Nuclear bombs. Hollywood’s go-to solution for space objects such as comets and asteroids is nukes. Stars such as Bruce Willis deliver nukes to the stars in movies like Deep Impact or Armageddon, which help save the world and provide the drama.
However, planetary defense experts believe that if astronomers spot a potentially dangerous space rock, it might be safer to use a subtler approach, such as simply driving it off course with a small spacecraft.
NASA accomplished exactly that Monday evening when it sent a spacecraft straight into an asteroid and destroyed itself.
Images streamed from the impact showed that the egg-shaped asteroid Dimorphos grew in size as it neared its target. Its full rocky surface was quickly brought into focus as the signal faded.
Engineers had everything planned and nothing went wrong. Elena Adams, mission systems engineer, stated that “as far as we know, our first planetary defence test was a success” and added that scientists watched with “both terror, and joy” as it neared its destination.
NASA’s Double Asteroid Redirection Test, (DART) was the culmination a seven-year effort that cost more than $300 million. It launched a spacecraft in November 2021 to conduct humanity’s first ever test for planetary defense technology.
Scientists estimate that it will take around two months before they can determine if the impact caused the asteroid to drift slightly.
This is not about disruption, but asteroid deflection. Nancy Chabot, DART coordination lead at Johns Hopkins University Applied Physics Laboratory said earlier that this is not going to destroy the asteroid. She said that the collision is a slight nudge, similar to “running your golf cart into the Great Pyramid.”
Modifying the orbit of a space rock
Dimorphos lies approximately 7 million miles from Earth and is not a threat to Earth. It measures 525 feet in diameter and orbits an even larger asteroid.
NASA officials stated that neither of the space rocks could have been considered a threat by their tests.
Thomas Zurbuchen is an associate administrator at NASA’s science mission directorate. He says, “There are no circumstances in which one body could become a threat for the Earth.” “It’s scientifically impossible, thanks to momentum conservation and other factors.”
The impact will reduce the time required for Dimorphos orbiting its larger asteroid pal. A full circuit currently takes 11 hours 55 minutes. The DART impact will change Dimorphos’ path so it is closer to the big Asteroid and takes less time. It may do this once every 11 hours and 45 mins.
These two asteroids can be seen from so far away that telescopes view them as one point of light. It dims and shines as Dimorphos moves around. Scientists had never had the chance to see the asteroid that they were trying to find with the DART spacecraft’s camera.
Initial targets were made by the spacecraft’s onboard navigation system, which initially focused on the larger and more easily-spotted asteroid. However, they switched their focus to Dimorphos during the final hour of the mission.
NASA lost the ability of sending commands to the spacecraft in the last minutes of impact at 14,000 mph. Scientists simply waited and watched. As the screen turned red due to loss of signal, there was a roar of laughter in the control room.
A smaller spacecraft was nearby and sent images back to Earth in the days that followed. The collision will be observed by telescopes from all seven continents and space telescopes such as James Webb for several weeks. This will allow astronomers to precisely measure the path of the asteroid.
In a few years, the European Space Agency (ESA) will send Hera, a mission to the double asteroid system. This mission will allow scientists to gather more information about the impact’s effects.
This should show how an asteroid reacts when it is pushed. Scientists can use this information to make contingency plans for possible future threats.
“The bottom line, it’s great,” Ed Lu, executive director of The Asteroid Institute, an organization dedicated to planetary defense, says. “Someday we will find an asteroid with a high chance of hitting Earth and we will want to deflect it,” says Ed Lu.
Lu says that when that happens, it is important to have some prior experience so that you know that it will work.
Many asteroids are still to be discovered and tracked.
The DART mission team seems to be able to see that the project sounds a bit far-fetched.
“We are moving an asteroid. We’re changing the motion of a celestial body that is naturally occurring in space. “Humanity has never done this before,” states Tom Statler, NASA’s DART scientist. This is science fiction stuff and really silly episodes of Star Trek that I remember reading about, but it’s now real. It’s amazing that we’re actually doing this, and how that bodes well for the future of our possibilities.
NASA monitors many space rocks, particularly the larger ones that could lead to extinction-level events. None of these space rocks currently pose a threat to Earth. However, many asteroids larger than Dimorphos have not been found and could possibly destroy a city if it crashed.
NASA’s Planetary Defense Coordination Office is aiming to launch NEO Surveyor, an asteroid-hunting space telescope. It could be launched in 2026 or 2028 depending on how much Congress spends.
“It’s something we have to do so that we know where it is and what’s coming, and have sufficient time to prepare for them,” Lindley Johnson, NASA’s Planetary Defence Officer.
He believes such a telescope could provide Earthlings with years, decades, or even centuries worth of warnings about space rocks on alarming paths — enough time to find a solution.
Johnson notes that all of this is quite different to the Hollywood version of saving the planet.
He says, “They need to make it exciting. You know, we find an asteroid 18 days before it hits and everyone runs around with their hair in fire.” “That is not how you do planetary defense.”