CAPE CANAVERAL, Fla. (AP) – After nearly two years orbiting an ancient asteroid hundreds of millions of miles away, a NASA spacecraft this week will attempt to descend on the treacherous, boulder-filled surface and add a handful of debris snap.
The drama unfolds on Tuesday when the US collects asteroid samples for the first time to return to Earth, an feat that only Japan has so far achieved.
The Osiris Rex mission is full of names inspired by Egyptian mythology and seeks to bring back the asteroid Bennu, the largest otherworldly transport from beyond the moon, worth at least 60 grams.
The van-sized spaceship targets the relatively flat center of a crater the size of a tennis court called Nightingale ̵
“So the next time you park your car in front of your house or a coffee shop and go inside, think from one perspective about the challenge of navigating Osiris-Rex to one of these places from 200 million miles away.” said NASA deputy project manager Mike Moreau.
Once it falls out of its 0.75-kilometer orbit around Bennu, it will intentionally take the spaceship four hours to make it all the way to the top, to just above the surface.
Then everything turns when Osiris-Rex’s 3.4 meter long arm reaches for Bennu. Contact should last five to 10 seconds, just long enough to expel pressurized nitrogen gas and soak up the churned up dirt and gravel. The pre-programmed spaceship works autonomously during the unprecedented touch-and-go maneuver. With a delay of 18 minutes in radio communications, ground controllers for spacecraft manufacturer Lockheed Martin near Denver cannot intervene.
If the first attempt doesn’t work, Osiris-Rex can try again. All samples collected will not reach Earth until 2023.
While NASA brought back cometary dust and solar wind particles, it has never attempted to study any of the nearly 1 million known asteroids lurking in our solar system so far. Japan, meanwhile, expects to receive samples – in milligrams at most – from the asteroid Ryugu in December – 10 years after it brought back spots from the asteroid Itokawa.
Bennu is a paradise for asteroids.
The big, black, plump, carbon-rich space rock – taller than New York’s Empire State Building – existed when our solar system was formed 4.5 billion years ago. Scientists see it as a time capsule full of pristine building blocks that could explain how life formed on Earth and possibly elsewhere.
“This is about understanding where we come from,” said Mission Principal Scientist Dante Lauretta of the University of Arizona.
There are also selfish reasons to get to know Bennu better.
The solar orbiting asteroid, which oscillates on Earth every six years, could target us by the end of the next century. NASA estimates the probability of an impact at 1 in 2,700. The more scientists know about potentially threatening asteroids like Bennu, the safer the earth will be.
When Osiris-Rex blew up over $ 800 million on the mission in 2016, scientists envisioned sand tracks in Bennu. Therefore, the spaceship was designed to hold small pebbles with a diameter of less than 2 centimeters.
Scientists were stunned when the spaceship arrived in 2018 to find massive stones and chunky gravel everywhere. Occasionally, pebbles have been seen shooting off the asteroid, falling back, and sometimes ricocheting again in a cosmic game of ping pong.
With so much uneven terrain, engineers tried to aim for a narrower point than originally assumed. Nightingale Crater, the main target, appears to have the greatest amount of fine grains, but there are still plenty of boulders around, including one called Mount Doom.
Then COVID-19 struck.
The team fell behind and encountered the second and final dress rehearsal for the spaceship by August. That put the rehearsal hold on October.
“The return of a sample is difficult,” said the head of the NASA science mission, Thomas Zurbuchen. “The COVID made it even more difficult.”
Osiris-Rex has three bottles of nitrogen gas, which means it can touch down three times – no more.
The spaceship will automatically retreat when it encounters unexpected hazards such as large rocks that could cause it to tip over. And there’s a chance it might land safely but not collect enough debris.
Either way, the spaceship would return to orbit around Bennu and try another location in January.
On the first try here, Lauretta is finally worried, nervous, excited “and confident that we have done everything to ensure safe sampling.”
The Associated Press Department of Health and Science is supported by the Department of Science Education of the Howard Hughes Medical Institute. The AP is solely responsible for all content.