Asteroid-bound spacecraft zips by Earth for gravity boost

An unmanned NASA spacecraft traveling to a distant asteroid veered toward Earth for a gravitational slingshot maneuver that will better aim it toward the Sun-orbiting space rock, Bennu, the US space agency said.

The gravity-boost took place about halfway through the two-year journey of the spacecraft, known as OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer).

“The preliminary results are in, and my #EarthGravityAssist was succesful!” said the NASA Twitter account for OSIRIS-REx, about an hour after it made its closest approach to Earth at 12:52 pm (1652 GMT).

The mission launched last year from Cape Canaveral, Florida. Its goal is to collect a sample from Bennu in 2018, and return it to Earth for further study in 2023. Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson, described the gravity-assist as “a clever way to move the spacecraft onto Bennu’s orbital plane using Earth’s own gravity instead of expending fuel.”

The spacecraft zipped over Antarctica at a distance of 11,000 miles (17,000 kilometers), using Earth’s gravity to shift its trajectory so it can eventually meet up with Bennu.

Bennu is a primitive, carbon-rich asteroid, the kind of cosmic body that may have delivered life-giving materials to Earth billions of …read more