On November 19, the International Space Station (ISS) adjusted its orbit to avoid a fragment of space debris originating from a satellite that disintegrated in 2015, according to NASA reports. The maneuver raised the station’s altitude of approximately 250 miles (440 kilometres) above Earth, preventing the debris from coming within 2.5 miles (4 kilometres) of the orbital outpost. This marked the 39th avoidance action taken by the ISS since its initial launch in November 1998 and the first instance of 2024.

Space Debris: A Growing Threat

Data from NASA shows that over the years, the ISS has conducted multiple maneuvers annually to protect its crew and infrastructure from space debris, although 2024 has seen fewer incidents compared to previous years. Hugh Lewis, a professor of astronautics at the University of Southampton, explained in Live Science that while fewer evasive actions have been needed so far this year, this could change unpredictably, with sudden increases in collision risks potentially necessitating immediate responses.

Causes of Space Junk Proliferation

According to reports, increased solar activity during the current solar maximum cycle has been influencing the behaviour of space debris. Solar events, such as coronal mass ejections, cause Earth’s atmosphere to expand, creating drag that can alter debris trajectories. Additionally, deliberate satellite destruction tests, such as Russia’s anti-satellite (ASAT) test in 2021, have significantly contributed to the accumulation of hazardous debris. Four of the nine maneuvers conducted by the ISS since 2021 were linked to fragments from Cosmos-1408, a Soviet-era satellite targeted during the ASAT operation.

Mitigating Future Risks

Experts, including Lewis, have emphasised the importance of removing defunct satellites to limit debris growth. It was noted that proactive measures, such as deorbiting retired satellites, would reduce collision threats significantly. With the ISS scheduled for decommissioning in 2031, maintaining safe operations remains critical as the threat from space junk continues to escalate.

Planetary scientists have explored a hypothetical scenario in which a super-Earth existed within our solar system, situated between the orbits of Mars and Jupiter. According to recent simulations conducted by Emily Simpson and Howard Chen, planetary scientists at the Florida Institute of Technology, such a planetary configuration could have drastically destabilised the climates and orbits of neighbouring planets, including Earth.

Gravitational Instability and Climate Disruption

The findings, as per a Space.com report, highlight that super-Earths, which are commonly observed in exoplanetary systems, are notably absent from our solar system. These planets, larger than Earth but smaller than Neptune, are a frequent occurrence in the Milky Way. The researchers simulated various iterations of a super-Earth within our solar system to assess its gravitational effects on inner rocky planets like Earth, Venus, and Mars.

The study is said to have revealed that the presence of a super-Earth, particularly one with a mass ranging from 10 to 20 times that of Earth, would have caused significant disruptions. Chen stated in his interview with Space.com that the gravitational pull of such a planet could push smaller rocky planets into eccentric orbits or tilt their trajectories. These unstable orbits would lead to extreme climatic conditions, including erratic transitions between ice ages and periods of intense warming.

Chen told the publication that while the configuration we observe in our solar system is uncommon, the presence of a super-Earth in this region could have made Earth’s orbit highly unstable, jeopardising its habitability.

Implications for Life in Exoplanetary Systems

The findings suggest that even planets located in the habitable zones of other star systems may face significant challenges to sustaining life if they share their region with massive super-Earths. The instability introduced by such neighbours could hinder the evolutionary processes that require relative climatic stability.

While a slightly larger planet near Mars might lead to harsher seasonal variations on Earth, conditions for life could still persist. However, the researchers emphasised that the absence of a super-Earth near Mars and Jupiter may have been critical in enabling Earth’s current hospitable environment.

Efforts to uncover life on icy moons within our solar system have been bolstered by advancements in chemical modelling, according to recent reports. These models are being refined to better assess whether environments like Saturn’s moon, Enceladus or Jupiter’s moon Europa could support microbial life. Researchers aim to simulate the extreme conditions found on these celestial bodies to determine their potential habitability.

As outlined in the press release by Southwest Research Institute, Charity Phillips-Lander, Senior Research Scientist at Southwest Research Institute (SwRI), has emphasised the importance of accounting for organic compounds in such studies. Existing geochemical modelling tools often lack the capability to incorporate organics under the unique conditions of icy ocean worlds. Speaking to Space.com, Phillips-Lander stated that the question of habitability is about constraining the environmental factors that make it more likely to be friendly to life versus inhospitable.

Phillips-Lander and colleague Florent Bocher have developed custom software to simulate the formation and behaviour of organic-doped ice pores—microscopic structures formed under freezing and thawing conditions.

These phenomena, observed in laboratory analogues, are being used to replicate environments found on moons like Enceladus. The software’s ability to predict the interactions of organic compounds with ice under extreme temperatures and pressures provides key insights into potential microbial habitats.

According to the report, the team is focused on refining the tool to accurately model the chemical processes occurring in subsurface oceans beneath thick ice crusts. Enceladus is of particular interest due to its suspected water-rich environment and active plumes, which could indicate the presence of organic molecules.

Implications for Future Missions

The researchers have indicated that the refined models could serve as very important tools for interpreting data from future missions targeting icy moons. Phillips-Lander explained that the project aims to fill gaps in current datasets, enabling more accurate laboratory simulations and aiding in the identification of potential biosignatures.

Reports suggest that these efforts are expected to contribute significantly to understanding the habitability of icy worlds and support ongoing explorations of potential extraterrestrial life.