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Small solar system bodies (SSSBs), which, in this study, are defined primarily as asteroids and comets, are becoming increasingly important as more data have become available for their study. Their significance is also highlighted by missions such as NASA's "Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer" (OSIRIS-REx), or ESA's Rosetta. However, the study of the characteristics and behavior of these objects on Earth is a challenge, as the simulation of their environmental conditions is difficult. We present in this paper an approach to enable the gravity simulation of SSSBs, such as comets or asteroids, in a drop tower facility on Earth, which is being addressed as part of the AKUS ("Activity of Comets under Partial Gravity") project. This especially concerns gravity levels between 10-2 and 10-4g, where the duration of the adjusted acceleration ranges from 2.5 to 3.2 s. In order to simulate the conditions of SSSB as accurately as possible, an acceleration system based on servo motors and spindle axes has been developed. The accelerations are transferred from the motors to the spindle axes containing a comet-like sample. The current dimensions of the total load (including sample, sample holder, data- and communication box) are 315 × 160 × 331 mm3 (w × d × h), with a total weight of ∼15 kg. These are together placed inside a vacuum chamber providing a vacuum quality of 10-6 mbar. The whole setup is installed inside the Einstein-Elevator. Our results show that, with the current setup, we are able to generate conditions from 10-2g down to 10-3g. The maximum deviations under these conditions are ±5 · 10-4g. At 10-2g, the duration of the experiment is at least 2.5 s limited by the travel distance of the used spindle axes, whereas at 10-4g, a minimum duration of 3.5 s is planned. Moreover, the experiments can be conducted under vacuum conditions of 10-6 mbar. The results in this paper serve as a proof of concept for the generation and control of adjustable gravity levels for future SSSB experiments.

Studying asteroids addresses a number of unknowns in planetary science. Investigating them makes use of asteroidal meteorites, remote observations and space-based missions. However, to fully investigate these objects, analysis of pristine asteroid material in Earth-based laboratories is necessary. This requires missions which travel to an asteroid and return samples to Earth. The Hayabusa, Hayabusa2 and OSIRIS-REx sample return missions have showcased the criticality of having asteroid material in hand. Returned samples exhibit fragile mineralogy which does not survive meteorite fall, and is too small to be identified via remote sensing. These missions paved the way for the deployment of future missions including sample return from the Martian moon Phobos, and visiting Psyche - the remanent core of a differentiated body. The study of asteroids, and particularly asteroid sample return, is necessary for the next generation of discoveries. Analysis of pristine asteroid material in Earth-based laboratories is critical to address many outstanding questions in planetary science. Asteroid sample return missions are therefore crucial for the next generation of discoveries.

The Middle-Wave Infrared Imaging Spectrometer for Target Asteroids (MIST-A) will be launched in 2028 aboard the Emirates Mission to the Asteroid belt (EMA) and will operate in the 2-5 μm spectral range to study the asteroids' surface composition and thermo-physical properties. MIST-A's Optical Head (OH) design is inherited from the Jovian IR Auroral Mapper (JIRAM), from which the instrument also received two spare Hybrid-Thinned Mercury-Cadmium-Telluride (MCT) photodetectors: the Engineering Model EM2 and the Flight Spare FS1. These are tested to assess their performance after a long period of storage. The laboratory setup for testing both detectors consists of a blackbody and a cryostat which houses the focal plane, maintained at temperatures of 85 K, its nominal operative temperature, and 90 K. Two sets of measurements are performed: (1) characterization of the dark current at different integration times (0 ms, 224 ms, 448 ms, 672 ms, 869 ms, 1120 ms); (2) verification of the detectors' response linearity, measuring a blackbody at different temperatures (from 50 °C to 100 °C), including ambient temperature (25 °C, with the blackbody turned off). The results of these tests confirm that both models are fully operational and allow us to evaluate the consequences of the years of inactivity on their performance. Through a detailed analysis of the detectors' properties and a comparison study with the results of the sensors' first characterization performed by their producer in 2009, we come to the conclusion that both instruments are able to fulfill MIST-A's scientific requirements. The FS1 displays a better performance with respect to the EM2 and for this has been selected as MIST-A's Flight Model.

