NASA's OSIRIS-REx Probe Just Hit Another Milestone

NASA's first asteroid sampling mission is closing in on its target. With just 11 days left until the big rendezvous, the OSIRIS-REx spacecraft is inching its way toward asteroid Bennu and has just 20 million miles to go before reaching the space rock.

Launched on September 8, 2016, the OSIRIS-REx probe has been chasing the 1,640-foot-wide asteroid through space and is about to catch up with Bennu in its orbit around the sun.

Over the course of its two-year mission, the OSIRIS-REx spacecraft has covered a staggering distance, recently reaching a new milestone in its historic journey to the asteroid. According to an announcement made earlier today on social media, the NASA probe has hit the 2-billion-kilometer mark — traveling a total of nearly 1.25 billion miles so far on its way to meet up with Bennu.

To mark the occasion, the OSIRIS-REx team took to Twitter to post a Thanksgiving message, sharing the big news with the world.

"I'm thankful for hydrazine and sunshine," OSIRIS-REx tweeted in the spirit of Thanksgiving.

A couple of hours later, the mission's team shared another tweet acknowledging the many scientists that made this incredible journey possible.

"I am thankful for my team! From asteroid astronomers to graphic designers, I'm lucky to be supported by the most talented, dedicated Earthlings imaginable," tweeted OSIRIS-REx.

As the Inquisitr recently reported, OSIRIS-REx performed its fourth and final asteroid approach maneuver on November 12 and is poised to arrive within 12 miles of Bennu on December 3.

Once the spacecraft reaches its destination, the mission will begin its so-called Preliminary Survey Phase. This entails a series of five flybys of the asteroid's poles and equator — all conducted with the goal of estimating Bennu's mass and creating an accurate model of the space rock's rotation.

According to the OSIRIS-REx website, the spacecraft will come within 4.3 miles of the asteroid during these scheduled flybys. This will ultimately help the team gain more insight on Bennu's surface features "and generate a global shape model at a resolution of 75 centimeters [almost 30 inches]."

Orbit diagram for the OSIRIS-REx spacecraft on its way toward asteroid Bennu.
Orbit diagram for the OSIRIS-REx spacecraft on its way toward asteroid Bennu.

These procedures are of great importance in mapping potential sample sites and determining where on the asteroid the OSIRIS-REx probe will swoop down in July 2020 to grab at least two ounces of regolith (dust and broken rock).

While the big event is nearly two years away, the spacecraft has already prepared for this important task by practicing the moves that will allow it to reach out to Bennu and snag the precious samples from the asteroid's surface. On November 14, OSIRIS-REx stretched out its Touch-and-Go Sample Acquisition Mechanism (TAGSAM) — a robotic arm designed to extend down to Bennu and snatch the asteroid samples.

Although the procedure was extensively rehearsed back on Earth, this was the first time that OSIRIS-REx deployed the TAGSAM in space, NASA reported last week. The instrument will allow the probe to make a brief, five-second contact with the asteroid's surface and blast Bennu with nitrogen gas to stir up loose dirt and rock bits for sampling.

The spacecraft carries "enough nitrogen to allow three sampling attempts," notes the OSIRIS-REx website, and has the capacity to collect up to 70 ounces of asteroid material.


"The TAGSAM exercise is an important milestone, as the prime objective of the OSIRIS-REx mission is to return a sample of Bennu to Earth," Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson, said in a statement. "This successful test shows that, when the time comes, TAGSAM is ready to reach out and tag the asteroid."

During the procedure, the probe tested the robotic arm's full range of motion, flexing all of the TAGSAM's "joints" for the first time since OSIRIS-REx left our planet.

"The team is very pleased that TAGSAM has been released, deployed, and is operating as commanded through its full range of motion," said Rich Burns, OSIRIS-REx project manager at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "It has been restrained for over two years since launch, so it is gratifying to see it out of its shackles and performing well."

The OSIRIS-REx spacecraft is slated to leave Bennu on March 2021. If everything goes as planned, the return trip to Earth will last for another 2.5 years, culminating with the parachute delivery of the asteroid samples on September 24, 2023.