In the vast expanse of our solar system, asteroids have always fascinated astronomers and space enthusiasts alike. Among the multitude of celestial bodies, Bennu holds a special place as one of the most dangerous asteroids known to NASA. However, this enigmatic space rock has recently become the subject of intense scrutiny, thanks to the collaboration between renowned planetary science expert Dante Lauretta from the University of Arizona and astrophysicist Brian May. Together, they have produced “Bennu 3-D: Anatomy of an Asteroid,” a groundbreaking atlas that sheds light on the secrets of this ancient space traveler, featuring data and images from NASA’s OSIRIS-REx mission.
The OSIRIS-REx Mission
The OSIRIS-REx mission stands for Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer. It marks NASA’s first attempt to retrieve a sample from an ancient asteroid and bring it back to Earth. Launched in September 2016, this ambitious mission aimed to unravel the mysteries of Bennu, a celestial object that could potentially pose a threat to our planet in the future.
About Bennu
Bennu is located approximately 200 million miles away from Earth, making it a near-Earth asteroid (NEA). It was first discovered by a team from the NASA-funded Lincoln Near-Earth Asteroid Research team in 1999. The asteroid belongs to the B-type category, indicating that it contains significant amounts of carbon and various other minerals.
One of the most intriguing aspects of Bennu is its peculiar shape. The asteroid’s shape resembles a spinning top, with a diameter of around 500 meters (1640 feet) and a mass of about 79 billion kilograms (174 billion pounds). However, not all of its interior is solid material. Scientists estimate that approximately 20-40 percent of Bennu’s interior is empty space, making it akin to a porous rubble pile.
Bennu’s Origins
Studying Bennu can provide valuable insights into the early history of our solar system. Scientists believe that the asteroid was formed within the first 10 million years of the solar system’s creation, making it approximately 4.5 billion years old. This ancient space traveler is thought to have originated in the Main Asteroid Belt, located between the orbits of Mars and Jupiter.
The journey of Bennu from the Main Asteroid Belt to its current orbit near Earth has been an intricate interplay of gravitational interactions with other celestial objects. As other astronomical bodies tugged at Bennu and it released absorbed sunlight, the slight push imparted on the asteroid nudged it closer to Earth over time.
The Hazardous Nature of Bennu
NASA classifies Bennu as a Potentially Hazardous Asteroid (PHA), indicating that its trajectory could bring it perilously close to Earth in the future. However, the probability of a significant impact in the foreseeable future remains relatively low. Understanding the asteroid’s composition, structure, and trajectory is crucial in devising potential strategies to mitigate potential risks posed by PHAs in the long run.
OSIRIS-REx’s Historic Sampling Mission
The primary objective of NASA’s OSIRIS-REx mission was to collect a sample from the surface of Bennu and return it to Earth. This delicate maneuver required precise planning and execution to ensure a successful retrieval. The spacecraft, equipped with specialized instruments and a robotic arm called TAGSAM (Touch-And-Go Sample Acquisition Mechanism), carefully approached the asteroid’s surface.
After careful mapping and selection of a suitable site for sampling, OSIRIS-REx briefly touched the asteroid’s surface to collect pristine regolith (loose surface material). The spacecraft then successfully stored the sample inside a return capsule, which is set to make its journey back to Earth, carrying the valuable cargo of ancient asteroid material.
