In a “nail-biting manoeuvre”, a Nasa spacecraft will “fist bump” a diamond-shaped asteroid named Bennu. The spacecraft will approach the asteroid some 334 million kilometres away from Earth with an aim to touch its surface for a few seconds. In the process, the Nasa spacecraft is expected to collect a handful of rubble. The craft will then fly the “carbon-rich” pebbles back to Earth.
The “Touch-And-Go (TAG) sample collection event” will take place on Tuesday. If successful, it will be a historic moment, the National Aeronautics and Space Administration (Nasa) has said. The process will take a total of 4.5 hours, however, the “touching” will be only for 10-15 seconds.
According to a report in the journal, Nature, Nasa’s OSIRIS-REx spacecraft will try to scoop at least 60 grams of rock samples from the asteroid Bennu. The rubble will be used to probe the history of the Solar System.
The van-sized spacecraft is aiming for the relatively flat middle of a tennis court-sized crater named Nightingale — a spot comparable to a few car parking places on Earth. Boulders as big as buildings loom over the targeted touchdown zone.
THE JOURNEY TO AND FROM
The Nasa spacecraft will have to move past certain hurdles to make it to asteroid Bennu. The journey won’t be easy. “The spacecraft will have to navigate its way past a towering boulder nicknamed Mount Doom, then onto a sampling area no larger than a few car-parking spaces,” the Nature report said.
“We may not be successful on our first attempt,” the report quoted Dante Lauretta, the mission’s principal investigator and a planetary scientist at the University of Arizona in Tucson, as saying. But if it works, he said, “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.”
“If you could stand in the middle of Nightingale [the target area for the mission], you would feel pebbles and fine-grained sand beneath your feet,” the report quoted Erica Jawin, a planetary scientist at the Smithsonian National Museum of Natural History in Washington DC, as saying.
“Mount Doom would loom above you, roughly the height of a two-storey building, which is “pretty intimidating”, she said.
The process will last just 10-15 seconds and is more like a ‘fist bump’ than a landing, the report said. The spacecraft will automatically move back if it encounters any unexpected hazards like big rocks that could cause it to tip over. There’s also a chance that it will touch down safely but fail to collect enough pebbles and dust.
In these two cases, the spacecraft would return to orbit around Bennu and try again in January at another location. Nasa wants at least 60 grams of rocks and dust. “If it’s 58 grams, we’re stowing and coming home,” Lauretta was quoted as saying. Any collected samples will not arrive at Earth until 2023.
The report says that collecting rubble samples directly off an asteroid offers a “pristine glimpse at rocks left over from the formation of the Solar System more than 4.5 billion years ago”.
Scientists suspect that asteroid Bennu might contain material that is rich in organic compounds and that are found throughout the Solar System, including in life on Earth. It is believed that on this asteroid, water which is another vital component to the evolution of life may also be trapped in the asteroid’s minerals.
According to the report, scientists will also investigate Bennu’s rocks for ways to protect Earth from asteroids, which zoom past the blue planet almost every day.
OSIRIS-REx is Nasa’s first asteroid-sampling mission launched in 2016. “It follows two missions from the Japan Aerospace Exploration Agency [JAXA] that have scooped dust off the surface of asteroids – including some retrieved last year that is currently on its way back to Earth for analysis,” the Nature report said.
When Osiris-Rex blasted off on the more than $800 million mission, scientists suspected sandy stretches at asteroid Bennu. Therefore, the spacecraft was designed to ingest small pebbles less than an inch (2 centimetres) across.
However, scientists were stunned to find massive rocks and chunky gravel all over the place when the spacecraft arrived in 2018.
According to a report, Osiris-Rex has three bottles of nitrogen gas, which means it can touch down only three times.
Bennu is an asteroid picker’s paradise. The big, black, roundish, carbon-rich space rock – taller than New York’s Empire State Building – was around when our solar system was forming 4.5 billion years ago, news agency AP reported.
“It was formed between around 100 million years and one billion years ago, when it broke away from a larger ‘parent’ body during a cosmic collision in the Solar System’s asteroid belt,” the Nature report said.
Originally published by Indiatoday