China's deep space exploration missions have returned or will return samples from the Moon (Chang'e 5/6), asteroids (Tianwen II), and Mars (Tianwen III). The detailed mineral distribution characteristics of these samples are critical for understanding the genesis, environmental characteristics, and evolutionary history of these celestial bodies. In order to analyze the mineral type, distribution, and morphology at the microscale, we designed and developed a microscopic component coupled with a widely used visible near-infrared spectrometer (Micro-VNIR system). This system is capable of acquiring VNIR spectra from a micro-region with a spot size of approximately 700 μm in diameter and micro-images covering 3 mm × 3 mm at a spatial resolution of ∼2.08 μm. The Micro-VNIR system is applied to the mineralogical analysis of lunar meteorites NWA 8127 and NWA 8687, successfully capturing mineral components (olivine, low-Ca pyroxene, and high-Ca pyroxene) that offer direct evidence for the crystallization differentiation and magmatic evolution. The impact melting signatures (spectrally suppressed zones) confirm that both meteorites experienced complex multi-stage histories involving mantle crystallization, magmatism, and impacts. This work demonstrates that the developed Micro-VNIR system enables synergistic acquisition of VNIR spectra and micro-images from extraterrestrial materials, and provides a reliable technical support for future detailed mineralogical studies of returned samples from the Moon, asteroids, and Mars.

Thermal inertia is used to infer physical properties of asteroid surfaces. The carbonaceous asteroid Bennu has low thermal inertia suggestive of a surface covered in sub-centimeter rock fragments. However, spacecraft observations revealed that Bennu is instead blanketed by boulders of differing physical properties, with the most abundant population displaying very low thermal inertia compared to carbonaceous chondritic meteorites. Here we show that morphologically distinct particles in samples returned from Bennu also possess distinct thermal and physical properties, consistent with their genetic connection to the boulders. Angular particles have higher thermal inertia, greater hardness, and fewer but longer cracks that lead to more efficient splitting, relative to the hummocky particles. A hummocky particle exhibits low thermal inertia at sub-millimeter scales due to fine pores. Tortuous crack networks in hummocky particles further reduce thermal inertia while resisting disaggregation. Samples from Ryugu, a carbonaceous asteroid with similarly low thermal inertia, have cracks like those in Bennu's hummocky particles yet have bulk densities that indicate lower porosity. These observations imply that the low thermal inertia of both asteroids is driven by cracks in rocks resulting from geological processes within the parent body or, more recently, micrometeoroid impacts and thermal fatigue.

In 2026, we are sending probes to Mars, mining metals from asteroids, and debating whether artificial intelligence should write our operative notes, yet we are still arguing about which tendon to use for anterior cruciate ligament reconstruction. Amid the noise, the quadriceps tendon has quietly re-emerged as the pragmatic choice in a field long dominated by graft dogma. With its broad cross-sectional area, favorable collagen alignment, and lower donor-site morbidity, it offers an appealing balance between biomechanics and biology. Recent evidence shows comparable stability and superior patient comfort compared with bone-patellar tendon-bone and hamstring grafts, particularly in athletes and revision cases. The quadriceps graft combines strength, predictability, and humility-it performs without demanding worship. As we move toward precision surgery and personalized orthopedics, perhaps the real question is no longer which graft is superior, but whether our reasoning has evolved as fast as our technology.

The advancement of space exploration into an era of sample return missions from Mars, asteroids, and icy moons raises the potential for biological contamination either to or from Earth. We consider the possibility that extraterrestrial organisms introduced to Earth could behave analogously to invasive species by destabilizing ecosystems or interacting unpredictably with their new environment. There are myriad cases of microbial organisms rapidly adapting to novel extreme conditions, undermining the notion that extraterrestrial life (e.g., indigenous to Mars) would be unable to survive on Earth. The plausibility of encountering extraterrestrial life warrants stringent planetary protection measures grounded in biosafety and biosecurity principles. Due to its proximity, natural isolation, and apparent lack of a biosphere, the Moon can serve as a secure site for biocontainment of extraterrestrial samples. Building upon historical lessons from biological invasions, we argue that a lunar quarantine infrastructure should form the cornerstone of modern astrobiological risk mitigation strategies.

This review of martian organic geochemistry aims to contextualize recent findings of organic molecules in martian meteorites and from Mars missions within the broader study of origins of life on Earth. Analyzing martian organic inventories helps us understand the abiotic processes in planetary environments that are common wherever rocks interact with liquid brines and that likely contributed to the emergence of life on Earth. Mars is only the second planetary body studied for organic molecules; while carbonaceous meteorites, comet missions, and sample-return analyses of comets and asteroids have shown the diversity of organics across the solar system, studying Mars reveals what these molecules are on another planet. Although a definitive sign of extraterrestrial life has not yet been found, the findings provide insights into abiotic synthesis mechanisms that would have occurred on early Earth. At worst, these observations represent the oldest planetary record of organic and prebiotic chemical synthesis pathways that could have led to life, as inferred from the alteration of Earth's oldest rocks. They may also point to potential habitats for past martian life. Currently, samples collected by the Perseverance rover represent a unique opportunity to verify which of the two questions, "Are we alone?" or "How did we get here?" will be true for Mars. Without doubt, these questions would be best addressed through the use of higher resolution analyses by more advanced and sensitive instrumentation after sample return to Earth. Even if no definitive signs of life are found in returned samples, they would give us the opportunity to study the missing link to life on Earth, that of the primordial abiotic organic chemical processes that could have led to life. Therefore, there are no wrong answers to exploring Mars for signs of life; its secrets will illuminate our understanding of ourselves and our place in the universe, whatever the answer.

