The asteroid 2024 YR4, once considered potentially hazardous, isn’t likely to hit us anytime soon. Now, a team of researchers says that instead of stressing about the near miss, we can be excited by it because it will give us a surprising opportunity to study the asteroid up close.
2024 YR4 was first discovered in December 2024. It’s relatively small — just 130 to 300 feet (40 to 90 meters) across. But it’s classified as an Apollo-type asteroid, meaning its orbit regularly intersects that of Earth, thus creating the potential for an impact. When 2024 YR4 was first observed, astronomers estimated that it had a roughly 1% chance of striking us.
As observations improved, the chance of an encounter went up to a few percent, which triggered panicked headlines around the world, as an impact of that size would release an energy equivalent to nuclear warhead yields. If it struck a major city, the damage would be incalculable. But even more refined calculations have now brought that chance down to nearly zero, so we can all breathe a sigh of relief.
But when the universe gives you asteroid lemons, you should make science lemonade, researchers at the Initiative for Interstellar Studies in the United Kingdom and Space Initiatives Inc propose in a paper uploaded to the preprint database arXiv in February.
They pointed out that, even though 2024 YR4 likely won’t strike Earth, it will come close on a regular basis. This makes it an excellent target for future asteroid missions. The asteroid will make close passes roughly every four years, when its orbit crosses Earth’s. This means that, during those windows, the asteroid and our planet don’t have very large differences in velocities. When that happens, once a spacecraft has left Earth’s gravity well, it can reach the asteroid essentially “for free”; it doesn’t need that much extra velocity.
The researchers estimated that fly-by missions are exceptionally easy, with launch windows opening up almost every year. In 2028, a mission could reach 2024 YR4 in as little as a few months and pass by it very slowly, providing plenty of time for detailed observations.
But even more complicated missions are well within the capabilities of our current technologies. If we wanted to perform a repeat of NASA’s DART mission, which successfully deflected a small asteroid, we could test that with 2024 YR4.
The researchers found that if we launched such a mission during an optimal window, around the summer of 2028, a spacecraft weighing as little as 22 pounds (10 kilograms) could reach the asteroid in a few months, strike it and change the asteroid’s path by up to 620 miles (1,000 km). This would mean that if 2024 YR4 were going to hit Earth on its next closest approach in 2032, we could nudge it enough to avoid disaster.
Even rendezvous and landing missions are relatively easy. A launch in December 2028 could bring a spacecraft to the asteroid with enough fuel left over to rendezvous with it and attempt a landing, the research team said. The time between launch and landing would be only a couple of years, so we could deploy the latest technology and know that it would be sitting on an asteroid’s surface in a very short time. That mission could also collect samples and bring them back to Earth for further study.
In fact, the researchers noted that we already have the technology to accomplish all of this. A spacecraft like New Horizons, which sped off to the outer limits of the solar system in 2006, has more than enough capabilities to study 2024 YR4 in as much detail as we want during its next closest approach.
So the next time we hear about a potentially hazardous asteroid, we should instead hope that it comes close enough that we can get some good science out of the encounter.
