ESA's Hera Mission Examines Asteroids Didymos and Dimorphos After NASA's Intentional Impact

The possibility of preventing a dangerous asteroid from colliding with Earth using a nuclear explosion exists, but the success of this strategy critically depends on one unexpected factor: the side of the celestial object exposed to radiation. A new study showed that the incorrect shape of these heavenly bodies directly affects the maneuver's effectiveness.

The research, published in the scientific journal Icarus, was conducted by scientists from the Sandia National Laboratories in the United States. Using computer modeling, the team demonstrated that irradiating different parts of the same asteroid can lead to completely different results in its trajectory and rotation.

A difference of almost five times in the deflection speed of the same object was identified, which depended on the angle of the explosion. In one simulated scenario, the change in speed was 3.9 millimeters per second in one direction, but only 0.8 millimeters per second in another.

For another analyzed asteroid, the change in rotational speed varied by 17 times depending on the impact location.

The strategy under consideration is not simply destroying the celestial body. The idea is to cause a nuclear explosion at a certain distance, causing the X-rays released by the blast to reach part of the asteroid's surface. The radiation intensely heats the surface material, causing it to evaporate. The ejected material acts as a kind of engine, creating an impulse capable of changing the object's movement.

Modeling allows for tuning parameters such as the size and distance of the explosion, as well as the area receiving radiation. Based on this data, the program calculates how much material will evaporate, what impulse will be created, and how the asteroid's rotation will change. Furthermore, researchers can estimate the pressure exerted on different parts of the surface and determine the risk of material fragmentation.

The last aspect is particularly important. The goal of planetary defense is to deflect the asteroid, not to destroy it into smaller pieces that could still pose a threat to Earth. Despite promising results, the tool still has limitations. Currently, the model accounts for the fragmentation of surface rocks but cannot accurately predict the rupture of the entire asteroid body.

Scientists also emphasized that high-resolution three-dimensional images of the object, containing information about its shape from all sides, are necessary for operation. In a real emergency, there may not be enough time to collect such data. Another problem is placing the explosive device at the optimal distance and in the correct direction while the asteroid is moving in space.

Despite these difficulties, this study represents progress in preparing for potential cosmic threats. This tool can help calculate the most suitable intensity, distance, and direction of a nuclear explosion, thereby increasing the chances of deflecting a dangerous object before it reaches our planet.

Research conducted by the University of Cambridge suggests that it is highly unlikely for a comet to deliver large volumes of intact molecules to the Earth's surface. This finding casts doubt on an old theory regarding the genesis of life, although it does not rule out other ways these celestial bodies might have contributed.

The study, published in the journal Scientific Reports, focused on analyzing the transport of hydrogen cyanide (HCN), a substance crucial for the chemical reactions that could have preceded the emergence of life.

Historically, comets were viewed as potential sources of raw material for prebiotic chemistry because they carry organic molecules. However, the arrival of these compounds on the Earth's surface depends on very specific circumstances.

The simulations performed indicated that comets frequently struck Earth at high speeds and with excessively inclined angles. The heat and pressure resulting from these collisions could destroy HCN before it reached the soil in an intact state.

Furthermore, even if the molecule survived the impact, its concentration would need to be high enough to drive the investigated chemical reactions. Dilution in the aquatic environment could also decrease the time required for such processes to occur.

Richard Anslow, a researcher at the University of Cambridge Astronomy Institute and the lead author of the work, admitted that the hypothesis cannot be entirely dismissed. He stated that while possible, it would appear to be an extremely rare event, perhaps an isolated coincidence.

The situation becomes even more complex when considering that the rate of comet impacts decreased drastically during the first five hundred million years of Earth's history, thus limiting the chances of delivering significant amounts of HCN.

It is important to note that the research addresses only one specific mechanism and does not determine whether comets had other forms of participation in the early life. There are other viable explanations for the presence of the chemical components necessary for the first reactions, and these were not excluded by the study, as it did not exhaustively evaluate all organic molecules or all chemical consequences of the impacts.

The simulations suggested that Mars would present more favorable conditions for receiving prebiotic molecules brought by comets. Due to its smaller size than Earth and its thinner atmosphere, the planet would offer fewer barriers to the arrival of these compounds during periods of higher impact incidence.

This result does not imply that life originated on Mars; it refers solely to the possibility of transporting chemical inputs, without determining whether these gave rise to living beings.

