After decades where human spaceflight missions have been reserved to low Earth orbit, recent years have seen mission proposals and even implemented plans, e.g. with the mission Artemis I, for returning to the lunar surface. SpaceX has published over various media (e.g., its official website, conference presentations, user manual) conceptual information for its reusable Starship to enable human exploration missions to the Martian surface by the end of the decade. The technological and human challenges associated with these plans are daunting. Such a mission at that distance would require excellent system reliability and in-situ-resource utilization on a grand scale, e.g. to produce propellant. The plans contain little details however and have not yet been reviewed concerning their feasibility. In this paper we show significant technological gaps in these plans. Based on estimates and extrapolated data, a mass model as needed to fulfill SpaceX's plans could not be reproduced and the subsequent trajectory optimization showed that the current plans do not yield a return flight opportunity, due to a too large system mass. Furthermore, significant gaps exist in relevant technologies, e.g. power supply for the Martian surface. It is unlikely that these gaps can be closed until the end of the decade. We recommend several remedies, e.g. stronger international participation to distribute technology development and thus improve feasibility. Overall, with the limited information published by SpaceX about its system and mission scenario and extrapolation from us to fill information gaps, we were not able to find a feasible Mars mission scenario using Starship, even when assuming optimal conditions such as 100% recovery rate of crew consumables during flight.
Historically, spacecraft have followed trajectories that took between six and nine months to reach Mars, using traditional chemical propulsion on roughly Hohmann transfers. It is commonly believed that advances in propulsion technology, such as nuclear thermal or VASIMR, are necessary to reduce that transit time. In this paper, we show the feasibility of transit to Mars using the SpaceX Starship taking 90 days. We outline two trajectories that reduce each transit to between 90 and 104 days each way. These trajectories are within NASA career radiation limits, while 180-day trajectories are not.
[This corrects the article DOI: 10.1016/j.isci.2024.111382.].
Human spaceflight has historically been managed by government agencies, such as in the NASA Twins Study1, but new commercial spaceflight opportunities have opened spaceflight to a broader population. In 2021, the SpaceX Inspiration4 mission launched the first all-civilian crew to low Earth orbit, which included the youngest American astronaut (aged 29), new in-flight experimental technologies (handheld ultrasound imaging, smartwatch wearables and immune profiling), ocular alignment measurements and new protocols for in-depth, multi-omic molecular and cellular profiling. Here we report the primary findings from the 3-day spaceflight mission, which induced a broad range of physiological and stress responses, neurovestibular changes indexed by ocular misalignment, and altered neurocognitive functioning, some of which match those of long-term spaceflight2, but almost all of which did not differ from baseline (pre-flight) after return to Earth. Overall, these preliminary civilian spaceflight data suggest that short-duration missions do not pose a significant health risk, and moreover present a rich opportunity to measure the earliest phases of adaptation to spaceflight in the human body at anatomical, cellular, physiological and cognitive levels. Finally, these methods and results lay the foundation for an open, rapidly expanding biomedical database for astronauts3, which can inform countermeasure development for both private and government-sponsored space missions.
Genomic plasticity helps adapt to extreme environmental conditions. We tested the hypothesis that exposure to space environment (ESE) impacts the epigenome inducing genomic plasticity. Murine skin samples from the Rodent Research Reference Mission-1 were procured from the International Space Station (ISS) National Laboratory. Targeted RNA sequencing to test differential gene expression between the skin of ESE versus ground controls revealed upregulation of VEGF-mediated angiogenesis pathways secondary to promoter hypomethylation in responders. Methylome sequencing identified ESE-sensitive hypomethylated genes including developmental angiogenic genes Araf, Vegfb, and Vegfr1. Based on differentially expressed genes, the angiogenesis biofunction was enriched in responders. The induction of genomic plasticity in response to ESE, as reported herein, may be viewed as a mark of biological resilience that is evident in a minority of organisms, responders but not in non-responders, exposed to the same stressor. Inducible genomic plasticity may be implicated in natural resilience to ESE.
