Due to their rich composition, asteroids are a key
to unlocking facts about our sun and planets’ history.
There isn’t a huge difference between the makeup
of a primitive asteroid today versus when they were
formed almost 4.5 billion years ago, therefore they
may hold answers to long standing scientific and
philosophical questions about where life on this planet originated.
The carbon-rich asteroid chosen to be the focus
of this mission is named Bennu. Bennu is a B-type asteroid with a diameter of around 500 meters. When
it orbits, it comes very close to Earth every six years –
about 0.002 AU (astronomical units) away. There are
several reasons Bennu was picked – its distance from
Earth, its size, and its composition are a few of them.
But there is another much more dramatic reason to
study this asteroid - because of how close it orbits
near Earth, there is a high probability it could hit the
planet sometime in the late 22nd century.
OSIRIS-REx will spend a year surveying Bennu before collecting a sample to
return to Earth for analysis. Credit: NASA/Goddard/University of Arizona
Asteroids contain an abundance of natural resources, including water, organics, and precious metals that could be critical supporting components for
future manned and robotic spacecraft traveling the
solar system. Also, quite importantly, the chemical
and physical makeup of Bennu will be essential information needed in the case of an imminent future
impact with Earth and scientists would need to devise a plan to extinguish the threat.
The primary science objectives for OSIRIS-REx
include the following:
• Return and analyze a sample of Bennu’s surface
• Map the asteroid
• Document the sample site
• Measure the orbit deviation caused by
non-gravitational forces (the Yarkovsky
effect)
• Compare observations at the asteroid
to ground-based observations
The spacecraft will be packed atop an Atlas V 411
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