Greatly disappointed, to the relief of all those who keep an eye on the skies, the massive object was not an asteroid.
ESA's Juice Spacecraft Confused with a Threatening Asteroid
On July 6, the European Space Agency (ESA) received an alarming message from the automated systems that constantly scan the skies for hazardous space objects.
The object was large, approximately 164 feet (49.99 m) in diameter, and speeding toward Earth on a trajectory that would take it dangerously close to both the Moon and our planet. Yet, to the relief of everyone monitoring the skies, the massive object wasn’t an asteroid. It was actually ESA's own juice spacecraft.
ESA's automated alert system had initially categorized the object as a potential threat. The object’s brightness and size suggested a large asteroid. Follow-up observations, however, revealed that this mysterious body wasn’t a threatening space rock.
It was the Jupiter Icy Moons Explorer (Juice), a probe on a mission to study Jupiter's icy moons. The spacecraft was passing Earth to utilize a gravitational slingshot to propel itself deeper into the solar system.
While juice isn't nearly as large as the automated systems had first estimated, it’s still a substantial craft. Its impressive solar panel wings stretch 88 feet (26.82 m) across, creating a bright signature in space that led to confusion. ESA’s alert system had detected this reflection and overestimated its size, mistakenly labelling it as a menacing asteroid.
Is it an asteroid? Is it a comet? No! It’s @ESA_JUICE! Juice was briefly mistaken for a new potentially hazardous asteroid as it races towards Earth for next week’s double flyby. Fortunately, experts have confirmed that Juice poses no risk to our planet😉https://t.co/lGMBfT4hHA pic.twitter.com/FaDjKTPBmh
— ESA Operations (@esaoperations) August 15, 2024
Scanning the Skies for Threats
Modern sky surveillance systems, like NASA's Asteroid Terrestrial-impact Last Alert System (ATLAS), are designed to detect potentially dangerous objects well before they approach Earth. Identifying threats is crucial for early preparation, and in the worst-case scenario, it could give humanity time to react or even evacuate areas in danger.
As Eric Christensen, director of the Catalina Sky Survey, emphasizes: “You need to know what's coming, when it's coming, and how hard it's going to hit.” Fortunately, such threats are rare, and current monitoring indicates that there are no known asteroids on a collision course with Earth for the next 100 years, according to ESA.
The Real Risks From Space Rocks
However, while the Juice spacecraft posed no danger, asteroids and space debris continue to pose real risks. Earth is constantly bombarded by space material, though most are harmless. For instance, around 100 tons of dust and sand-sized particles enter Earth's atmosphere daily, burning up upon entry.
More concerning are the rare but impactful events, like the 2013 Chelyabinsk event in Russia. A surprise asteroid, just 56 feet (17.07 m) wide, exploded in the sky, damaging buildings and injuring hundreds.
Larger rocks, measuring 460 feet (0.14 km) across, strike Earth every 10,000 to 20,000 years, while catastrophic impacts, like those that wiped out the dinosaurs, occur only every 100 million years.
Though the odds of a major impact are slim, space agencies continue their vigilant watch, knowing that even smaller rocks can cause significant damage.
The Juice false alarm is a reminder of how crucial this work is—whether it’s identifying a potential hazard or simply monitoring our spacecraft as they journey beyond Earth.