An asteroid would strike the Earth, and the collision of such a huge rock crashing into our planet would be catastrophic. A NASA spacecraft weighing less than 100 kg (220 lbs) will be launched to smash into an asteroid in order to shift it slightly off course as part of a planned NASA mission.
The goal of the test is to demonstrate that we are technologically prepared if a real asteroid danger emerges in the future.
On November 23, a SpaceX rocket lifted off from California with the Double Asteroid Redirection Test (DART), which will arrive at its target asteroid system in September 2020.
The objective will go to the Amor asteroid group member Didymos. Every 12 hours, a micro-moon, or “moonlet,” Dimorphos, orbits Didymos. This smaller half of the pair will be DART’s aim.
Are we in danger of dying out because of an asteroid impact?
An asteroid strike on Earth, similar to the one that wiped out the dinosaurs millions of years ago, has been a popular disaster scenario in films. Is that possible right now?
Almost all asteroids of this size, which may be as little as 1 to 20 meters in diameter, are bombarded frequently by tiny asteroids. Almost all such objects disintegrate in the air and are typically harmless.
The frequency of impact events is inversely related to the size of these things. This implies that we are hit more frequently by small objects than bigger ones – simply because there are many smaller ones in space.
Small asteroid impacts during the day (in yellow) and at night (in blue). Each dot is proportionate to the amount of optical radiated energy released by the collision.
Every 500,000 years, asteroids with a 1km diameter strike Earth. The most recent impact of this size is thought to have formed the Tenoumer impact crater in Mauritania 20,000 years ago. Asteroids with a diameter of around 5 kilometers hit Earth about once every 20 million years.
The 2013 Chelyabinsk meteoroid, which caused widespread damage in six Russian cities and injured over 1500 people, was thought to be approximately 20 meters across.
Analyzing the threat
The DART mission has been motivated by the potential and fear of a significant asteroid striking Earth in the future. nThe Torino scale is a method for classifying the impact danger posed by a near-Earth object (NEO).
It assesses risk on a range from 0 to 10, with 0 indicating that there is virtually no possibility of collision, and 10 denoting an imminent collision between the impacting object and global catastrophe.
A Torino Scale 10 is appropriate for the Chicxulub impact (which was caused by the extinction of non-avian dinosaurs). The Barringer Crater and the 1908 Tunguska explosion both have a Torino Scale 8.
With the rise of internet news and people’s ability to record events, asteroid “near-misses” have a habit of generating anxiety among the general public. NASA is presently keeping an eye on asteroid Bennu, which has the highest “cumulative hazard rating” at the moment. (You may also check out what’s new.)
Bennu has a 500-mile diameter, which means it may make a 5 kilometer crater on Earth. NASA claims there is a 99.943 percent chance the asteroid will miss us, nevertheless.
Prepare for the impact.
Didymos and Dimorphos come within 5.9 million kilometers of Earth at one point during their orbit around the Sun. This is still further than our Moon, but it’s not far in astronomical terms, so DART will strike Didymos when these two bodies are closest to each other in their orbits.
The DART spacecraft will travel for around ten months before crashing into Didymos, located 550 kilometers away. The two bodies will approach one another close enough that DART will alter course slightly to impact Dimorphos at a speed of 6.6 kilometers per second when the two bodies are near enough together.
Because the bigger Didymos has a diameter of 780 meters, it’s easier for DART to aim for. To collide with the moonlet, DART must detect the considerably smaller Dimorphos, which has a diameter of 160 meters.
The mass of Dimorphos is 4.8 million tonnes, and the DART impact will be about 550kg. DART will be able to deliver a significant amount of momentum to Dimorphos, enough to actually modify the moonlet’s orbit around Didymos when it travels at 6.6km/s.
DART’s thrusters would alter the angle of the spacecraft by about 1 percent, which will be detected by ground telescopes within weeks or months. While this may not appear to be much, 1% is actually encouraging. If DART were to smash into a single asteroid and cause its orbital period around the Sun to shorten by 0.000006%, it would take decades to observe such a tiny change.
So, when the pair gets to 1% away from us, DART will be able to detect the change. Meanwhile, the pair will continue on its orbit around the Sun. Before impact, DART will also deploy a tiny satellite that will capture everything in sight.
NASA’s first project dedicated to testing a planet-wide defense strategy was the NICER mission. In terms of space mission expenses, it is very low. The James Webb Telescope, which will be launched in late October, will cost about $10 billion.
There will be very little debris from the DART collision. Consider it to be an analog on Earth; imagine a train that has come to a halt on the tracks but without brakes. Another train comes along and collides with it, causing both trains to speed up.
The stationary train picks up speed while the one impacted loses momentum, resulting in no impact, ripples, or debris from the DART mission.
Is the time and effort really worth it?
The probe will be able to determine if a large impactor is needed, and it will also provide an understanding of how much mass and speed are required to destroy an asteroid that may become a hazard in the future. We already keep track of the vast majority of asteroids that approach Earth, so we would have warning if one passed by.
However, we have previously missed things. Asteroid UA_1 passed roughly 3,047 kilometers from Earth’s surface over Antarctica in October 2021. We missed it since it was approaching from the sun’s direction. It wouldn’t have caused much damage even if it was only 1m wide because we should have been able to predict it.
It would be difficult to construct a deflection system for a potential major asteroid hazard. We’d have to act fast and shoot the target with pinpoint accuracy.
The new technology developed by the US spaceflight firm SpinLaunch, which has developed technology to launch satellites into orbit at tremendous speeds, might be used in this manner. This gadget could also be used to bombard asteroids that are passing close by.
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