If by unlucky chance OSIRIS-REX came up short on Tuesday, it can try two more times. The next attempt would be at a backup site named Osprey in January.
The collection of the asteroid sample is the climax of the $800 million mission, which launched four years ago. The spacecraft has been making detailed observations of Bennu — a rock as wide as the Empire State Building is tall — for two years, mapping features of its surface as small as a couple of inches wide. It even discovered that Bennu was shooting debris from its surface into space.
The mission’s controllers selected a spot inside a crater near Bennu’s north pole that they named Nightingale. The spacecraft, 20 feet wide and about the size of a sport utility vehicle, had to navigate carefully to the target site, which is only 26 feet in diameter. In addition, it had to avoid a wall of rocks on the eastern edge of the crater. That included a pointy pillar nicknamed Mount Doom, which is as tall as a two- or three-story building.
However, despite the risks, Nightingale offered the greatest potential scientific payoffs, with unobstructed fine-grained material that appears to contain carbon-rich minerals.
Asteroids, mostly located in orbits between Mars and Jupiter, are bits that never coalesced into a planet, and planetary scientists hope that the samples from Bennu could shed light on what the young solar system was like when it formed 4.5 billion years ago. Asteroids like Bennu, which possesses carbon-rich minerals, may have provided the building blocks for life to arise on Earth.
The asteroid is also being studied because its orbit could cause it to collide with Earth late in the 22nd century. The likelihood of such an occurrence is low, and the asteroid is not large enough to end human civilization should it occur.
OSIRIS-REX — the name is a shortening of Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer — is to leave the asteroid next year and drop off the sample, which will parachute to a landing in Utah on Sept. 24, 2023.