After nearly two years circling an ancient asteroid hundreds of millions of miles away, a NASA spacecraft this week will attempt to descend to the treacherous, boulder-packed surface and snatch a handful of rubble.
This is a different approach to the one that took place a year ago in which Japan's Hayabusa2 spacecraft collected two samples from near-Earth asteroid Ryugu. The van-sized spacecraft must negotiate building-sized boulders around the landing area to land in a relatively free space that is only as large as a few parking spaces. The OSIRIS-REx spacecraft launched from Cape Canaveral on September 8, 2016, and took more than two years to arrive at 101955 Bennu, a diamond-shaped object with a mean diameter of about 1,600 feet, slightly bigger than the Empire State Building.
"So for some perspective, the next time you park your vehicle in front of your house or in front of a coffee shop and walk inside, think about the challenge of navigating Osiris-Rex into one of these spots from 200 million miles away", said NASA's deputy project manager Mike Moreau.
The descent to Bennu's surface takes about four hours, roughly the time it takes for the asteroid to complete one full revolution.
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. With an 18-minute lag in radio communication each way, ground controllers for spacecraft builder Lockheed Martin near Denver can't intervene.
If the first try doesn't work, Osiris-Rex may try again.
The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer mission, better known as OSIRIS-REx, is set to collect samples of an asteroid named Bennu on October 20, at 6:12 p.m. EDT.
While NASA has brought back comet dust and solar wind particles, it's never attempted to sample one of the almost 1 million known asteroids lurking in our solar system until now.
Bennu is an asteroid picker paradise. At a diameter of 1,607 feet, it is the size of the Empire State Building in NY and is said to contain ingredients of life necessary on Earth, making it a recent subject of interest for scientists.
Benu is considered to be a window into the past of the solar system: an ancient, carbon-rich body that carries the building blocks of both planet and life.
"It's all about understanding our origins", said Dante Lauretta, chief scientist at the University of Arizona.
There also are selfish reasons for getting to know Bennu better. Its orbital period is 1.2 years, coming close to Earth every six years. NASA has set the probability of impact to 1-in-2,700.
The asteroid has another property that makes it particularly interesting for scientists and humans in general - it has the chance to affect Earth in the distant future. Here's everything to learn more about Osiris-Rex, Bennu and NASA's plan to launch a planet. Therefore, the spacecraft is created to take in small pebbles less than 2 centimeters in diameter. 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, engineers scrambled to aim for a tighter spot than originally anticipated. The main target, the Nightingale Crater, appears to have the most microscopic particles, but is still rocky, including a rock named Mount Doom.
The team fell behind and had a second and final touch-and-go dress rehearsal for the spaceship by August.
We will begin indexing and analyzing the sample once it is returned on September 24, 2023, Dorkin says. "The COVID makes it even more hard".
Osiris-Rex has three bottles of nitrogen gas, which means it can touch down three times - no more. Of the Return flight Direction earth is with about three years of travel time even covered a little faster than the outward flight.
The spacecraft automatically will back away if it encounters unexpected hazards like big rocks that could cause it to tip over.
The sampler head that will touch the asteroid is a bit larger than a dinner plate, and the goal is for it to collect anywhere from 60 grams to 2 kilograms (about 2 ounces to 4.5 pounds) of material.
With the first try finally here, Lauretta is anxious, nervous, excited "and confident we have done everything possible to ensure a safe sampling".