Asteroids are rocky bodies that orbit the sun, mostly between Mars and Jupiter. They are the remnants of the early solar system when planets were forming from dust and gas. By studying asteroids, we can learn more about how our solar system and life on Earth came to be. We can also assess the potential risks and opportunities that asteroids pose to our planet, such as asteroid impacts or asteroid mining.
But studying asteroids is not easy. They are very far away, very small, and very diverse. That is why NASA launched the Osiris-Rex mission in 2016, a bold and ambitious project to collect and return material from an asteroid for the first time. The mission targeted Bennu, a near-Earth asteroid that is about 500 meters wide and has a 1 in 2,700 chance of hitting Earth in the late 22nd century.
The Osiris-Rex mission has been a remarkable success, achieving several scientific and engineering milestones. It has also faced many challenges and surprises along the way. In this article, we will explore how the mission collected and returned material from Bennu, what it hopes to learn from it, and what it means for the future of asteroid exploration.
Collecting Dust and Rocks from Bennu
The Osiris-Rex spacecraft reached Bennu in December 2018 after a two-year journey from Earth. It spent almost two years orbiting and mapping the asteroid, looking for a suitable landing site. The spacecraft had to deal with rugged and hazardous terrain, full of boulders and craters. It also had to cope with Bennu’s weak gravity, which made it hard to maintain a stable orbit.
The spacecraft finally selected a site called Nightingale, which was only 16 meters wide and surrounded by large rocks. On October 20, 2020, the spacecraft performed a touch-and-go maneuver to collect dust and rocks from Nightingale. It extended a robotic arm with a circular device called TAGSAM (Touch-And-Go Sample Acquisition Mechanism), which blew nitrogen gas onto the surface and captured the material that was lifted up.
The manoeuvre lasted only six seconds, but it was enough to collect more than 250 grams of material, exceeding the mission’s minimum requirement of 60 grams. The spacecraft then stored the sample in a capsule and secured it for return. You can see some images or videos from the mission here.
Analyzing the Material from Bennu
The material collected by Osiris-Rex is precious for science, as it represents a pristine sample of an ancient asteroid that has not been altered by weathering or contamination. By analyzing the material, scientists hope to answer some of the fundamental questions about the origin and evolution of the solar system, as well as the potential threats and benefits that asteroids pose to Earth.
One of the main questions that scientists want to address is how asteroids like Bennu formed and changed over time. Bennu is classified as a carbonaceous asteroid, which means it contains organic molecules that may have played a role in the origin of life on Earth. By studying the composition, age, history, and origin of Bennu’s material, scientists can learn more about how these molecules were delivered to Earth by asteroids and comets in the past.
Another question that scientists want to address is how asteroids like Bennu interact with other celestial bodies, such as planets, moons, and other asteroids. Bennu is influenced by various forces, such as gravity, radiation, and collisions, which affect its orbit and shape. By studying how Bennu’s material responds to these forces, scientists can improve their models and predictions of how asteroids move and evolve in space.
Delivering the Material to Earth
The Osiris-Rex mission is not over yet. The spacecraft still has one more task to complete: delivering the material to Earth. The spacecraft will leave Bennu’s orbit on May 10, 2021, and begin its journey back home. It will travel for about two and a half years, covering more than 2 billion kilometers.
On September 24, 2023, the spacecraft will approach Earth and release the capsule containing the material. The capsule will enter Earth’s atmosphere at a speed of about 12 kilometers per second, protected by a heat shield. It will then deploy a parachute and land in the Utah desert, where it will be recovered by a team of scientists.
The material will then be distributed to various laboratories around the world for analysis. Some of it will be stored for future generations of researchers who may have more advanced techniques and instruments. The spacecraft will also continue to observe Bennu until 2025, monitoring its orbit and activity.
Advancing Asteroid Exploration
The Osiris-Rex mission is an unprecedented achievement for science and technology. It is the first NASA mission to collect material from an asteroid, and the largest sample returned from space since the Apollo moon missions. It is also one of the longest and most complex missions ever flown, requiring precision, coordination, and innovation.
The mission has also opened new horizons for asteroid exploration, paving the way for more missions that will visit and study these fascinating and diverse worlds. For example, NASA’s Lucy mission will launch in 2021 and explore six asteroids that orbit the sun along with Jupiter. NASA’s Psyche mission will launch in 2022 and explore a metallic asteroid that may be the core of a failed planet. Japan’s Hayabusa2 mission, which also collected material from an asteroid in 2019, will launch a new mission in 2024 to visit two more asteroids.
The Osiris-Rex mission is a testament to the human curiosity and creativity that drives us to explore the unknown and learn more about our place in the universe. The mission’s findings will not only improve our understanding of asteroids and their influence on the solar system, but also inspire future generations of scientists and explorers to pursue new challenges and discoveries.
