NASA has spent seven years trying to prevent Bennu — an asteroid taller than the Empire State Building and named after ancient Egypt‘s fiery bird-god — from crashing cataclysmically into Earth.

While Bennu’s chances of impact are just 1-in-2,700, more than five times a person’s chance of being struck by lightning, NASA’s team nevertheless has categorized it as one of the two ‘most hazardous known asteroids.’

In a worst-case scenario, the roughly 510-meter wide, carbon-based behemoth would smash into Earth with 1,200 megatons of energy: 24 times the power of the largest nuclear bomb ever detonated (the Soviet Union’s ‘Tsar Bomba‘).

If it happens, Bennu’s impact would unleash its 1.2 gigaton impact 159 years from this Sunday, on September 24, 2182.

While Bennu is nowhere near the size of the dino-killing, six-mile across space rock that hit the Yucatan 66 million years ago, astronomers believe that the asteroid ‘could cause continental devastation if it became an Earth impactor.’

When NASA dispatched its OSIRIS-REx spacecraft for a rendezvous with the asteroid on September 8, 2016, part of its mission was to trail Bennu for two years from 2018 to 2020 collecting data to better calculate its future path. 

‘We improved our knowledge of Bennu’s trajectory by a factor of 20,’ Davide Farnocchia of NASA’s Jet Propulsion Laboratory told the journal Science.

Provided humanity lasts that long, NASA will conduct its final risk calculations on Bennu’s orbit during its next near-Earth pass in 2135 – about 47 years before its potential impact.  

‘In 2135, we’ll know for sure,’ Farnocchia said.

In the meantime, Bennu, not unlike its namesake god of creation and rebirth, also has something to tell us about the birth of our solar system.

NASA’s OSIRIS-REx went to Bennu equipped with the tools to map the ancient asteroid, a sort of time capsule of the early solar system, and collect rare samples of this nearly untouched material.

This Sunday, the OSIRIS-REx will drop a payload of 8.8 ounces (250 grams) from its Bennu mission back down to Earth, as the probe skates past approximately 485 miles above our planet’s surface toward its next asteroid rendezvous mission.  

‘This is pure untainted material revealing early solar system secrets,’ astrophysicist Hakeem Oluyesi of Princeton Plasma Physics Laboratory told ABC News about the samples.   

‘A longshot discovery would be finding biological molecules or even precursor molecules for life,’ according to Oluyesi.

OSIRIS-REx was not only the US space agency’s first-ever asteroid sample collection run.

It is now poised to also become the largest-ever asteroid-sampling mission, besting Japanese space agency JAXA’s collection of 5.4 grams from the asteroid Ryugu in 2020.

But OSIRIS-REx’s mission is still days away from successful completion. 

‘It feels very much like the last few miles of a marathon,’ said Rich Burns, the OSIRIS-REx project manager at NASA’s Goddard Space Flight Center. 

‘A confluence of emotions like pride and joy, coexisting with a determined focus to complete the race well.’

After careening across 63,000 miles of our solar system, and now hurtling towards Earth at a breakneck 28,000 mph, OSIRIS-REx will release its capsule of samples at approximately 4:42 AM Mountain Time (10:42 AM UTC) over Utah. 

The capsule, about the size of a mini-fridge and prepared to withstand friction temperatures twice as hot as molten magma, will be slowed in its descent to Utah’s Great Salt Lake Desert by parachutes. 

Researchers plan to recover the samples from a pre-planned 36-mile by 8.5-mile area on the Pentagon’s Utah Test and Training Range southwest of Salt Lake City. 

Touchdown is expect at a little before 9:00 AM Mountain Time.

All the data collected by the OSIRIS-REx will help in future efforts to deflect Bennu in the event of a worst case scenario. 

But planetary scientist Lindley Johnson of NASA’s Planetary Defense Coordination Office believes such a dire case is unlikely.

‘I don’t think we need to do anything about Bennu,’ as Johnson told Science.

