Saving Earth from an Asteroid: NASA to smash its spacecraft into one; SpaceX launch soon

The danger of an asteroid crashing into the Earth is quite clear. NASA wants to protect Earth by crashing a spacecraft into an asteroid. Called DART, it will launch soon on a SpaceX Falcon 9 rocket.

Saving Earth from Asteroid crash: Schematic of the DART mission shows the impact on the moonlet of asteroid (65803) Didymos. Post-impact observations from Earth-based optical telescopes and planetary radar would, in turn, measure the change in the moonlet’s orbit about the parent body.   (NASA/Johns Hopkins Applied Physics Lab)

One of the greatest fears of humanity is a piece of rock, an asteroid, crashing into Earth that sends humans, the way of the dinosaurs - into extinction. Now, whether dinosaurs went extinct due to an asteroid crashing into Earth is still being debated, there is no gainsaying the fact that they are as dead as the Dodo, so to speak. And a lot of water, among other things, has passed down the Ganges when it comes to talking about asteroids. No, their potential for destruction is still held in fear and that is not about to change, but the difference is that there are some folks at NASA who are actually trying to devise a strategy for the time when an asteroid heads straight for the Earth and threatens to take out all life on it. The idea is to crash a spacecraft into an asteroid as an experiment and do it soon - the mission will launch on a SpaceX Falcon 9 rocket and it is called the Double Asteroid Redirection Test (DART).

Before this sets off a round of scare-mongering, let it be clear that there is no asteroid headed for Earth that we know of. However, having said that, there are many things humans don't know. An example being that just a few days ago, a very small asteroid was noticed by astronomers just hours before it shot past the Earth. Almost no warning came. Even if it had crashed, however, it would have done no damage to Earth, except cause some great light effects up in the sky when it burned out on entering the Earth's atmosphere. However, the surprise was unpleasant.

The truth is that there are giant asteroids out there and when one will arrive is clear to no one. However, the folks at NASA have been working on it. The idea is to thwart the asteroid and save humanity. How? By crashing a spacecraft into the asteroid before it smashes into Earth.

NASA has something called a Planetary Defence Coordination Office and it is working on a mission to destroy or deflect asteroids heading for Earth. The mission is called the Double Asteroid Redirection Test (DART). NASA says, "DART is a planetary defense-driven test of technologies for preventing an impact of Earth by a hazardous asteroid."

What DART will do is demonstrate the kinetic impactor technique to change the motion of an asteroid in space.

As said above, DART spacecraft will crash into an asteroid to see what happens. Something on the lines of, but not exactly the same as, Armageddon movie, starring Bruce Willis, Liv Tyler and Ben Affleck.

And yes, a suitable candidate, a target asteroid, has already been chosen. And no, it is not heading for Earth. The binary near-Earth asteroid (65803) Didymos is the target for the DART demonstration. NASA says, "While the Didymos primary body is approximately 780 meters across, its secondary body (or “moonlet”) is about 160-meters in size, which is more typical of the size of asteroids that could pose the most likely significant threat to Earth." It is the moonlet that will be targetted by DART.

And NASA is going about planning the destruction of Didymos ruthlessly. The asteroid is being intensely observed using telescopes on Earth to precisely measure its properties and then it will send across DART at the most opportune moment for the biggest impact.

NASA says, "The DART spacecraft will achieve the kinetic impact deflection by deliberately crashing itself into the moonlet at a speed of approximately 6.6 km/s."

What the collision will do is change the speed of the moonlet in its orbit around the main body by a fraction of one percent. This will also change the orbital period of the moonlet by several minutes. This will be observed through telescopes from Earth to gauge exactly how successful the mission was in moving the moonlet or measure the change in momentum imparted to the moonlet.

The launch is not far off either. The DART spacecraft launch window begins November 24, 2021 and it will launch aboard a SpaceX Falcon 9 rocket. After over a year's worth of cruising it will intercept Didymos' moonlet in late September, 2022, when the Didymos system is within 11 million kilometers from Earth.