Asteroid, Comet Threat: What is NASA's Plan When Space Rocks Hit Earth?

Approximately 30,000 objects are drifting near Earth that may collide with it at any time, with 1,600 of them classified as "possibly dangerous" by NASA.

Scientists are working hard to locate and, if necessary, deflect or destroy these renegade space objects, which might result in anything from shattered windows to worldwide extinction.

According to The Conversation, NASA allocated $158 million for planetary defense in 2021. It is only 0.7 percent of NASA's entire budget and 0.02 percent of the nearly $700 billion defense budget for 2021. The budget support various missions, including the NEO Surveyor, valued at $83 million, DART, valued at $324 million, and Osiris Rex, valued at about $1 billion. Will these numbers, however, be of help?

NASA Planetary Defense

The notion of planetary defense is an important aspect of NASA's broader mission: defending Earth from asteroids and other space objects that could collide with our planet. It's also the aspect of NASA's mission that piques the public's and Hollywood's interest the most.

Various techniques that NASA may try to stop an asteroid or comet traveling toward our planet have been shown in films such as Armageddon and Deep Impact, The Verge said. Both films, however, depict people flying to the space rock that would bring us all to our demise - a scenario that would very certainly never happen due to the enormous complexity and safety concerns such a voyage would entail.

Humanity finds an asteroid the size of Texas just 18 days before it collides with the planet in Armageddon. Given NASA's ongoing search for such objects, a planet-killing asteroid on such short notice is likewise doubtful. The two Pan-STARRS telescopes in Haleakala, Hawaii, are now our most important asteroid hunters, scanning the sky for asteroids we haven't yet discovered. Scientists can calculate the objects' routes around the Sun once they've been found and determine if they'll ever collide with our planet. We know of no asteroids that will pose a threat in the next 100 years, and we've discovered the majority of the larger ones that may inflict worldwide catastrophe.

It's still possible, though, that we'll be shocked one day. According to NASA, only approximately 40 percent of all near-Earth asteroids larger than 140 meters (460 feet) wide have been discovered. These are the ones that would cause unspeakable havoc if they strike a populated region. And we've been caught off guard before by deadly space objects. A house-sized meteor exploded in the sky over Chelyabinsk, Russia, in 2013, with little warning, generating an explosion equivalent to 440,000 tons of TNT and wounding over 1,600 people.

Even though the Chelyabinsk meteor was just 18 meters (60 feet) broad, it caused significant damage. That's why NASA is on a mission to identify asteroids with a diameter of 140 to 150 meters. Mass casualties, refugee problems, political instability, supply chain disruptions, and other consequences might result from one.

How NASA Would Exactly Help The Planet vs. Asteroids

Early detection is essential for the planet to be safe from cosmic hazards. Scientists at the 2021 Planetary Defense Conference (per Big Think) indicated that a successful defense against dangerous asteroids needs five to 10 years of planning.

If astronomers uncover a dangerous asteroid, there are four options for avoiding disaster. The first is a set of first-aid and evacuation guidelines for the region. A second possibility would be to launch a spacecraft near a small or medium-sized asteroid, which would gradually modify the asteroid's orbit due to the craft's gravity.

Experts can either smash something into it at high speeds or explode a nuclear bomb nearby to modify the route of a larger asteroid.

These may sound like far-fetched concepts, but NASA launched the world's first full-scale planetary defense mission, the Double Asteroid Redirection Test (DART), in November 2021 as a proof of concept.

At present, a massive asteroid called Didymos and its tiny moon pose no threat to Earth. In September 2022, NASA plans to change the asteroid's orbit by hitting a 1,340-pound (610 kg) probe into Didymos' moon at a speed of roughly 14,000 mph (22,500 kph).

It's also crucial to learn more about the materials that dangerous asteroids are comprised of, since their composition may influence how effective we are at deflecting them. Bennu is an asteroid with a diameter of 1,620 feet (490 meters). On Sept. 24, 2182, its orbit will put it perilously close to Earth, with a 1 in 2,700 probability of colliding. Because an asteroid of this magnitude could take out an entire continent, NASA sent the OSIRIS-Rex mission in 2016 to learn more about Bennu. The spacecraft arrived on Bennu in 2023, took photographs, and gathered samples before returning to Earth.

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