Understanding the nature of nitrogen reservoirs in primitive small bodies is fundamental for tracing the evolution of volatiles in the early Solar System and their contribution to prebiotic chemistry. Here we report the identification, via infrared spectroscopy, of ammonium (NH4+)-bearing phyllosilicates inclusions in samples returned from carbonaceous asteroids Ryugu and Bennu. Typically hundreds of micrometers in size, they exhibit highly similar near-infrared spectral profiles in both collections, pointing to a generic formation process across this class of primitive objects. This process implies a chemical path that likely starts with highly soluble ammonium salts trapped in ices and mixed with anhydrous silicates, as detected on comet 67 P/Churyumov-Gerasimenko, and ends with ammoniated phyllosilicates, and a few less soluble ammonium salts such as the Hydrated Ammonium Magnesium Phosphorus-rich grains found in Ryugu and Bennu. These second-generation ammonium-bearing species were thus able to contribute efficiently to the delivery of nitrogen to terrestrial planets.

Phosphorus (P) is a critical element for life, yet its primary geochemical form-orthophosphate-is poorly soluble and unreactive under early Earth conditions, presenting the longstanding "phosphate problem" in prebiotic chemistry. In this brief review, we give an overview of various prebiotic P sources from geochemical viewpoint. We then also discuss the feasibility of reactive P-N species in aqueous ammoniacal solutions on the early Earth. This review article also suggests the formation of inorganic P-N species in aqueous solutions. Reduced phosphorus compounds, such as phosphite produced by schreibersite corrosion and other terrestrial processes, as well as condensed phosphates and phosphites like trimetaphosphate and pyrophosphite, can react with aqueous ammonia under anoxic (or even oxic) conditions to yield amidophosphates and amidophosphites. These P-N species are more soluble, highly reactive toward organic substrates, and capable of driving phosphorylation under mild environmental conditions. Serving early Earth as an example, we further explore the potential for similar chemistry beyond Earth, particularly in ammonia-bearing aqueous environments on Mars, Enceladus, and other ocean worlds where reduced phosphorus and hydrothermal systems may coexist. We also briefly discuss the recent findings of various P species in asteroids Ryugu and Bennu. We further suggest that P-N chemistry could represent a widely accessible route to organophosphorus compounds, with important implications for the emergence of life in diverse habitable settings.

Symbiotic relationships are ubiquitous across nature and play key roles in the maintenance of biodiversity and ecosystem function. The Myzostomida are an enigmatic clade of marine annelids that live as obligate symbionts on or inside their predominantly echinoderm hosts. Species of myzostomid have diverse morphologies and lifestyles, ranging from cyst and gall forming, to parasitic host eating, and free-living ectocommensalism. Largely described from shallow tropical waters, there is currently limited information on myzostomids from the deep sea. Here we describe, using integrated morphological and molecular data, the first genus and two species of myzostomid from the abyssal seafloor, found living ectocommensally on porcellanasterid starfish from 3490 to 4362 m deep in the central and North Pacific Ocean. Molecular phylogenetic analyses using both nuclear (18S rRNA, H3) and mitochondrial (COI, 16S rRNA) markers recovered Myrmekimyzostomumgen. nov. as monophyletic, and the sole commensal genus in a clade of parasitic species associated with asteroids and ophiuroids. Trait-mapping across the phylogeny suggests the ancestral myzostomid form likely lived ectocommensally on stalked crinoids, with parasitism emerging multiple times in their evolutionary history. These new taxa underline the substantial ecological and evolutionary novelty that can be found in the deep sea. Zoobank: urn:lsid:zoobank.org:pub:332B8B95-F390-4D9F-B1FE-E9E4D433E24C.

The most commonly accepted scenario of early Earth includes: creation of the universe around 13.8 Ga (Giga-annus; or 109 years ago); establishment of our solar system ~ 4.60 Ga; and formation of Earth ~ 4.54 Ga. The earliest life forms on our planet so far observed to have existed, are microbes that left signals of their presence in rocks ~ 3.6 Ga - suggesting that Life forms existed within the first 940 million years after Earth's formation. However, an intriguing recent publication [1] infers that the last universal common ancestor (LUCA) likely existed by 4.2 Ga, and that the inferred LUCA had a genome of at least 2.5 Mb of DNA, encoding around 2,600 proteins; this suggests that sophisticated Life might have existed within the first 340 million years after Earth was formed. The commonly accepted geological history of early Earth suggests that the turbulent Hadean Eon lasted until 4.0 Ga, with the Late Heavy Bombardment (LHB) period occurring around 4.1 to 3.8 Ga. If Earth during the Hadean exhibited a molten surface, intense volcanic activity, and constant bombardment by asteroids and comets - how were sensitive molecules (e.g., nucleic acids, proteins) able to survive? Considering the "Lipid First" hypothesis [2], we propose that replicating lipid micelles are feasible candidates for having populated much of Earth's deep hydrothermal vents and turbulent surface within the first 340 million years of Earth's existence. These lipid micelles could therefore have provided a plausible form of "protective capsules" inside which early Life's sensitive molecules were able to evolve.