Additionally, the study may aid in guiding the search for life on other planetary systems, as identifying systems where comets transit between planets is a tactic that can enrich future astronomical observations.

In summary, the research restricts one of the proposed theories for the origin of life on Earth, keeping open the fundamental question of how chemical elements organized themselves to enable the emergence of the first organisms.

When imagining future space travel, such as a direct flight to Mars, a silent and dangerous risk emerges: solar storms. Millions of kilometers from Earth, a large amount of energetic particles can pass through space toward the spacecraft, posing a serious health risk to the occupants, even without visible signs like smoke or explosion.

This fundamental challenge of long space missions lies in how to safeguard astronauts against this invisible threat. Tiny particles, smaller than an atom, have the potential to cause significant damage to human health.

On Earth, protection is guaranteed by the atmosphere, which absorbs much of the radiation, and by the Earth's magnetic field, which deflects many charged particles. However, when we move away from this natural defense, these particles can strike the crew directly, potentially causing acute effects or increasing the risk of cancer and other long-term illnesses.

There are two main types of radiation to consider. The first consists of energetic particles emitted by the Sun, especially during intense solar flares and storms, which can expose astronauts to dangerous doses in short periods. The second challenge is galactic cosmic rays, high-energy particles originating from outside the Solar System, some of which are atomic nuclei traveling almost at the speed of light, making them particularly difficult to block.

To protect future space explorers, hydrogen, the lightest atom, emerges as a crucial ally. It is highly effective in reducing the energy of certain harmful particles, such as high-energy protons and ions present in cosmic rays. Thus, materials like water and hydrogen-rich polymers can be used to protect astronauts.

A promising approach involves using materials already aboard the spacecraft. Water tanks, for example, can be placed around the areas inhabited by the crew, just as food and equipment can be strategically distributed to reinforce shielding.

A test conducted on the International Space Station demonstrated that a barrier composed of hydrated materials, with a thickness equivalent to about six centimeters of pure water, managed to reduce the equivalent radiation dose measured by researchers by approximately 37%. However, it is observed that simply increasing the thickness of the shielding does not always result in a proportional increase in protection, as the collision of more potent cosmic rays with the shielding can generate secondary particles, requiring more than just surrounding the ship with water.

Research is also exploring the conversion of plastic waste into shielding materials. Instead of discarding packaging, a future mission could recycle it to create protective parts. Furthermore, scientists are studying water-based materials, such as 3D-printed hydrogels, envisioning astronauts protected by a gelatinous substance.

Another vital measure is establishing a shelter against solar storms. The idea is to designate a section of the spacecraft that can be surrounded by water, supplies, and other protective materials. Upon detecting a dangerous solar event, astronauts would take refuge in this compartment until the situation improved.

Specialized protective clothing, such as the AstroRad vest, developed to mitigate bodily exposure to specific energetic particles, is also being tested. Experiments conducted during Artemis I, during the flight around the Moon, helped assess the effectiveness of this equipment, although a vest does not replace spacecraft shielding, and solutions must balance protection, weight, and mobility.

Considering the possibility of deflecting radiation, magnetic shielding arises. Since many dangerous particles carry an electric charge, intense magnetic fields could alter their trajectories, diverting them away from the astronauts, following the principle of the Earth's magnetic shield. The obstacle lies in replicating this on a spacecraft, requiring complex systems with superconducting magnets that generate strong fields without adding mass or consuming excessive energy; research is advancing, but a compact and reliable shield is still distant.

A more radical proposal suggests not using shielding, but rather utilizing the protection of a celestial body by installing a shelter inside an asteroid. The rock itself would serve as a natural barrier. Although physically grounded, the application is extremely complex, requiring finding a suitable asteroid, reaching it, constructing an internal shelter, and transforming it into a type of orbital space shuttle, not to mention that secondary cosmic ray particles could still pose a risk even under thick rock.

It is concluded that no single solution solves the problem; protection in the first interplanetary journeys will likely require a combination of appropriate materials, continuous monitoring, shelters for solar events, and, in the future, radiation deflection technologies.

Although many wish to leave the planet quickly, space radiation represents a greater health risk than terrestrial political disputes. While scientists seek safe methods to explore space, it becomes essential to solve the problems on the known planet, which offers all the necessary conditions to sustain life and peace.