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Geomagnetic storms of G1-class were observed on 3 and 4 February 2022, which caused the loss of 38 out of 49 SpaceX satellites during their launch due to enhanced neutral density. The effects of storm-time neutral dynamics and electrodynamics over the American sector during this minor storm have been investigated using Global Positioning System-total electron content (TEC) and Global-scale Observations of the Limb and Disk (GOLD) mission measured thermospheric composition and temperature. Results revealed an unexpected feature in terms of increase in O/N2 and depletion in TEC over the American low-latitudes. This feature is in addition to the classic storm time ionospheric variations of enhancement in ionospheric electron density in presence of enhanced O/N2 and an intense equatorial electrojet (EEJ). Further, significant morning-noon electron density reductions were observed over the southern mid-high latitudes along the American longitudes. Results from Multiscale Atmosphere-Geospace Environment (MAGE) model simulations elucidated storm-induced equatorward thermospheric wind which caused the strong morning counter electrojet by generating the disturbance dynamo electric field. This further explains the morning TEC depletion at low-latitudes despite an increase in O/N2. Sub-storm related magnetospheric convection resulted in significant noon-time peak in EEJ on 4 February. Observation and modelling approaches together suggested that combined effects of storm-time neutral dynamic and electrodynamic forcing resulted in significant ionospheric variations over the American sector during minor geomagnetic storms.
Reports of audible sonic booms along the south-central California coast during SpaceX Falcon 9 launch ascents prompted measurements in Ventura County during summer 2024. A total of 132 measurements were made over six launches, with 16-25 measurements per launch. The maximum overpressure measured was 1.90 psf (133 dB), but most measured booms had an overpressure below 0.5 psf and durations of several seconds. Two launches had appreciably lower overpressures and smaller terrestrial footprint, indicating that both meteorology and launch azimuth are important factors in terrestrial boom audibility. Agreement between this dataset and environmental assessment predictions was marginal.
So far, space exploration has attracted increasing scientific interest due to the growth of missions promoted by private investment, such as SpaceX, Boeing, Blue Origin, and the recent attention generated by astronomical phenomena such as 3I/ATLAS. However, access to space experimentation remains limited and expensive. For this reason, new approaches to simulate space conditions on Earth are being developed to broaden research opportunities bio-inspired by plant responses to phototropism and geotropism. In this context, Betta Aerospace has continued the development of a microgravity simulation system consisting of a 3-axis clinostat powered by a single motor, continuous external electrical supply, and, in this project, a continuous external liquid supply. The proposed pioneer system was designed as a flexible platform manufactured through reinforced 3D printing, with an approximate size of 30 cm, an estimated payload of 30 kg, and a 24 V supply. Its main goal is to study the effects of simulated microgravity on aquatic organisms while enabling longer observation times in a controlled freshwater environment. Candidate biological samples include Ulva lactuca, Pyropia, Spirulina/Arthrospira, and Chlorella. Preliminary motion tests confirmed continuous operation at 10 rpm. In addition, a simplified static finite element analysis under a 294 N load yielded a maximum von Mises stress of 5.45 × 107 Pa and a maximum displacement of 1.73 mm.
Extracellular vesicles (EVs) serve as critical regulators of intercellular communication by carrying diverse molecular cargos which reflect cellular states associated with environmental stressors. We investigated transcriptomic profiles of EVs derived from human skeletal muscle tissue chips flown abroad the SpaceX CRS-25 mission to characterize age- and microgravity-induced adaptation. EVs were isolated using a novel magnetic capture-release method (ExCy) from conditioned media of muscle chips cultured in microgravity or ground control conditions. Next-generation sequencing and differential gene expression analysis were performed on EV RNA. In this exploratory study, we identified age- and spaceflight-specific transcriptomic signatures. Young donor-derived EVs in microgravity appear to exhibit upregulation of oxidative stress and signaling pathways, while older donor-derived EVs showed markers of mitochondrial quality control, ER stress, and proteostasis failure. Muscle-derived EVs capture environment- and age-dependent molecular signatures in space, supporting their use as non-invasive biomarkers for physiological stress and tissue adaptation under microgravity.