‘This data set [from OSIRIS-REx] will be enormously valuable in assessing deflection technologies,’ according to Johnson who believes that the nearly 50-year window between 2135 and 2182 will be plenty of time to mount an Armageddon-style deflection mission.

Nonetheless, if Bennu were to impact Earth, it would be similar to an explosion of more than 1.1 billion tons of TNT. 

Kelly Fast, program manager for the Near-Earth Object Observations Program at NASA Headquarters in Washington, said in a statement: ‘NASA’s Planetary Defense mission is to find and monitor asteroids and comets that can come near Earth and may pose a hazard to our planet. 

‘We carry out this endeavor through continuing astronomical surveys that collect data to discover previously unknown objects and refine our orbital models for them.

‘The OSIRIS-REx mission has provided an extraordinary opportunity to refine and test these models, helping us better predict where Bennu will be when it makes its close approach to Earth more than a century from now.’

NASA last updated its estimates of the planetary risks posed by Bennu in November 2021, with a paper entitled ‘Ephemeris and hazard assessment for near-Earth asteroid (101955) Bennu based on OSIRIS-REx data,’ published in the journal Icarus.  

While there is a slight chance Bennu will collide with Earth over the next three centuries, the space agency notes there is more than a 99.9 percent probability it will not. 

Back in 2020, NASA unveiled stunning videos and images showing the moment the spacecraft pulled off its six-second touch-and-go (TAG) mission where it bounced off the Bennu’s surface and picked up samples along the way.

Once completed Sunday, the triumphant $1.16 billion mission will be the first American effort to take a sample from an asteroid with the hopes to unlock secrets about the origin of life on Earth.

NASA’s October 2020 images show how the spacecraft descended within three feet of the target landing spot dubbed Nightingale on the asteroid while avoiding boulders the size of buildings. 

Upon contact, the spacecraft’s 11-foot robotic arm can then be seen smashing some porous rock upon initial impact with the surface.

A nitrogen gas bottle then fired on the surface to stir up material and suck it up in a ‘rubble shower’.

The spacecraft spent five seconds of the six seconds on Bennu collecting the material before backing away, with a majority of the sample collected in the first three seconds.

Three years later, fruits of those six seconds, a smaller safer piece of Bennu will finally collide gently with Earth. 

It has been billed as NASA’s ‘asteroid autumn’ and involves a trio of exciting missions that could answer some truly mind-boggling questions.  

From offering clues to how life on Earth began, to unlocking the secrets of the solar system, key milestones for each voyage are due to play out over the next six weeks.

They include one rocket launch, a distant fly-by between Jupiter and Mars, and the recovery of ancient space rocks in the Utah desert that could contain the ingredients for life.

Of the three, the lift-off of NASA’s Psyche spacecraft probably sounds the most mundane — but no so fast.

That is also a fascinating mission, because it is setting off on a 2.5 billion-mile (4 billion-kilometre) journey to find out once and for all if a metal-rich asteroid really could bring down the world’s economy. 

1. Visit to $10,000 QUADRILLION space rock

Psyche is due to lift-off on October 5 on its way to the asteroid 16 Psyche, which scientists think may be packed full of precious metals with a value in excess of $10,000 quadrillion (£8,072 quadrillion).

Others dispute this and say it is just hard rock, but NASA should be able to tell either way when its orbiter gets to the asteroid in July 2029. 

One thing it definitely won’t look like is anything resembling what you might find in a jewellery store, however. 

‘I would love for it to look like a shiny, polished, what’s called a pallasite meteorite — with the shiny silver metal and the beautiful gold and green jewel-like silicate minerals in between,’ said Lindy Elkins-Tanton, the mission’s principal investigator.

‘But it’s not going to look like that. Because no one’s been onto Psyche, cut it open and polished it.’

She added: ‘It’s been hanging out in space, getting solar wind hitting it for a really, really long time. So the surfaces are not likely to be shiny.’

If 16 Psyche is in fact loaded with precious metals, it could be worth a huge amount of money, according to Dr Linda Elkins-Tanton, a space scientist at MIT. 

