It was the year 2022 and living organisms are threatened by an asteroid but not the type that wiped out the dinosaurs. The asteroid is a threat to living organisms and everyone is worried about what will happen but an organization stepped up and devised a plan which destroy the asteroid and every organism on Earth lived happily ever after.
Except that’s probably not how the story will go but you get the point. A NASA spacecraft, the size of a golf cart has been directed to smash into an asteroid with the aim of sending it off course.
The main aim is to demonstrate how ready humans are in case there is an actual asteroid threat in the future.
Back on November 23rd, the Double Asteroid Redirection Test or DART, in short, lifted off aboard the SpaceX rocket from California, and it’s expected to reach the targeted asteroid system by September 2022.
NASA’s spacecraft will travel to the asteroid Didymos which is a member of the Amor Group of asteroids.
The asteroid system has its own mini-moon called Dimorphos which orbits it every 12 hours and it’s the actual target of NASA’s DART.
Are we doomed?
Even though I mentioned in my short sci-fi tale that the human race was under threat, well, not like this one.
The reality is that there are often asteroid bombardments on the planet but their impacts are so insignificant that they barely make big news headlines because most of them get disintegrated in the atmosphere.
According to scientific reports, there is an inverse relationship between the size of the space rocks and how frequently they collide with Earth.
With that said, we’re more prone to smaller and insignificant asteroids compared to the larger ones that can pose actual threats.
Researchers also noted that asteroids with a 1KM diameter strike the planet every 500,000 years on average with the most recent of this size thought to have led to the formation of the Tenoumer impact crater in Mauritania, 20,000 years ago.
Bigger ones with a 5km diameter impact the planet about once in every 20 million years.
The 2013 Chelyabinsk meteoroid, which damaged buildings in six Russian cities and injured around 1,500 people, was estimated to be about 20m in diameter.
Risks posed by asteroids on organisms
With concerns growing over the size of future asteroid impacts on the planet, NASA’s DART mission is the experimentation to understanding how we can potentially send these space rocks off course.
The Torino scale is a method for categorizing the impact hazard associated with a near-Earth object (NEO). It uses a scale from 0 to 10, wherein 0 means there is a negligibly small chance of collision, and 10 means an imminent collision, with the impacting object being large enough to precipitate a global disaster.
The Chicxulub impact (which is attributed to the extinction of non-avian dinosaurs) was a Torino Scale 10.
The outcome of an impact that led to the formation of the Barringer Crater as well as the 1908 Tunguska event both of which correspond to Torino Scale 8.
NASA is keeping its eyes close on asteroid Bennu which is the largest “cumulative hazard rating” right now.
The asteroid has a diameter of about 500m and is capable of creating a 5km crater on Earth if it ever crashes on the planet even though NASA believes the chance of ever colliding with Earth is very tiny.
At one point in their orbit around the Sun, Didymos and Dimorphos come within about 5.9 million km of Earth. This is still further away than our Moon, but it’s very close in astronomical terms, so this is when DART will hit Dimorphos.
DART will then travel for about ten months towards Didymos and when it’s close enough, it will change direction slightly in order to crash into Dimorphos at a speed of about 6.6km per second.
The mass of Dimorphos is about 4.8 million tonnes and the mass of DART at impact is about 550kg.
Even though the size of DART may not be significant, the speed at which it will be traveling will help it transfer enough momentum to Dimorphos to the point where it’s expected to change the moonlet’s orbit around Didymos.
Then NASA’s observers will make use of ground telescopes to check the result of the impact which is expected to be about 1%.
Before the impact, DART will deploy a small satellite ten days earlier before the collision. The satellite will be used to capture the entire event.
After the collision, the pair of asteroids will continue along their orbit around the sun but the point has been achieved – a 1% shift off course.
The project costs about US$330M which is quite cheaper when compared to other space missions. It’s also NASA’s first mission dedicated to demonstrating planetary defense techniques.
There will be little to no debris from DART’s impact. We can think of it in terms of a comparable event on Earth; imagine a train parked on the tracks but with no brakes on. Another train comes along and collides with it.
The trains won’t break apart, or destroy one another, but will move off together. The stationary one will gain some speed, and the one impacting it will lose some speed. The trains combine to become a new system with different speeds than before.
So we won’t experience any impact, ripples, or debris from the DART mission.
The first big step
At the conclusion of the mission, the results will show us how much mass and speed are needed to hit an asteroid that could be a potential threat in the near future.
Also, NASA has technologies powerful enough to track the vast majority of asteroids that come close to the planet which means there will always be an early warning in case of a future threat.
Even though there have been instances of those advanced technologies missing out on an asteroid in the past one of which is Asteroid UA_1 which passed about 3,047km from Earth’s surface over Antarctica.
The main reason the asteroid was said to have been missed is due to the direction from which it approached – from the sun.
Although the size of the asteroid was just 1m, it wouldn’t cause too many damages on the planet but the fact that it was missed, even in Oct. 2021 means asteroids can still sneak in on us without detection.
Creating a powerful deflection system for a potentially threatening asteroid in the future will be a big and difficult task to accomplish and some might say why not nuke them, it’s not just that easy.
And that is why NASA is constantly pouring millions into researches to understand how things work.
One of the breakthrough inventions is the proposed SpinLaunch from a US spaceflight company.
The technology is designed to launch satellites into orbit at rapid speeds and the device could be used to fire masses at close-passing asteroids if needed.