NASA 's Osiris-Rex spacecraft will briefly land on a large asteroid on Tuesday and collect some rocks and dust from its surface to return to Earth for study.
This marks a major first for NASA and a potential benefit for science, space exploration, and our understanding of the solar system. Lockheed Martin Space will be live streaming the daring mission on Tuesday, and we've got everything you need to know about the mission and how to watch it.
The sample collection from asteroid 101955 Bennu is expected to occur on Tuesday, October 20 at approximately 3:12 p.m. PT. NASA will broadcast the sample collection live on NASA Television and the agency's website beginning at 2 p.m. PT on Tuesday.
When did the mission begin?
Osiris-Rex has been a concept since 2004, when a team of astronomers first proposed the idea to NASA. After more than a decade of development, the spacecraft launched from Cape Canaveral, Florida, on September 8, 2016, aboard an rocket from United Launch Alliance, a joint venture between Lockheed Martin and Boeing. The spacecraft spent the next 26 months traveling to Bennu, officially arriving on December 3, 2018.
Since then, Osiris-Rex has spent nearly two years orbiting the diamond-shaped space rock, studying and mapping its surface to choose the best sampling spot. In recent months, rehearsals have begun ahead of the upcoming sample collection attempt, and now the team says it's ready to take the big step.
Why was the asteroid Bennu chosen?
Bennu formed in the past when gravity slowly forced together the remnants of an ancient collision. The result is a rotating peak-like body about 500 meters in diameter and a surface covered with large rocks and boulders.
Bennu is considered a window into the solar system's past: a pristine, carbon-rich body that carries the building blocks of both planets and life. Some of these resources, such as water and metals, could also be mined at some point in the future for use on Earth or in space exploration.
The asteroid has another feature that makes it particularly important for scientists and people in general – it has the potential to impact Earth in the distant future. On NASA's list of the most dangerous objects to collide with Earth, Bennu ranks at number 2. Current data shows dozens of possible collisions in the last quarter of the 22nd century, although all of them have a low probability of actually happening.
How will sample collection work?
For anyone involved in robotics or who has participated in a robotics competition, the Osiris-Rex mission seems like the ultimate culmination of a young robotics enthusiast's dreams. The touch-and-go sampling process is a complex, high-level process that has been years in the making. If it succeeds, it will play a role in the history and future of our space exploration.
The basic plan is for Osiris-Rex to land on Bennu at a rocky site called Nightingale. The truck-sized spacecraft will have to navigate through building-sized boulders to land in a relatively accessible area about the size of a few parking spaces. However, a robotic sampling arm will be the only part of Osiris-Rex that will reach the surface. One of three pressurized nitrogen tanks will be fired to create a cloud of dust and small rocks that can then be captured by the arm’s collection head for safekeeping and return to Earth.
The descent to Bennu's surface will take about four hours, the time it takes for the asteroid to make one complete rotation. After this slow approach, the actual sample collection process takes less than 16 seconds.
Preparations for the landing didn't go exactly as planned. Mission organizers initially hoped that Bennu's surface would have many potential landing sites, mostly covered in materials comparable to sand or gravel. It turns out that Bennu's surface is extremely rugged with no truly hospitable landing sites.
What will happen after the sample is taken?
Immediately after collecting the sample, Osiris-Rex will fire its thrusters to move away from Bennu. The spacecraft will continue to orbit Bennu for the rest of 2020 before finally performing a departure maneuver sometime next year to begin a two-year journey back to Earth.
On September 24, 2023, Osiris-Rex is scheduled to launch the mission's sample capsule, which will land in the Utah desert and be retrieved for study.
Has anything similar happened before?
Yes. Japan's Hayabusa spacecraft successfully brought tiny grains of asteroid 25143 Itokawa to Earth in 2010. Its successor, Hayabusa-2, fired a special copper ball at the large asteroid Ryugu in 2019 and subsequently retrieved samples of its surface. That sample is now on its way to Earth.
How can I track the shipment?
Follow NASA's live stream, which begins Tuesday at 2 p.m. PT. You can also follow Osiris-Rex's Twitter for the latest updates.
