Arizona-Led Asteroid Mission Swings Around Earth

James Marshall
September 22, 2017

Today, NASA's asteroid sample return mission, OSIRIS-REx, will whizz round the Earth and use our planet's gravity like a slingshot to fling it on direct course towards asteroid Bennu. KNAU's Melissa Sevigny reports.

Launched a year ago, Osiris-Rex was on track to pass within about 11,000 miles (17,700 kilometers) of the home planet Friday afternoon - above Antarctica.

The slingshot maneuver, called an Earth gravity assist, lets the spacecraft gain speed without carrying extra fuel. Benny is carbon-rich (where the b comes from in its designation as a b-type asteroid) and its chemical make-up reflects the type of material that was around in the early Solar System.

The mission is led by the University of Arizona.

A Nasa spacecraft is about to do a near miss of Earth
NASA's asteroid hunting OSIRIS-REx spacecraft to make a close flyby of Earth at 30758 kph

The OSIRIS-Rex science team is encouraging Earthlings to submit their ground-based observations taken during the flyby Friday.

"The opportunity to capture images of the OSIRIS-REx spacecraft as it approaches Earth provides a unique challenge for observers to hone their skills during this historic flyby", OSIRIS-REx principal investigator Dante Lauretta said. It - or rather someone's human mind - accomplished this by factoring in the six degree difference between the earth's orbit around the sun and the asteroid's.

NASA expected to be out of contact with Osiris-Rex for about an hour during the flyby. It also has the potential to threaten Earth, but not for another 160 years. Analysts will look for evidence of debris or moons in the asteroid's vicinity before OSIRIS-REx's arrival. "That's when we'll actually do a close approach over the north pole of the asteroid with an imaging campaign, and then do a couple of maneuvers and repeat that sequence multiple times". It will hover like a hummingbird as a mechanical arm briefly rests on the surface and sucks in samples stirred up by nitrogen gas thrusters. The mission is the first asteroid sample return attempt mounted by NASA, and the second worldwide after Japan's Hayabusa mission brought back microscopic specimens from asteroid Itokawa in 2010. Following its initial analysis, a sample site will be selected and the spacecraft will move into position so that it can collect a sample of Bennu's surface material. Scientists believe Bennu may have seeded the Earth with organic compounds that made life possible.

"This is really giving us a taste of what we're going to experience next year, and I think it's the start of building the excitement for our asteroid encounter", Lauretta said of Friday's flyby of Earth.

Other reports by Click Lancashire

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