Mars May Face Higher Risk of Close Encounters With Potentially Dangerous Asteroids; How Can It Affect Exploratory Missions to the Red Planet?

Potentially hazardous asteroids could pose a threat to Mars missions, although they can also provide insights into the formation of the inner solar system.

Threats From Space Rocks

Asteroids are considered the biggest threat to our planet from space. For instance, the 2013 Chelyabinsk meteor produced shock waves that injured more than 1,000 people and resulted in over $33 million in damage to infrastructure.

Experts and citizen asteroid hunters have spotted almost 33,000 similar cosmic objects that approach closely past our planet during their journey around the Sun. Some of them are huge and measure 460 feet (140 meters) in diameter. They also approach the orbit of the Earth at distances of less than 4.6 million miles (7.4 million kilometers).

These space rocks are called potentially hazardous asteroids (PHAs). Astronomers track these objects because they serve as key components of planetary defense programs during space missions.

Mars may have it worse since it is located right next to the main asteroid belt, a region in the Solar System between the orbits of Mars and Jupiter where many asteroids are found. However, the number of asteroids that approach Mars is not clear, and it could pose some problems since the Red Planet hosts many space missions and may be home to human colonies in the future.

Understanding Mars-CAPHAs

At Nanjing University in China, a team of researchers tested whether humans on Mars would be more at risk of hazardous asteroid impacts. Led by Yufan Fane Zhou, the team analyzed how the Red Planet closely encounters these space rocks, which they called "close approach potentially hazardous asteroids (CAPHAs)."

The scientists determined the number of Mars CAPHAs by using computer models to simulate the motion of all eight planets and 11,000 chosen asteroids over 100 million years. All of these space rocks began in the main asteroid belt, and 10,000 of them were classified as "near-gap." This classification is based on their proximity to six known asteroid-poor zones within the main asteroid belt where runaway rocks can possibly slip out.

During the computer simulations, Zhou and colleagues made the near-gap asteroids drift toward or away from the Sun. Such drift arises because of the Yarkovsky effect, a kind of force that is generated when the sunlit part of asteroids re-radiate the heat they receive and behave like mini-thrusters.

It was revealed that every Earth year, around 52 huge asteroids travel dangerously close to Mars, almost 2.6 times those that approach Earth annually. But while these space rocks come closer to the Red Planet than the CAPHAs do to Earth, they also travel more slowly.

The researchers are uncertain as to whether near-Mars objects may affect our current space missions. As human visits to the Red Planet become more frequent in the future, the dangers from Mars-CAPHAs may be increasingly taken more seriously.

Aside from this, Mars-CAPHAs can also be informative for experts. According to Zhou, these space rocks around Mars can deepen our understanding of the Martian environment, the interactions between planets and asteroids, and the evolutionary history of the inner solar system.