Japan's Hayabusa mission returned a small sample of an asteroid known as 25143 Itokawa in 2010; a successor craft, Hayabusa-2, arrived at an asteroid called Ryugu a year ago and is expected to return a sample in 2020.
To give you an idea of just how delicate the New Year's Eve operation will be: OSIRIS-REx will be moving just 4 inches (10 centimeters) per second relative to the asteroid Bennu when it achieves orbit around the rock, mission team members have said. It launched in September 2016 and will spend two years up close and personal with Bennu. To that end, the College of Optical Sciences, which helped design some of OSIRIS-REx's cameras in conjunction with the Lunar and Planetary Laboratory and Steward Observatory, recently received a $20 million endowment. Bennu orbits the Sun on a path fairly similar to Earth's, so the spacecraft had to circle the Sun and catch up to the asteroid. Researchers will provide a more precise description at a scientific meeting on Monday next week in Washington.
The spacecraft will pass Earth in September 2023 and will drop off the capsule (with sample), which will land in the Utah desert using a parachute. "Watching the team celebrate such an incredible milestone brings personal joy to me in so many ways I can't even explain", Heather Enos, the Osiris-Rex deputy principal investigator said of the momentous occasion.
The craft will obtain somewhere between 2 ounces and 4.4 pounds of soil sample from the surface of Bennu using a robotic arm that will blast the surface with a puff of nitrogen gas and collect the pieces that fly off. The craft will never actually touch the asteroid's surface, but instead will hover over the surface close enough to get a sample.
The OSIRIS-REx team will now map the asteroid in extremely fine detail and measure its mass. The primitive asteroids like Bennu resemble what Earth looked like when life began, containing organic molecules, volatiles, and amino acids that may have been the precursors to life on Earth. And Bennu's orbit makes it a "potentially hazardous" asteroid, meaning it's big and could possibly threaten the Earth in the distant future, so scientists hope to further characterize it.
"Besides carbon, Bennu also might have another component important to life: water, which is trapped in the minerals that make up the asteroid". It's because of objects like Bennu that these resources were delivered to Earth during its formation. It is about 1,600 feet (488 meters) wide and most likely broke away from a larger asteroid between Mars and Jupiter a couple of billion years ago. It orbits the sun at roughly the same distance as Earth. And Bennu is believed to be a grouping of rocks held together by gravity rather than a single object.
"During our approach toward Bennu, we have taken observations at much higher resolution than were available from Earth", said OSIRIS-REx project manager Dr. This could also explain how it ended up as a near-Earth asteroid. It will first survey the asteroid's surface for a year, before selecting a safe and "scientifically interesting' location to scoop up some rocks. The exploration of Bennu has just begun, and we have a lifetime of adventure ahead of us".