NASA's OSIRIS-REx mission to the asteroid Bennu has already brought about a series of landmark moments for space exploration, not least of which is the fact that the rock currently stands as the smallest object ever orbited by a spacecraft. Not content with that, mission control has moved the probe into tighter and tighter loops around the asteroid, now setting a new record for the closest ever orbit of a planetary body.
OSIRIS-REx entered orbit around Bennu last New Year's Eve on a mission to study the asteroid and scoop up a sample to return to Earth. At the time, it was actually executing the tightest orbit around a planetary body, circling the asteroid at a distance of around a mile (1.6 km), gathering sharper and sharper images of its surface and uncovering new insights ahead of the sampling attempt.
It latest maneuver saw the probe zoom in to an orbit just 680 m (2,231 ft) from the surface and enter a new phase of the mission called Orbital B. The first fortnight of this stage of the mission will be used to study mysterious plumes of material being ejected from the surface, which were spied by the mission scientists in images from January. It will also snap images like this one, captured shortly after OSIRIS-REx slipped into its new orbit.
Once it has probed the mysteries behind these eruptions it will begin work mapping the entire asteroid with its suite of scientific instruments. This will be critical in helping the team select the best site for sample collection, a procedure that will involve blasting the surface with nitrogen gas and scooping up small pebbles with a sampling arm. The samples are due to return to Earth in September 2023.
For now, OSIRIS-REx will remain in its tight orbit until mid-August, at which point it will move out to a slightly larger orbit for further observations. Sample collection is expected to take place in mid-2020.
Source: NASA