NASA Launching Probe to Asteroid Bennu: Watch Live

An artist concept of the OSIRIS-REx spacecraft. Image credit: NASA / Goddard.

An artist concept of the OSIRIS-REx spacecraft. Image credit: NASA / Goddard.

NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-Rex) is scheduled to blast off from Cape Canaveral today, September 8, 2016, on a mission to orbit, map and collect samples from a near-Earth asteroid called Bennu.

Liftoff is scheduled at 7:05 p.m. EDT (4:05 p.m. PDT, 11:05 p.m. GMT, 1:05 a.m. CET Sept. 9, 4:35 a.m. IST Sept. 9, 9:05 a.m. AEST Sept. 9).

The weather forecast for launch atop a United Launch Alliance Atlas V rocket is 80% ‘go.’

You can watch live coverage of the launch on NASA TV or in the livestream below.

The asteroid (101955) Bennu was discovered in 1999 by the NASA-funded LINEAR asteroid survey.

This celestial body is about 1,600 feet (492 m) in diameter and has a mass of 60 million tons.

“Think of it as a small mountain in space. It is a near-Earth asteroid that makes occasional close approaches to our planet,” said Prof. Dante Lauretta of the University of Arizona, Principal Investigator on the OSIRIS-REx mission.

Bennu is interesting due to its size and composition, and it is accessible to be sampled. It is a primitive and carbon-rich asteroid. Primitive asteroids contain material that has not changed significantly since they formed over 4.5 billion years ago.

The analysis of any organic material found on Bennu will give scientists an inventory of the materials present at the beginning of our Solar System that may have had a role in the origin of life on Earth, and potentially elsewhere.

Prof. Lauretta said: “mapping and sampling the space rock can potentially hold answers to the most fundamental questions human beings ask, like: Where do we come from?”

The OSIRIS-REx mission is a seven-year journey from launch to Earth return.

The spacecraft will spend the first two years of the mission cruising to asteroid Bennu, arriving in August 2018.

Its five specialized instruments will be used to map the asteroid’s surface, identify the minerals and chemicals that may be on the surface, and select the sample site.

“The primary objective of the mission is to bring back 60 grams of pristine carbon-rich material from the surface of Bennu,” Prof. Lauretta said.

In July 2020, OSIRIS-REx will briefly touch the surface of the asteroid to collect loose rocks and dust using the Touch-and-Go Sample Acquisition Mechanism (TAGSAM) and store the material in a sample return capsule.

The spacecraft will depart the asteroid in March 2021, when the departure window opens, and travel for two-and-a-half years on a trajectory for Earth return in September 2023.

As OSIRIS-REx approaches the Earth, the sample return capsule will eject from the spacecraft and land with the help of parachutes at the Utah Test and Training Range, southwest of Salt Lake City. The canister will be retrieved and transported to NASA’s Johnson Space Center in Houston for analysis.

The main OSIRIS-REx spacecraft will remain in orbit around the Sun after the sample return and Earth flyby.

NASA scientists will be keen to learn about Bennu for another reason, too.

Bennu orbits the Sun between Venus and Mars so it crosses Earth’s orbit frequently and comes close to Earth every six years.

In 2010, a team of researchers determined that Bennu could have a relatively high probability of impacting Earth between the years 2169 and 2199.

“The OSIRIS-REx mission will give us data to help more precisely predict Bennu’s orbit and, in general, devise strategies to mitigate possible impacts between Earth and other asteroids,” said Prof. Beth Ellen Clark of Ithaca College, the mission asteroid scientist for OSIRIS-Rex.

Predicting a small asteroid like Bennu’s exact course is somewhat tricky, due to the Yarkovsky effect.

The dark asteroid absorbs sunlight and then gives it off as heat, which serves as a gentle thruster that gradually shifts its path.

“We’ll get accurate measurements of the Yarkovsky effect on Bennu by precisely tracking OSIRIS-REx as it orbits the asteroid,” said Dr. Edward Beshore of the University of Arizona, Deputy Principal Investigator for OSIRIS-Rex.