next week will briefly touch a large asteroid and grab a few rocks and dust from its surface to return them to Earth for study. The event is the first important one for NASA and a potential benefit to science, space exploration and our understanding of the solar system.
The collection of samples of the asteroid 101955 Bennu Touch-and-Go (TAG) is going to be destroyed on Tuesday, October 20, at about 15:12 Pacific time. NASA will broadcast the TAG maneuver live on NASA TV and on the agency’s website starting at 14:00 on Tuesday. Here’s everything else you need to know about Osiris-Rex, Benna, and how NASA is planning a pocket asteroid theft.
When did the mission begin?
Osiris-Rex as a concept has existed since at least 2004, when a group of astronomers first proposed this idea to NASA. After more than a decade of spacecraft development, on an Atlas V rocket helicopter from the United Launch Alliance, a joint venture between Lockheed Martin and Boeing. For the next 26 months, the spacecraft flew to Benn, officially arriving on December 3, 2018.
Since then, the mission team has spent nearly two years revolving around a diamond-shaped space rock, surveying and mapping its surface to select the best sampling site. Rehearsals have begun in recent months on the eve of a future attempt to collect samples, and now the team says it is ready to play in the TAG with Benn.
Bennu is a so-called asteroid “rubble heap”, ie it was formed in the deep cosmic past, when gravity slowly forced the remnants of an ancient collision. The result is a body in the shape of something like a spinning wheel with a diameter of about a third of a mile (500 meters) and a surface strewn with large rocks and boulders.
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 in space exploration.
The asteroid has another characteristic that makes it especially interesting for scientists and people in general – it has a chance to affect the Earth in the distant future. In the list of risks of influence of NASA Bennu takes the 2nd place. Current data shows dozens of potential consequences in the last quarter of the 22nd century, although they all have only a one-minute chance of actually materializing.
How will TAG work?
For those who have ever played with robots or perhaps even participated in robotics competitions, the mission of Osiris-Rex would seem to be the ultimate pinnacle of the young robotist’s dreams. The touch sampling procedure is a complex task with high rates, which is adjusted to a key climax for years. If it succeeds, it will play a role in history and our future in space.
The main plan is that Osiris-Rex will touch Benn on the rocky terrain. The spacecraft the size of a van will have to match the boulders the size of a building around the landing area to touch a relatively clean space the size of just a few parking spaces. However, the sample work for sampling will be the only part of Osiris-Rex that actually comes to the surface. One of the three pressurized nitrogen cylinders will fire to mix the sample of dust and fine rocks, which can then be captured in the collector head for safe storage and return to Earth.
The descent to the surface of Benn will take about four hours, about as long as it takes the asteroid to make one full revolution. After such a slow approach, the actual TAG sampling procedure is extremely less than 16 seconds.
Preparations for the TAG did not go as planned. Initially, the mission organizers hoped that there would be many potential landing sites on Benn’s surface, covered mostly with small materials comparable to sand or gravel. It turns out that the surface of Benn is extremely strong, without real friendly places to land.
After spending most of the last two years overestimating the mission, the team decided to try to “push the needle” through the boulder-filled landscape of Nightingale and several other exemplary places. Still, the surface will be too rocky to get a good sample. If this is the case, the team may try again on another site. Osiris-Rex is equipped with three canisters of nitrogen for fire and surface destruction, which means that the team receives up to three attempts to collect a sample.
Immediately after collecting the sample, Osiris-Rex will release the engine to retreat from Benn. The spacecraft will continue to hover over Benn until the end of 2020, before finally making a take-off maneuver next year and embarking on a two-year journey back to Earth.
On September 24, 2023, Osiris-Rex plans to release his exemplary return capsule, which will land in the Utah desert and be removed for research.
Hasn’t this been done before?
So. The Japanese spacecraft Hayabusa successfully returned the tiny grains of asteroid 25143 Itokawa to Earth in 2010. His successor “Hayabusa-2” successfully returnedand then took out some of the fragments. This specimen is currently returning to Earth.
How can I watch?
Watch NASA’s live broadcast, which starts on Tuesday at 14:00 Pacific time. You can also follow Osiris-Rex’s Twitter feed to get the latest updates.