NASA is planning a short landing on asteroid Bennu

Posted by Ashley Strickland | CNN

After orbiting the near-Earth asteroid Bennu for nearly two years, NASA’s Osiris Rex spacecraft is ready to extend its robotic arm and collect a sample from the asteroid’s surface on Tuesday. This sample will be returned to Earth in 2023.

A van the size of a van must briefly touch its arm at a landing site called Nightingale. The site is showing a few parking spaces. The arm will collect a sample between 2 ounce and 2 kg before retreating to safety.

“It’s NASA’s first historic mission, which is to return a sample from the asteroid, and it’s tough,” Thomas Zurbuchen, assistant director of NASA’s Science Mission Directorate, said at a press conference on Monday.

The site itself is located inside a hole the size of a tennis court and surrounded by rocks the size of the building.

Located more than 200 million miles from Earth, Bennu is a rock-studded asteroid shaped like a rotating summit and the height of the Empire State Building. It is a “pile of rubble” asteroid, which is a collection of rocks linked together by gravity rather than one object.

Mission – meaning assets, spectral interpretation, resource identification, Security-Regolith Explorer – launched in September 2016.

Since its arrival at Bennu, the spacecraft and its cameras have collected data and images and sent them back to help the team learn more about the asteroid formation and map the best possible landing sites for sample collection.

The mission’s main event, called the Touch-and-Go Sampling event, or TAG, is scheduled for October 20 beginning at 5 PM ET.

Bennu has an orbit that brings it close to Earth, which is why it is considered a near-Earth asteroid. One of his futuristic approaches could bring him dangerously close to Earth at some point in the next century; It has one chance in 2,700 to affect our planet.

Samples from Bennu could help scientists understand not only more about asteroids that could affect Earth but also about how planets formed and life began.

“Bennu is almost a rosetta stone, and it tells the history of Earth and our solar system over the past billions of years,” Zurbuchen said. “Bennu has presented a lot of challenges, but the team’s ingenuity has enabled us to get where we are.”

what are you expecting
Instead of so-called “seven minutes of terror” for the attempted landing of the Perseverance craft on Mars next year, the Osiris Rex team expects “4.5 hours of light anxiety,” according to Beth Buck, the mission’s operations program manager at Lockheed Martin Space in Littleton, Colorado.

During this time, the spacecraft will descend from its orbit around the asteroid and eventually get close enough to touch it.

The asteroid and spacecraft are currently located about 207 million miles from Earth, which would result in a delay of about 18.5 minutes in contact.

The team at NASA will share an animation on the mission’s Twitter account that depicts what is happening based on commands already sent to OSIRIS-REx hours before the sample collection sequence.

The live broadcast will also be on the NASA website starting at 5 p.m. ET sharing animations and insights from the mission team while explaining the data they receive.

The spacecraft will perform the entire sequence of approaching the asteroid and collecting the sample independently because live commands from Earth will not be possible.

Touching an asteroid
The event will take about 4.5 hours to unfold and the spacecraft will perform three maneuvers to collect the sample.

The spacecraft will first launch propulsion engines to leave its safe orbit around the asteroid, which is about 2,500 feet from the surface, and travel for four hours before reaching a distance of only 410 feet. After that, the spacecraft will be adjusted to position and speed to continue the descent.

Then, Osiris Rex will slow its descent to target a trajectory that matches the rotation of the asteroid during contact. Its solar panels will be folded into a Y-wing configuration over the spacecraft to protect it.

Finally, the Osiris Rex will land for less than 16 seconds. The spacecraft will launch a compressed nitrogen bottle into the asteroid, using the gas as a way to lift material off the surface of Benno.

The spacecraft collector head will pick up the inverted material. This head, located on the 11-foot robotic sampling arm, is the only part of the spacecraft that will touch Benno. The team compares it to an air filter in an older model car, perfect for collecting fine materials.

There are also small discs, which can collect dust like adhesive pads, on the head if part of the sampling maneuver is not carried out according to plan.

After the accident

A camera on the spacecraft will capture footage of the group event.

The OSIRIS-REx spacecraft will have to detect the risks and delay its mission if there are any obstacles in the way of sample collection. Based on the simulations, the team estimates there is a less than 6% chance that the spacecraft will abort the mission.

By Tuesday evening, the team should be able to confirm whether the landing took place successfully. The spacecraft will return photos on Wednesday, which will provide more details about the sample set and how the spacecraft operates.

The team estimates that they will have a mass measurement of the sample on Saturday. By October 30, NASA will confirm whether the spacecraft has collected enough sample or if it needs another attempt to collect samples in January at another landing site called Osprey.

But if everything goes smoothly, the spacecraft and its precious specimen will begin the long journey to Earth next year and land the sample on Earth in 2023.