The touch-and-go (TAG) sample collection of the asteroid 101955 Bennu is set to crash on Tuesday, October 20 at. 15:12 PT. NASA broadcasts the TAG maneuver live on NASA TV and the agency’s website, starting at 14 PT Tuesday. Here’s everything else you need to know about Osiris-Rex, Bennu, and how NASA plans to pickpocket an asteroid.
When did the mission begin?
Osiris-Rex as a concept has been around since at least 2004, when a team of astronomers first proposed the idea to NASA. After more than a decade of development, the spacecrafton top of an Atlas V rocket from the United Launch Alliance, a joint venture between Lockheed Martin and Boeing. The spacecraft spent the next 26 months driving to Bennu and officially arrived on December 3, 2018.
Since then, the mission team has spent nearly two years in orbit around the diamond-shaped space rock, mapping and mapping the surface to select the best sampling site. In recent months, trials have begun ahead of the upcoming trial fundraising trial, and now the team says it is ready to play TAG with Bennu.
Bennu is what is called a “rubble” asteroid, meaning that it was formed in the deep cosmic past, when gravity slowly forced together remnants of an ancient collision. The result is a body shaped like a spinning top about a third of a mile (500 meters) in diameter and a surface strewn with large rocks and stones.
Bennu is believed to be 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, may also be worth extracting at some point in the future for use on earth or for space exploration.
The asteroid has another property that makes it particularly interesting to scientists and humans in general – it has a chance to affect the Earth in the distant future. On NASA’s list of impact risks, Bennu is ranked No. 2. Current data shows dozens of potential impacts in the last quarter of the 22nd century, although all have only a minute to actually be implemented.
How does TAG work?
For anyone who has ever doubled with robots or perhaps even participated in a robot competition, the Osiris-Rex mission seems to be the ultimate culmination of a young robotist’s dreams. The touch-and-go sampling procedure is a complex, high-effort task that has built up to an important climactic moment for years. If successful, it will play a role in history and our future in space.
The basic plan is that Osiris-Rex will touch Bennu on a rock. The van-sized spacecraft will have to negotiate building-sized boulders around the landing area to touch a relatively clear space that is only as large as a few parking spaces. However, a robotic sampling arm will be the only part of the Osiris-Rex that actually settles to the surface. One of three pressurized nitrogen containers will fire to touch a sample of dust and small rocks, which can then be trapped in the arm’s collection head for safe storage and return to the ground.
The descent to the surface of Bennu takes about four hours, about the time it takes for the asteroid to make a full revolution. Following this slow approach, the current TAG sample collection procedure lasts remarkably less than 16 seconds.
Preparations for the TAG have not gone exactly as planned. Mission organizers initially hoped that the surface of Bennu would have plenty of potential landing sites, primarily covered with fine materials comparable to sand or gravel. It turns out that the surface of the Bennu is extremely robust with no real inviting landing spots.
After spending much of the last two years reassessing the mission, the team decided to try to “thread the needle” through the rocky landscape at Nightingale and a few other backup test sites. It is still possible that the surface will turn out to be too rocky to get a good sample. If this turns out to be the case, the team may choose to try again at another location. Osiris-Rex is equipped with three nitrogen containers to fire and disturb the surface, which means that the team gets up to three attempts to nip a sample.
Immediately after collecting his sample, Osiris-Rex will shoot his thrusters to return from Bennu. The spacecraft will continue to hang around Bennu for the rest of 2020, before finally performing a departure maneuver next year and embarking on a two-year journey back to Earth.
On September 24, 2023, Osiris-Rex is scheduled to jettison its sample return capsule, which lands in the Utah Desert and is recovered for investigation.
Has this not been done before?
Yes. Japan’s Hayabusa spacecraft successfully returned small grains of the asteroid 25143 Itokawa to Earth in 2010. Its successor, Hayabusa-2, successfullyand then retrieved some of the shrapnel. This sample is currently on its way back to Earth.
How can I see?
Follow NASA’s livestream, which begins Tuesday at 2 p.m. PT. You can also follow the Osiris-Rex Twitter feed to get the latest updates.