target, Bennu, the asteroid grew in detail from a few tiny pixels

to an incredibly hi-resolution image. OSIRIS-REx confirmed the

asteroid’s basic shape, which was originally observed in 1999

by ground-based radar at Arecibo Observatory. What scientists

didn’t expect was just how rough and boulder-filled the asteroid

would turn out to be. While it can be difficult to fully grasp

Bennu’s unfamiliar surface, it’s helpful to understand the scale

of what you’re seeing here. In this image, the brightest

boulder is the length of a horse and the large boulder in this

image is the width of a soccer field. Another challenge for the

mission is the asteroid’s small size and weak gravity. This

means that OSIRIS-REx needs to fly daringly close to the

surface in order to enter into orbit. With its orbital A phase,

OSIRIS-REx successfully entered the closest-ever orbit for a

spacecraft, setting a Guinness World Record in the process.

Then, 6 months later, it beat its own record during its

orbital B phase and approached to within a few hundred meters

of the rocky surface. Because OSIRIS-REx flew so closely over

the surface during orbital B, the team was able to map the

topography and shape of Bennu better than we have our own

Moon. In addition to mapping Bennu, OSIRIS-REx plans to

collect and return a sample of the asteroid back to Earth. To

do that, the spacecraft will carefully tag the surface of

Bennu. The OSIRIS-REx team has selected four possible sample

sites for the mission: Osprey, Kingfisher, Nightingale, and

Sandpiper. The spacecraft has been closely imaging these sites

from different angles to select the best touch-down spot for

OSIRIS-REx. What was originally envisioned as a smooth and easy

touchdown on Bennu’s surface, has become a complex endeavor to

tag a small, crowded space on the asteroid – an area no larger

than a few parking spots, by mid 2020. The OSIRIS-REx team has

already pushed the boundaries of scientific exploration, going

from ground-based radar images all the way to being a few

hundred meters from the asteroid surface, and is now mere months

away from a sample collection attempt.