Jessica Meir is a NASA astronaut, marine biologist, and physiologist. She flew for the first time to the International Space Station (ISS) in 2019 where she served as a flight engineer for Expedition 61/62. Before becoming an astronaut, her scientific career focused on the physiology of animals in extreme environments. She studied the diving physiology of emperor penguins in Antarctica and elephant seals in Northern California during her Ph.D., and she worked with high-flying bar-headed geese during her postdoctoral research. As an astronaut, she has extensive experience developing, teaching, coordinating and performing biology experiments in space or equivalent reduced-gravity settings. Dr. Meir will serve as spacecraft commander for NASA’s SpaceX Crew-12 mission, which will launch to the ISS in February 2026 for another science expedition. In this Q&A, she discusses her passion for biology and the value of conducting scientific research in space.
The adverse effects of spaceflight on skeletal health are well documented; however, the onset and underlying mechanism of these changes remain poorly understood. This study investigated alterations in bone microarchitecture, density, strength, and remodeling in eight crew members (four males, four females) aboard the SpaceX Crew Dragon spacecraft as part of the Fram2 and Polaris Dawn missions. The primary aim of this study was to investigate the impact of short-duration spaceflight (3-5 days) on bone strength and microarchitecture to determine the onset of bone deterioration. Secondary objectives included examining how these changes compared to typical age-related bone loss and potential sex-specific differences in the skeletal response to microgravity. High-resolution peripheral quantitative computed tomography (HR-pQCT) scans of the distal radius and tibia were performed pre- and post-spaceflight. Postflight, the tibia demonstrated significant reductions in total bone density (p < 0.05), and adverse alterations in trabecular bone microarchitecture, including decreased trabecular bone density (p < 0.05), trabecular thickness (p < 0.01) and separation (p < 0.05). In contrast, the radius exhibited no significant changes in bone density, microarchitecture or strength. These findings suggest there is early onset of bone loss and microstructural changes following 3-5 days in microgravity, highlighting the value of short-duration missions for studying skeletal deterioration that may be used for the future development and assessment of targeted skeletal countermeasures.
Spaceflight induces altered physiology that has the potential to alter medication pharmacokinetics due to factors including gastrointestinal motility, fluid balance, circulatory dynamics, hormonal changes, and metabolic alterations. Here, we report the first pharmacokinetic analysis using blood samples during spaceflight. The four SpaceX Polaris Dawn crewmembers ingested 500 mg of oral acetaminophen pre-flight, in-flight, and post-flight. Post-ingestion capillary blood samples were collected using volumetric absorptive microsampling (VAMS). Samples were analyzed using liquid chromatography-tandem mass spectrometry. All samples collected in microgravity were adequate for post-flight analysis. Compared to pre-flight baseline, in-flight increases were observed in the Cmax (mean [SD] ng/mL: pre-flight = 9110 [3290], in-flight = 43,300 [5700], P < .001), AUC0-last (mean [SD] h ng/mL: pre-flight = 26,100 [4520], in-flight = 109,000 [29,400]), and λz (mean [SD] 1/h: pre-flight = 0.227 [0.0688], in-flight = 0.336 [0.0209]). Compared to pre-flight baseline, in-flight decreases were observed in tmax (mean [SD] h: pre-flight = 1.06 [0.657], in-flight = 0.688 [0.239]), t1/2 (mean [SD] h: pre-flight = 3.27 [0.950], in-flight = 2.07 [0.130]), CL/F (mean [SD] mL/h: pre-flight = 16,200 [2990], in-flight = 3890 [559]), and Vz/F (mean [SD] mL: pre-flight = 74,700 [18,800], in-flight = 11,500 [1100]). Compared to pre-flight baseline, Cmax, AUC, and λz increased in-flight, while tmax, t1/2, Vz/F, and CL/F decreased in-flight. Cmax, AUC, Vz/F, and CL/F showed residual changes 3 days post-flight (R + 3). Supratherapeutic blood levels with standard terrestrial dosing raises concern for inadvertent toxicity in the spaceflight environment, and highlights the value of further pharmacokinetic study of medications commonly included within spaceflight medical systems. Overall, VAMS enabled pharmacokinetic study during spaceflight and could serve as a platform for future pharmacokinetic studies.
