CAPE CANAVERAL, Fla. (AP) — The NASA spacecraft, orbiting an ancient asteroid hundreds of millions of miles away for nearly two years, is going down this week to a dangerous rock-filled surface to catch a handful of debris.
The drama is an achievement only in Japan so far, with the U.S. making its first rift in collecting asteroid samples to return to Earth on Tuesday.
Filled with names inspired by Egyptian mythology, the Osiris-Rex mission is working to bring back this largest globally transported asteroid Bennu beyond the moon, worth at least 60 grams (2 ounces).
The van-sized spacecraft is aiming at the relatively flat center of a tennis court-sized crater named Nightingale, which is similar to a few parking spots here on Earth. You will see a rock as big as a building in the target touchdown area.
“So the next time you park your car in front of your house or in front of a coffee shop and get inside, think about the problem of moving Osiris-Rex from 200 million miles away to one of these places.” Mike Moreau, NASA’s Deputy Project Manager, said.
After dropping off the 0.5-mile-high (0.75 km-high) orbit around Bennu, the spacecraft takes 4 hours to descend just above the surface.
Then, Osiris-Rex’s 3.4-meter (11-foot) arm stretches out to reach Bennu, and the action begins. The contact should last for 5-10 seconds, and it should be long enough to exhale compressed nitrogen gas and soak up warped dirt and gravel. The pre-programmed spacecraft operates autonomously during an unprecedented touch-and-go maneuver. The ground controller of spacecraft maker Lockheed Martin near Denver is unable to intervene due to an 18-minute radio delay on one way.
If the first try doesn’t work, Osiris-Rex may try again. The collected samples will not reach Earth until 2023.
Although NASA has recovered comet dust and solar wind particles, it has never attempted to sample one of the nearly 1 million known asteroids hiding in our solar system so far. Meanwhile, Japan expects to get a sample of up to milligrams from the asteroid Ryugu in December 10 years after it recovered the spot from the asteroid Itokawa.
Bennu is an asteroid picker paradise.
Bigger, taller, rounder, and more carbon-rich than the Empire State Building in New York, this rock was around 4.5 billion years ago when our solar system was formed. Scientists believe it is a time capsule full of clean building blocks that can help explain how life formed on Earth and elsewhere.
“It’s all about understanding our origins,” said Dante Lauretta, chief scientist at the University of Arizona.
There are also selfish reasons to get to know Bennu better.
The solar orbiting asteroid, which shakes the Earth every six years, could be aimed at us later in the next century. NASA has set the probability of impact to 1-in-2,700. The more scientists learn about potentially menacing asteroids like Bennu, the safer the Earth will be.
Scientists envisioned Bennu’s stretch of sand when Osiris-Rex caused an explosion in 2016 on more than $800 million missions. Therefore, the spacecraft is designed to take in small pebbles less than 2 centimeters in diameter.
Scientists were amazed by the discovery of massive rocks and blunt gravel when the spacecraft arrived in 2018. And I’ve witnessed gravel shooting bullets off an asteroid and occasionally popping back out of the table tennis space game.
With so much rough terrain, the engineers tried to hit a narrower spot than originally expected. The main target, the Nightingale Crater, appears to have the most microscopic particles, but is still rocky, including a rock named Mount Doom.
Then COVID-19 occurred.
The team fell behind and had a second and final touch-and-go dress rehearsal for the spaceship by August. This led to an increase in sample collection to October.
“It’s difficult to return samples,” said Thomas Zurbuchen, director of science missions at NASA. “The COVID makes it even more difficult.”
Osiris-Rex has 3 bottles of nitrogen gas. That means you can no longer touch down three times.
When the spacecraft faces unexpected dangers, such as a large rock that can overturn, it will automatically retreat. And while it is possible that it falls safely, it may not be able to collect enough debris.
In both cases, the spacecraft returns to orbit around Bennu and tries again in January at another location.
Finally, on the first try, Lauretta was worried, nervous and excited, “I’m sure we’ve done everything possible to ensure safe sampling.”
The Associated Press Health and Science Department is supported by the Department of Science Education at Howard Hughes Medical Institute. AP is solely responsible for all content.