She has calculated that the iron in 16 Psyche alone would be worth $10,000 quadrillion (£8,072 quadrillion). 

Assuming the market for asteroid materials is on Earth, this could cause the value of precious metals to plummet, completely devaluing all holdings including those of governments, and all companies involved in mining, distributing and trading such commodities. 

Ultimately, it could lead to the collapse of the entire economy.

Of course it’s all speculative and hypothetical, because even if the space rock was worth anywhere close to that kind of money, it’s not like it could easily be brought back to Earth.

Engineers in California are currently getting the spacecraft ready to journey to 16 Psyche, which sits in the main asteroid belt between Mars and Jupiter.

The orbiter is due to piggy-back into space on a SpaceX Falcon Heavy rocket which is scheduled to lift off from Pad 39A at Kennedy Space Center in Florida no earlier than 10:38 ET (15:38 BST) on October 5. 

2. Recover sample from a 4.5 billion-year-old asteroid 

A separate team of NASA scientists is also gearing up to recover a capsule containing fragments of the asteroid Bennu.

The 8.8oz (250g) sample of rock and dust will be dropped back to Earth by the OSIRIS-REx spacecraft and is due to land in Utah’s western desert on September 24.

An acronym for ‘Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer’, OSIRIS-REx became the first US mission to collect a sample from an asteroid when it briefly touched down on Bennu in October 2020 and scooped up material with its robotic arm. 

The space rock is about the size of the Empire State Building and around 200 million miles away from us.

It is of great interest to scientists because it is believed to contain microscopic mineral grains that pre-date the solar system.

This carbon-rich material is also thought to hold the preserved building blocks of life and could help experts better understand how the planets were formed and how life originated on Earth.

The sample that OSIRIS-REx recovered is the largest by a NASA mission since the Apollo astronauts returned with moon rocks in the 1960s and 70s.

It will be brought back to Earth and land at the Utah Test and Training Range in just over a week’s time. 

The precious rocks and dust will then be housed at a new lab at NASA’s Johnson Space Center in Houston, which is home to hundreds of pounds of lunar material collected by the 12 Apollo moonwalkers.

3. Fly-by on the way to Jupiter’s Trojans

Meanwhile, a spacecraft named Lucy – launched in October 2021 to study eight asteroids that orbit Jupiter – will pass its first space rock called Dinkinesh on November 1.

During its 12-year journey the probe will be the first to tour the so-called Trojan asteroids, which are seen as ‘time capsules from the birth of our solar system’. 

Although Lucy will get its first close-up look at a space rock in six weeks’ time, its maiden Trojan asteroid flyby will not happen for another four years, when the spacecraft gets closer to Jupiter in August 2027.

The vast majority of the asteroid visits will happen in 2027 and 2028, with a final asteroid flyby scheduled to happen in March 2033.

The first will take place in April 2025, when Lucy visits a space rock in the main asteroid belt beyond Mars known as Donaldjohanson. 

This will be followed by a trip to seven Trojan asteroids that are named after characters from Greek mythology.

They are Eurybates, Queta, Polymele, Leucus, Orus, Patroclus and Menoetius.  

All of the Trojans are thought to be abundant in dark carbon compounds.

Below an insulating blanket of dust, they are probably rich in water and other volatile substances, dating back to the first days of the solar system.

No other space mission in history has been launched to as many different destinations in independent orbits around our sun. Lucy will show us, for the first time, the diversity of the primordial bodies that built the planets. 

NASA has said the $981 million (£715 million) mission will revolutionise our knowledge of planetary origins and the formation of the solar system, giving insight into planetary evolution. 

It takes its name from the fossilised human ancestor, named ‘Lucy’ by her discovers, whose skeleton provided unique insights into our evolution. 

As well as viewing some of the oldest rocks in the solar system, Lucy’s path will cross the Earth three times, as it uses our planet’s gravity to aid in its positioning.

This move will make it the first ever spacecraft to return to Earth from the outer solar system, as all the others are either still going – in the case of the Viking probes – or burnt up in the atmosphere of a gas giant, as was the case with Cassini and Saturn.