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NASA plans to blast “planet killer” asteroids with a 1,000-strong army of spacecraft – or even a nuke.
The space agency boffins have been quietly simulating a response to an out-of-space strike while testing ways to knock a deadly asteroid off course and save the world.
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In 2023, Nasa released the National Preparedness Strategy and Action Plan for Near-Earth Objects and Hazards and Planetary Defence.
The report details how it plans to deal with a Near-Earth Object (NEO) that could spark “global devastation” and suggests blasting them with spaceships or even nukes.
While the doomsday scenario is unlikely with no space rocks posing a risk for the next 100 years, scientists believe thousands of asteroids remain hidden in the solar system.
They predict that dozens of “planet killer” asteroids – over a mile wide and capable of sparking a global extinction event – could be lurking in space.
As part of its disaster plan, Nasa has been experimenting with kinetic impactors – high-speed spacecraft that would ram the giant rock and push it off course.
In September 2022, it tested the method in a $325million mission dubbed the Double Asteroid Redirection Test – or DART.
The speeding rocket “Hera” was successfully launched at a 580ft-wide cluster of rock known as Dimorphos as it orbited the bigger asteroid Didymos.
They posed no threat to the Earth, but the first-ever impact made to alter the course of an asteroid slowed down the pair of space rocks by 30 minutes.
However, the impact risks fragments breaking off and moving in an unpredictable way and may lead to more problems, experts have warned.
To shift a bigger target, roughly 2,000ft-wide or three times the size of Dimorphos, you would need to simultaneously launch nearly 100 rockets.
To deflect a huge “planet killer”, over 1,000 spacecraft would have to be launched from Earth.
GOING NUCLEAR
The second option is a scene straight from the blockbuster film Armageddon – and involves going nuclear.
In the film starring Billy Bob Thornton, the character is sent to space to blow up an Asteroid on course to smash into Earth with a nuclear bomb.
While he buries the bomb into the rock, Nasa would look to detonate the nuke a few hundred feet away, aerospace engineer Brent Barbee told Live Science.
The process would involve attaching the weapon to a launch vehicle and then being delivered to the asteroid by a small spacecraft.
It would then either explode nearby or the spacecraft could orbit the planet-killer rock cluster for months or even years – until a perfect approach point was identified to fire it off course and into oblivion.
A study suggested that to take out a 650ft asteroid you would need a nuclear bomb 200 times more powerful than the ‘Little Boy’ bomb dropped on Hiroshima.
Barbee said: “A single appropriately sized nuclear explosive device was, in our analysis, found to be capable of deflecting even the 1.5-kilometre size asteroid.
“Space, of course, is a vacuum. So you don’t get a big pressure wave or any of the thermal effects of a terrestrial detonation.
“You get a whole lot of radiation all at once.”
The radiation would vaporise the asteroid’s outer layer and any material that shoots off would give the space rock an extra shove and destroy any smaller unpredictable pieces that break off.
In its report, Nasa states: “It is still possible that discovery of either even a relatively small object less than a few months to years before impact or a relatively large or fast-trajectory object would create a situation when only use of a nuclear explosive device (NED) would provide sufficient force to either deflect or disrupt the impactor in time to mitigate devastating effects on Earth.”
A nuclear blast would also be effective at knocking smaller “city-killer” sized asteroids – 165ft wide – off course.
What is most important with both methods is timing as spotting a deadly asteroid that is years away from impact gives scientists more time to intervene.
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Nasa’s Torino Impact Hazard Scale
Explained by Jamie Harris, Assistant Technology and Science Editor at The Sun
Nasa uses something called the Torino Impact Hazard Scale to rate asteroids and other objects.
It goes from zero to 10.
Zero – also known as white zone – is defined as: “The likelihood of a collision is zero, or is so low as to be effectively zero. Also applies to small objects such as meteors and bodies that burn up in the atmosphere as well as infrequent meteorite falls that rarely cause damage.”
Despite being the most dangerous around, the ones listed above are all considered zero.
At the top end of the scale is 10, which states: “A collision is certain, capable of causing global climatic catastrophe that may threaten the future of civilization as we know it, whether impacting land or ocean. Such events occur on average once per 100,000 years, or less often.”
It can take years to develop space missions so chartering and monitoring the skies is crucial, according to Nasa engineer Brent.
“Planet killers” are mostly found in the asteroid belt between Jupiter and Mars while some follow orbits that cross the Earth’s path with the Sun.
They can travel at huge speeds of over 45,000 miles per hour and release catastrophic amounts of kinetic energy.
Immediate effects would see intense heat and debris launched into the atmosphere while global earthquakes, tsunamis and volcanic eruptions would be triggered.
The space rock crash would spark an “impact winter” with sulphur gas, dust and ash blocking out the sun, meaning temperatures would plummet and crops would fail.
The world would be thrown into chaos, with economic collapse, social unrest and conflict.
More than 66 million years ago, the Chicxulub asteroid – the size of a whole city – smashed into Earth and is believed to have wiped out the dinosaur population.
While no known “planet killer” currently poses a threat, astronomers continue to monitor the skies for near-Earth objects and potential collisions.
In April, experts took part in a tabletop exercise at Johns Hopkins Applied Physics Laboratory where a hypothetical asteroid strike played out.
In the simulation, astronomers detect an asteroid with a 72 per cent chance of hitting earth in the next 14 years wiping out Dallas, Washington D.C, Madrid and Algeria and killing 10 million people.
In 2004, an asteroid dubbed Apophis, after the Egyptian god of Chaos, was predicted to fly into Earth’s “danger zone” when it flies past in 2029 and 2036.
Over 1,000ft wide, the space rock is the sized of a cruise liner and could wipe out a whole city if it crashed into planet Earth.
Although it’s now predicted that the asteroid will miss Earth by nearly 20,000 miles, the European Space Agency (ESA) will still be keeping a close eye on Apophis.
The ESA plans to send RAMSES, shot for Rapid Apophis Mission for Space Safety, as part of a mission to study the asteroid closely.
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What’s the difference between an asteroid, meteor and comet?
What’s the difference between an asteroid, meteor and comet?
- Asteroid: An asteroid is a small rocky body that orbits the Sun. Most are found in the asteroid belt (between Mars and Jupiter) but they can be found anywhere (including in a path that can impact Earth)
- Meteoroid: When two asteroids hit each other, the small chunks that break off are called meteoroids
- Meteor: If a meteoroid enters the Earth’s atmosphere, it begins to vapourise and then becomes a meteor. On Earth, it’ll look like a streak of light in the sky, because the rock is burning up
- Meteorite: If a meteoroid doesn’t vapourise completely and survives the trip through Earth’s atmosphere, it can land on the Earth. At that point, it becomes a meteorite
- Comet: Like asteroids, a comet orbits the Sun. However rather than being made mostly of rock, a comet contains lots of ice and gas, which can result in amazing tails forming behind them (thanks to the ice and dust vaporizing)
