There was a time when scientists had to wait for an asteroid to fall to Earth before they could study one. But the Japan Aerospace Exploration Agency (JAXA) created a robotic spacecraft capable of touching down on the surface of an asteroid in space and retrieving a sample. This spacecraft, Hayabusa (launched in 2003), and a second like it, Hayabusa2 (launched in 2014, scheduled to land on Earth in December) were both successful.
Now NASA has performed the same feat with a mission called OSIRIS-REx, which was aiming for an asteroid that's about 334 million kilometers from Earth, named Bennu.
“We did it — we tagged the surface of the asteroid. The spacecraft appears to have operated flawlessly,” Dante Lauretta, the principal investigator and a planetary scientist at the University of Arizona in Tucson told Nature. "I hope the world looks at this as a piece of good news — something we can be proud of with all the insanity that’s going on this year."
Asteroids can tell scientists more about how the Solar System formed over 4.5 billion years ago, and the organic material that can be found throughout it. Bennu is thought to have formed between 100 million and one billion years ago.
“This was an incredible feat – and today we’ve advanced both science and engineering and our prospects for future missions to study these mysterious ancient storytellers of the solar system,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “A piece of primordial rock that has witnessed our solar system’s entire history may now be ready to come home for generations of scientific discovery, and we can’t wait to see what comes next.”
OSIRIS-REx launched in 2016 and began to move near Bennu for a closer look in 2018. After that, the scientists realized they would have to create an automated system to navigate massive boulders on its surface. As the spacecraft descended, it snapped images of its target landing region; if there was danger, the landing could be aborted and the spacecraft could hang out and wait for another opportunity.
The approach worked, as seen in the video. OSIRIS-REx was aiming for a crater with a relatively smooth surface about 16 meters wide. The spacecraft descended, stretching its robotic arm, and when it touched down it released nitrogen gas, sending up a cloud of asteroid debris that a device could quickly sample and store.
NASA researchers are hoping to have collected at least 60 grams of material. They will find out in the next week, and if they were successful, OSIRIS-REx will return to Earth. It would be expected to arrive in 2023. If it has less than 40 grams, the scientists will try (one time) for a second sample in January at another site they've selected.
Any sample from Bennu is going to be amazingly useful — a critical addition to the collection of planetary samples that we have on Earth,” Erica Jawin, a planetary scientist at the Smithsonian National Museum of Natural History told Nature. “It probably won’t care too much that we were there and stole some of its rocks.”