Cape Town, Florida (Associated Press)-After orbiting hundreds of millions of miles of ancient asteroids for nearly two years, NASA’s spacecraft this week will attempt to descend to the surface of sinister, boulder-piled surfaces and seize A small amount of gravel.
As the United States collected asteroid samples for the first time and returned to Earth, the drama began on Tuesday. So far, this feat has only been accomplished by Japan.
The Osiris-Rex mission, full of names inspired by Egyptian mythology, is trying to bring back at least 2 ounces (60 grams) of asteroid Bennu, the largest otherworldly vehicle from outside the moon .
The goal of this minivan is to target a relatively flat place called Nightingale, the size of a tennis court crater-this place is comparable to some parking spaces on Earth. A boulder the size of a building is shrouded in the target grounding area.
“So, from a certain perspective, the next time you park your car in front of a house or coffee shop and walk in, consider the challenge of navigating Osiris-Rex to one of the locations 200 million miles away. ,”
Once it leaves Bennu’s half-mile high (0.75 kilometers high) orbit, it will take the spacecraft four hours to fully descend above the ground.
Then, when Osiris-Rex’s 11-foot (3.4-meter) arm stretched out and touched Bennu, the movement accelerated. The contact should last for five to ten seconds, just enough to emit pressurized nitrogen and absorb the stirred dust and gravel. Pre-programmed, the spacecraft will operate autonomously in an unprecedented trigger and launch operation. Each method of radio communication lags 18 minutes, so the ground controller of the spacecraft manufacturer Lockheed Martin near Denver cannot intervene.
If the first attempt does not work, Osiris-Rex can try again. Until 2023, all collected samples will not reach the earth.
Although NASA brought comet dust and solar wind particles, so far, it has never attempted to sample one of the nearly one million known asteroids lurking in our solar system. At the same time, Japan is expected to obtain samples from the Ryugu asteroid 10 years (at most in milligrams) after the spots were taken from the asteroid Longchuan in December.
Bennu is a paradise for asteroid pickers.
When the solar system was formed 4.5 billion years ago, a large, black, circular, carbon-rich space rock (higher than the Empire State Building in New York). Scientists believe that this is a time capsule full of primitive ingredients that can help explain how life forms on Earth and elsewhere.
The chief scientist of the delegation, Dante Lauretta of the University of Arizona, said: “It’s all about understanding our origins.”
There are also some selfish reasons to understand Bennu better.
A solar-orbiting asteroid that revolves around the earth every six years may target us at the end of the next century. NASA estimates that the probability of impact is 1 in 2,700. More and more scientists know that with potentially threatening asteroids like Bennu, the earth will be safer.
When Osiris-Rex exploded with a mission of more than $800 million in 2016, scientists envisioned stretching in the Bennu sands. Therefore, the spacecraft is designed to capture small pebbles less than 1 inch (2 cm) wide.
When the spacecraft arrived in 2018, the scientists were stunned and huge rocks and thick gravels were found everywhere. Occasionally, pebbles can be seen shooting from asteroids, falling back, and sometimes bouncing again in a space table tennis game.
Faced with so many rugged terrain, engineers scrambled to aim at a narrower location than initially expected. The primary target is the Nightingale Crater, which contains the largest number of fine particles but is still full of boulders, including a boulder called Doom Mountain.
Then COVID-19 struck.
The team fell behind and performed the rehearsal for the second and final contact flight until August. That pushed the sample rush to October.
“Returning samples is very difficult,” said Thomas Zurbuchen, NASA’s scientific mission leader. “The COVID makes it more difficult.”
Osiris-Rex has 3 bottles of nitrogen, which means it can land 3 times and never again.
If the spacecraft encounters an unexpected hazard (such as a large rock that may cause it to tip over), it will automatically retract. And it might land safely, but could not collect enough rubble.
In either case, the spacecraft will return to orbit near Bennu and try again in another location in January.
When finally making the first attempt here, Lauretta felt worried, nervous, excited, “and confident that we have done everything possible to ensure the safety of sampling.”
The Associated Press Department of Health and Science is supported by the Howard Hughes Medical Institute’s Department of Science Education. AP is solely responsible for all content.