Asteroids are a big no no even if they happen to pass by earth, they are capable of causing devastating ripples across continents, let alone the destruction they could bring if they were to crash into the planet. A solution to completely rid of the problem is yet to surface, but what if they could be kicked or pushed away and should this give earth a slim chance of being hit by them? Well that’s precisely the technology what NASA is attempting to find out in its latest mission of trying to protect the planet from asteroids.
NASA’s mission, DART (Double Asteroid Redirection Test), is the world’s first planetary defense system launched into space by SpaceX’s Falcon 9 rocket, Vandenberg Space Force Base, California and is now making its way towards the sun.
Although there are no signs of a possible asteroid speeding towards earth, for now, this marks humanity’s first step in defending its planet against asteroids. As this mission carries an important goal and that is to know whether this solution could help the planet avoid asteroids, especially if they were to suddenly be spotted heading towards earth before other effective solutions are dug up.
According to NASA, “carrying out a real-world test on an asteroid with mostly unknown physical attributes is an essential next step to evaluate current models and enhance them further to address possibly hazardous asteroids in the future”.
Built by the Johns Hopkins Applied Physics Laboratory, Maryland, the journey of this mission will take nearly a year pacing towards an asteroid system of 6.5 million miles away from earth and the asteroid it's aiming to kick is not even a threat to the planet.
A Guinea Pig in Space
The asteroid in question practically poses no harm to earth, but NASA has chosen it as a test subject to trial out its mission. Named, Dimorphos, a 525 feet space rock revolving around its much larger counterpart, Didymos, which measures about 2,500 feet, are the chosen candidates to help discover the chances of crashing a spacecraft into an asteroid can change the direction in space. The reason for their qualification is that, Didymos is an eclipsing binary with a moonlet regularly hanging around it that makes it easy to notice when it passes in front the main asteroid.
For that matter, telescopes on earth have been eyeing the asteroids for decades and now comes the time to finally put this mission to the test even if it meant saving earth by a hair.
A Suicidal Deed
At a speed of around 6.6 kilometres per second, or 24,000 kilometres per hour, the spaceship will smash with it. As mentioned before, the collision is expected to take place around September 26 and October 1 next year.
Nancy Chabot, planetary scientist, Johns Hopkins University and the mission's coordination lead together with her team hope to explore if Dimorphos' almost 12-hour orbit may be altered by the cosmic encounter. The manoeuvre is expected to vary the speed of the space rock's orbit by a fraction of a percent, a difference of only a few minutes but ground-based telescopes should be able to detect the shift.
In the words of Chabot, “this isn't going to smash the asteroid, rather, a slight nudge. We're exhibiting asteroid deflection in this double asteroid system as it'll alter its route around the larger asteroid”.
DART is equipped with a camera, Draco, which will provide photos of both asteroids and assist the spacecraft in determining the best course for colliding with Dimorphos.
DART is likely to be smashed in the test, however, it is not going down without a last fight and that is placing an Italian-built cubesat over a week before the crash to send images of the impact including its aftermath to its soldiers on land. These will then go into another mission, Hera, investigating deep into the Didymos system added by the assessment of DART’s deflection.
Objectives of DART’s Mission
Demonstrate Dimorphos' kinetic impact.
Change Dimorphos' binary orbital period.
Measure Dimorphos' period change before and after impact using ground-based telescope observations.
Assess Dimorphos' reaction to the impact and the ejecta that ensue.
Will Humanity Find a Way Before Asteroids Do?
Firstly, the good news is that scientists are certain that no asteroids larger than 1km will reach earth for the next century, giving humanity the longest time frame to observe the movements of asteroids and come up with successful solutions.
What's more, even among much smaller asteroids, those larger than 140 metres, there are no known objects with a considerable likelihood of colliding with Earth within the next 100 years.
However, the bad news is that just 40 percent are seen to be lurking in space and what’s even worse is that asteroids as tiny as 140 metres can cause severe damage to cities or towns.
Humanity's ability to detect asteroids before they collide with the planet is still in its early stages, in part due to physics' limitations like the ability to survey asteroids in the dark of space in the earth’s solar system. As it is based on the asteroid’s light reflecting towards the planet, which is dependent on the direction of their approach relative to the sun and the phase of the moon.
Light applies even in the case of DART, as the binary is incredibly tiny that it appears as a single point of light to even the most powerful telescopes. But, as it passes in front of Didymos, Dimorphos blocks some of Didymos' reflected light, and when the smaller object passes behind its larger companion, the opposite occurs.
"We can detect the frequency of those dimmings”, Dart research head Andy Rivkin noted, adding, that they Dimorphos orbits Didymos for 11 hours, 55 minutes.
This timescale allows for far less flexibility than the five years between NASA's approval of the DART mission and its planned rendezvous with Dimorphos next year.
However, astronomers hope and anticipate that new technologies and monitoring systems will improve humanity’s ability to make these predictions in the future, giving humans more time, and the DART mission is just the first step in demonstrating that there is something humans can do knowing that something bad is approaching.