Oldest Mars Meteorite Points to Earth-like Environment

The Perseverance rover, operated by NASA, identified dust particles on the surface of Mars with dimensions of approximately 100 nanometers, making them about 500 times finer than a human hair. This finding raises concerns about the risks this material poses to the health of future astronauts and to the preservation of habitats and spacesuits during crewed missions to the planet.

The detection was made using the PIXL instrument, which analyzed particles accumulated on the rover's equipment and in samples of transported materials. In addition to the ultrafine 100-nanometer particles, the instrument also detected particles with a diameter smaller than 2.5 micrometers.

Such minuscule particles have the ability to penetrate deep into the lungs and reach the bloodstream, potentially causing damage to vital organs. However, according to Scott VanBommel, a planetary scientist at the University of Washington in St. Louis and lead author of the study published in the Proceedings of the National Academy of Sciences, the level of risk is directly linked to the quantity and duration of exposure.

The chemical composition of the Martian dust is also a point of concern, as it contains silica, iron compounds, and chlorine compounds, such as perchlorate, substances that can be harmful in high concentrations.

To investigate how the dust adheres to potential materials for spacesuits, Perseverance carries samples of two types of material: the synthetic fiber Vectran and a protective Teflon coating, both measuring about 20 millimeters on a side. The results of these tests indicated different behaviors; VanBommel emphasized that the tests did not show damage caused by the dust to these materials, suggesting that the observed variations may stem from the physical-electrostatic characteristics of each, affecting particle adhesion.

Additionally, the dust has the potential to deteriorate habitat and spacesuit materials over time. The data collected by the rover are crucial for guiding the selection of appropriate materials and for developing efficient cleaning procedures capable of removing particles smaller than one micrometer.

NASA already has knowledge about the effects of dust on space missions, dating back to the Apollo lunar landings between 1969 and 1972. On the Moon, the material caused wear on the outer layers of suits, damaged seals, and scratched visors, and could also contribute to symptoms similar to hay fever in some astronauts. Lunar dust is primarily formed by surface impacts and remains angular and sharp due to the absence of an atmosphere or wind to wear it down. In contrast, on Mars, the biggest concerns lie in the chemical composition and the reduced size of the particles.

With NASA planning to send astronauts to the Red Planet as early as the 2030s, VanBommel stated that the findings will serve as a basis for guiding the planning of life support systems, the selection of materials for suits and habitats, and the creation of protocols to manage toxicological risks. The researcher concluded that such findings will aid in designing future human support systems for Martian missions, covering material selection and the establishment of effective cleaning methods for sub-micrometer particles.

The search for signs of life on Mars partially depends on analyses that can only be conducted with high accuracy on Earth. Samples collected by the NASA rover Perseverance are stored in tubes on the surface of the Red Planet. However, their return involves technological difficulties, high costs, and strict protocols to prevent contamination of the material and protect the Earth's biosphere.

The initial plan of the Mars Sample Return mission, developed by NASA in collaboration with the European Space Agency (ESA), involved collecting the tubes left by Perseverance and delivering them to a lander. Alternatively, two helicopters equipped with robotic manipulators could retrieve samples directly from the surface. A small rocket would launch a capsule containing the material into Martian orbit, from where a European spacecraft would capture and transport it to Earth. The delivery was initially planned for 2033.

Nevertheless, the project has faced technical problems, delays, and rising costs. Due to these obstacles, NASA suspended the original mission architecture and began evaluating more economical options, including proposals from the private sector. As a result, the return schedule has been revised and now depends on determining a new strategy.

While the United States reviews its plans, China is developing the Tianwen-3 mission, which aims to bring Martian material to Earth by 2031. The China National Space Administration (CNSA) intends to collect and return samples using its own technologies. If schedules are met, the country could deliver material from Mars earlier than the American-European mission.

Concerns about sample return are not limited to the possibility of discovering signs of life. Scientists must also ensure that the material is not contaminated during transport and that its arrival on Earth does not pose biological risks.

The planetary protection policy of the Committee on Space Research (COSPAR) establishes international guidelines for reducing contamination between Earth and other celestial bodies. One of the issues is so-called forward contamination, which occurs when terrestrial organisms are transferred to extraterrestrial environments. The reverse process, known as back contamination, involves the possibility that extraterrestrial material could introduce organisms or biological agents to Earth.

In the case of Mars, the hypothesis of microorganisms capable of surviving the journey and causing consequences for the Earth's biosphere must be considered in safety protocols, but there is no evidence of Martian life in the samples. Biological risk should not be confused with a confirmed threat to human health.

In an interview with Olhar Digital, astrobiologist and professor of geobiology at the Institute of Geosciences of the University of São Paulo (USP), Douglas Galante, stated that he considers the risk of any Martian organism posing a biological threat to Earth to be very low. In his opinion, there is no reason to panic, although the possibility of ecological consequences requires a scientifically rigorous approach.

This week, the highlights in Science and Space on Olhar Digital included the NASA rover that set a new distance record on Mars, the SpaceX Starship rocket returning to the ground base after navigating the ocean, and the Moon moving away from Earth.

The Perseverance rover, belonging to NASA, registered a new milestone in distance traveled on Mars, exceeding 45.2 km since its arrival on the planet in February 2021. This achievement was reached on the 11th in the Jezero crater area and was communicated by the Jet Propulsion Laboratory (JPL) on Monday, the 12th, which is the agency responsible for managing the vehicle.

With this performance, the robot surpassed the total mileage recorded by Opportunity, another NASA rover that explored Mars between 2004 and 2018. However, the progress of Perseverance did not occur as initially planned, as the team had to change course to investigate light rocks, which may be some of the oldest studied on the planet, resulting in a delay of about two months in achieving the record.

Meanwhile, SpaceX transported the Ship 40 back to Texas, in the United States. This was the first Starship to survive an ocean landing after a space journey. The vehicle arrived at the company's base almost three months after its launch and will undergo a detailed analysis by engineers.

This inspection aims to evaluate the components subjected to the severe conditions of atmospheric reentry. The collected data may assist the company in developing a Starship capable of returning to base and conducting new flights.

Ship 40 was launched on July 24, coupled with the Super Heavy Booster 20, during the 13th test flight of Starship. The mission culminated in a controlled landing in the Indian Ocean. In previous tests, other ships had exploded after falling into the water, but Ship 40 remained practically intact and buoyant, leading SpaceX to decide to rescue it despite the complexities of an open-sea operation.

Two issues related to the Moon were highlighted this week. One concerns a study suggesting that it is undergoing a process of 'shrinking,' a phenomenon that is intensifying 'lunamotes' (moonquakes) and affecting the surface of the natural satellite. According to the research, this process occurs slowly: over the last 400 to 800 million years, the lunar radius has decreased by approximately 45 meters.

Additionally, the Moon reached its apogee this Friday, the 16th. This means it reached the farthest point from Earth in its current orbital trajectory. It is observed that this distance tends to increase progressively, and one possible consequence of this increase is the disappearance of total solar eclipses.