collect samples from the asteroid and return to Earth in 2023.

Meanwhile, the space agency is waiting to hear from its New Horizons spacecraft to confirm that it has successfully flown by Ultima Thule – the most distant world ever studied by humanity, BBC reported. A confirmation signal is expected around 8.15 pm Indian Standard Time.

Ultima Thule is an icy, ancient rock in the Kuiper Belt about 1.6 billion km beyond Pluto or 6.4 billion kilometres from Earth. Studying it may reveal how planets formed, Al Jazeera reported. The flyby comes three-and-a-half years after New Horizons flew past Pluto and provided us with the first close-up photographs of the dwarf planet.