On July 4, 1997, NASA’s Pathfinder mission sent the Sojourner rover on a journey of 120 million miles, lasting 7 months, to Mars. Nearly 30 years have passed, yet why have we not brought soil samples from Mars back to Earth?
In the past, many scientists proposed banning the collection of soil from alien planets, as these soils could harbor deadly viruses. Various theories suggest that exposure to Earth’s environment could bring numerous disasters to humanity and the planet.
However, humans have successfully collected over 380 kg of soil from the Moon and returned it to Earth. Through extensive research and evaluation of this lunar soil, scientists have confirmed that there are no so-called harmful substances, such as bacteria or viruses, in lunar soil.
Humans have collected over 380 kg of soil from the Moon and returned it to Earth.
The most recent collection of lunar soil was during the Chang’e-5 mission (or Chang’e 5), a robotic mission under China’s lunar exploration program in 2020.
During the ceremony to unseal the lunar soil from Chang’e-5, it was evident that the personnel were not wearing strict protective clothing. This does not imply that the lunar exploration program was unprepared; rather, it subtly confirms that lunar soil is not “dangerous,” meaning it does not contain any harmful substances, let alone deadly viruses.
The ceremony to unseal the lunar soil from Chang’e-5.
In fact, the Moon has been explored by humans for decades, dating back to the space race between the United States and the former Soviet Union, which brought back over 380 kg of lunar rock and soil—of which the Soviet Union returned over 300 grams, and the United States returned approximately 382 kg. In recent years, only China has brought back 1,731 grams of lunar soil, and no other country has returned additional lunar soil since then.
In terms of quantity, the lunar soil collected by humans is not large and is only sufficient for scientific research. After studies, it has been found that lunar soil is very safe and non-toxic.
Lunar soil collected by humans is not abundant and is only sufficient for scientific research.
First of all, the Moon is Earth’s satellite, and there are various opinions regarding its origin. Some believe it is the remnant of a foreign planet, while others think it is part of Earth. After years of exploration and research on lunar soil, it has been found that most lunar soil is mineral-based, showing no signs of life, let alone organic matter. Thus, lunar soil is not only non-toxic but also unsuitable for agriculture.
If lunar soil were to contain viruses, the first premise would be that the Moon must have an environment where viruses could survive. The Moon is a natural satellite with no magnetic field or atmosphere and cannot stabilize naturally. The Sun and other high-energy particles from space continuously bombard the Moon’s surface, leading to a lack of water, air, and very low gravity…
In such an environment, based on current human knowledge, it is certain that there can be no life or viruses existing on the Moon. Therefore, the Moon, as a nearby and relatively safe planet, may serve as the first stop for humans venturing into deep space.
Mars and the Moon are not the same; Mars is more similar to Earth.
However, Mars is a different story. Mars and the Moon are not the same; Mars is more similar to Earth. There is evidence that 3 billion years ago, Mars was a planet akin to Earth, with an atmosphere and oxygen, providing a perfect environment for life, and its surface was once covered by oceans. Subsequently, due to significant changes, Mars lost its atmospheric protection and gradually became the planet we see today.
Even after many years, there may still exist some faint forms of life on the surface of Mars that we have yet to discover. In fact, this planet still shows traces of a magnetic field at its northern and southern poles, and astronomers have also found water existing in the form of solid ice at the northern pole of Mars.
Moreover, scientists also believe that the soil on Mars is rich in organic material, which could be used for agriculture. Based on this, researchers have conducted related experiments by simulating the Martian environment and then planting seeds in the soil. The results show that the seeds can germinate, grow, and develop. This experiment provides some support for the potential migration of humans to Mars.
However, this also suggests that the surface environment of Mars may be a habitat for viruses, so the likelihood of viruses existing in Martian soil is entirely plausible.
As for why, at this moment, after nearly 30 approaches to Mars, we still cannot bring Martian soil back to Earth, the answer is simply that the time is not right. Currently, NASA is still searching for ways to bring Martian rock and material samples back to Earth to enable scientists to directly study the composition of the soil and rocks on the Red Planet and search for potential life forms if they exist.
Currently, NASA is still searching for ways to bring Martian rock and material samples back to Earth.
The plan for this mission is to send two spacecraft to Mars in 2026. One spacecraft will land in the Jezero Crater and send a rover to rendezvous with the Perseverance rover to collect sample tubes.
Afterward, this rover will return to deliver the samples to the spacecraft in the Jezero Crater. This spacecraft will launch and enter orbit around Mars. From there, a second spacecraft will be launched to connect with this spacecraft to retrieve the sample tubes and bring them back to Earth.
In reality, the plan to retrieve Martian soil samples will take a long time to execute, as this planet is much farther from us than the Moon, and achieving this will also require significantly more funding. As for whether Martian soil contains organic material or viruses, we will need to wait for the samples to be brought back to Earth before we can confirm anything.
This is a perfectly normal concern, as anything unknown can cause fear among people. For example, when lunar soil samples were first collected, humans wore thick protective suits to guard against potential radiation or toxic substances.
Over time, as understanding of the Moon deepened, people have ceased to fear lunar soil. Similarly, when handling Martian samples, we will certainly be equipped with adequate protective gear and research equipment, and after thorough investigations, all questions regarding Martian soil will be resolved.
