SoylentNews

Open4D [soylentnews.org] writes:

EurekAlert reports: "NASA to map the surface of an asteroid [eurekalert.org]"

NASA's OSIRIS-REx spacecraft will launch September 2016 and travel to a near-Earth asteroid known as Bennu to harvest a sample of surface material and return it to Earth for study. The science team will be looking for something special. Ideally, the sample will come from a region in which the building blocks of life may be found.

The Daily Mail points out [dailymail.co.uk]:

Bennu crosses Earth's orbit once every six years and is set to pass between the moon and our planet in 2135.
Scientists are worried the 500-metre wide asteroid's orbit could be tweaked by Earth's gravity as it passes by, causing it to smash into our planet later in the century.
...
'We estimate the chance of impact at about one in 2,700 between 2175 and 2196,' [Prof. Lauretta] said.

It seems this (paywalled) Sunday Times article [thetimes.co.uk] might be the original source for the quotes from Prof. Lauretta. Here are some excerpts from the article:

“Bennu is a carbonaceous asteroid, an ancient relic from the early solar system that is filled with organic molecules,” said Lauretta.

“Asteroids like Bennu may have seeded the early Earth with this material, contributing to the primordial soup from which life emerged.”
...
For scientists, the chance of obtaining chunks of a carbonaceous asteroid is exciting. For the rest of us, however, Osiris-Rex’s most important task may be the measurements it makes of a bizarre and newly discovered force that can send asteroids careering around the solar system and potentially towards Earth.

“The Yarkovsky effect is the force that acts on an asteroid when it absorbs sunlight and then radiates it back into space as heat. It acts like a small thruster, constantly changing its course,” said Lauretta. “Bennu’s position has shifted 160km [100 miles] since 1999.”

It is these forces that make Bennu’s trajectory so hard to predict after 2135’s near-miss. It is expected to pass Earth at a distance of about 180,000 miles, well inside the moon’s orbit and close enough to alter the asteroid’s path so it may hit our planet on a future orbit.

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