Spaceflight presents several unique challenges for the diagnosis and management of in-flight ocular trauma. Constrained medical resources, microgravity, and delayed access to advanced medical care require novel and unique approaches to ocular trauma. The Ocular Trauma Score (OTS), an evidence-based clinical tool, aids in establishing a prognosis for ocular injuries and offers a method of informed triage and management. As governmental space agencies and private space companies (e.g., SpaceX, Blue Origin, and Virgin Galactic) rapidly increase the number and length of human spaceflight missions, the development of increasingly autonomous medical decision-making will be critical for astronaut safety and mission success. This paper aims to evaluate the practical utility of the OTS during spaceflight and highlight potential protocols to optimize triage and management of spaceflight related ocular trauma (SROT) effectively during future missions.
This article examines how Starlink, developed by SpaceX, constitutes a disruptive innovation in the telecommunications sector in Cameroon, where it offers connectivity in areas poorly served by traditional networks. However, there is a tension between the ideal and the market realities of democratizing internet access. On one hand, like philanthrocapitalist initiatives, Starlink promotes itself through humanitarian efforts that promise global internet access, presented as a public good. On the other hand, its business strategies privatize access and make it unaffordable for a large portion of the global population. Starlink is reshaping geopolitical and economic relations not only by competing with national operators and challenging regulatory agencies, but also by cooperating with local telecom actors and, in some cases, relying on their infrastructure to ensure the continuity of its services. Its success is further supported by a widespread crisis of user mistrust in traditional telecommunications infrastructures, fueled by frequent outages and high costs, positioning Starlink as a trust infrastructure. Our analysis shows that, while Starlink claims to promote digital inclusion, its market-driven logic deepens existing inequalities-amplifying what has long been a major challenge of internet access and rendering it even more visible and politically salient in the 21st century.
Design and acquisition of large-scale complex engineered systems can use technical measures to compare system alternatives through setting constraints on those measures and/or providing objectives using the measures. Selecting a technical measure set can be uncertain, with little selection guidance available, and difficult to validate, potentially leading to omitting technical measures. This research examines the impact of omitting technical measures on system alternative selection using a case study of real-world technical measures and system alternatives. A requirements-based constraint framework and an optimization-based objective function framework are developed using a set of real-world technical measures. The research models how omissions of technical measures lead to choosing a different system alternative. The impacts are demonstrated through an application of the NASA Human Landing System (HLS) using 13 system alternatives, including the systems proposed to NASA by Blue Origin, SpaceX, and Dynetics. The research finds that omissions in the constraint framework open the design space, potentially changing the system alternative chosen. Omissions in the objective function framework alter the indicated ordinal preference for the system alternatives, changing the system alternative chosen. An omitted technical measure on the side of the acquirer may change the system alternative selected, directing millions of dollars towards a specific organization and system. This research highlights the practical impacts of omissions of technical measures for awarding contracts during system acquisition. The likelihood of omissions, the difficulty to validate outcomes, and the impacts of omissions demonstrated in this research form evidence that the connection amongst problem formulation, problem solving, and validation must be emphasized if used for system alternative selection.
Shoulder dislocations are prevalent on Earth and pose unique challenges in spaceflight and spaceflight training, particularly during extravehicular activities (EVAs). This case report describes a 50-year-old male who experienced an anterior shoulder dislocation while performing an emergency egress exercise in a SpaceX EVA suit. The report describes the medical thought process, the operational constraints, and the reduction techniques employed to achieve a successful shoulder reduction without fully removing or damaging the suit. NASA estimates a high likelihood of shoulder injuries during long-duration lunar missions, emphasizing the importance of suit designs and rescue protocols. Quick and effective medical intervention is crucial, as delays can lead to complications. This Earth-based case report provides some insight into reduction technique considerations for suited spaceflight operations in varying gravitational environments.