The field of marine ecotoxicology is based on a limited range of model organisms that incompletely represent sea and ocean biodiversity and ecological function. Although echinoderms have been recognised as valuable test organisms, ecotoxicological research predominantly focuses on sea urchins, with comparatively limited attention given to other classes. This review synthesises ecotoxicological studies published over the past two decades on sea stars (Asteroidea) and brittle stars (Ophiuroidea) taking into consideration contaminants investigated, the biological endpoints applied and their suitability as model organisms. An analysis of 74 studies reveals a bias towards trace elements and bioaccumulation analysis, while organic pollutants, emerging contaminants and mixture toxicity remain underrepresented. Immune and cellular biomarkers are frequently employed, whereas behavioural, developmental, reproductive and other functional endpoints are used less often. Heatmap analyses highlight disparities in contaminant/endpoint combinations and taxonomic coverage, with brittle stars particularly underrepresented in studies. It is important to note that some of the endpoints reported for asteroid and ophiuroid are compatible with non-lethal or minimally invasive methodologies. On this basis, behavioural assays are identified as a promising welfare-oriented approach for repeated measures toxicity testing. Overall, the integration of asteroids and ophiuroids into ecotoxicological bioassay batteries could enhance ecological relevance, phylogenetic breadth and ethical alignment in marine pollution assessment.

The Moon has preserved a unique record of organic matter delivered and reworked by asteroid and comet impacts. Here, we report diverse organic phases (particle-like, adhering-like, and inclusion-like) on the surfaces of lunar regolith grains returned by the Chang'e-5 and Chang'e-6 missions. They are predominantly amorphous carbon-like, containing N- and O-bearing functionalities and amide (─CONH─) linkages. The lunar organics show δD, δ13C, and δ15N values more negative than those of insoluble organic matter reported in carbonaceous chondrites and asteroids, consistent with impact-induced evaporation-condensation and surface reworking. The presence of solar wind implantation signatures in the organics supports long-term exposure on the lunar surface. Together, these findings suggest that the impacts both delivered and chemically processed organic matter on the lunar surface, generating N- and O-bearing functionalities.

In September 2022, NASA's Double Asteroid Redirection Test (DART) spacecraft crashed into Dimorphos and demonstrated the kinetic impact method of protecting Earth from asteroids. A fraction of the impulse delivered to Dimorphos was also imparted onto the Didymos system's barycenter, changing its heliocentric orbit. Here, we present the first-ever measurement of human-caused change in the heliocentric orbit of a celestial body. Thanks to stellar occultation and radar measurements, we estimate that the Didymos system experienced an along-track velocity change of -11.7 ± 1.3 micrometers per second. We constrain the heliocentric momentum enhancement factor for DART at 2.0 ± 0.3 and the bulk densities of Didymos and Dimorphos at 2600 ± 140 and 1540 ± 220 kilograms per cubic meter, respectively. Our results demonstrate that targeting the secondary asteroid in binary systems constitutes a possible strategy for kinetic impact deflection, adding to humanity's planetary defense capabilities.

Starfish play essential ecological roles as predators and ecosystem regulators; however, detailed developmental descriptions exist for only a handful of species, none of which are from the Mediterranean Sea. In this study, we provide the first full account of the development of the Mediterranean starfish Hacelia attenuata, from oocyte maturation through embryogenesis and larval formation, showing that its development largely follows the canonical pattern known from other asteroids. Oocytes resume meiosis when exposed to 1-methyladenine, exhibiting conserved features such as the formation of a nuclear actin shell for chromosome gathering prior to meiotic spindle assembly. Embryogenesis then proceeds through radial cleavages to form a ciliated blastula, followed by gastrulation via invagination and mesenchymal cell delamination. The larvae develop through typical bipinnaria and brachiolaria stages, displaying characteristic feeding structures and attachment organs. Importantly, developmental rate decreases substantially at lower temperatures, consistent with the species distribution in warm Mediterranean waters. Taken together, these findings position H. attenuata as a promising new model for studying thermal adaptation, environmental resilience, and conserved developmental mechanisms in starfish.