Future Deep Space Exploration Missions Research Articles

On-demand fabrication of piezoelectric sensors for in-space structural health monitoring

Inflatable structures, promising for future deep space exploration missions, are vulnerable to damage from micrometeoroid and orbital debris impacts. Polyvinylidene fluoride-trifluoroethylene (PVDF-trFE) is a flexible, biocompatible, and chemical-resistant material capable of detecting impact forces due to its piezoelectric properties. This study used a state-of-the-art material extrusion system that has been validated for in-space manufacturing, to facilitate fast-prototyping of consistent and uniform PVDF-trFE films. By systematically investigating ink synthesis, printer settings, and post-processing conditions, this research established a comprehensive understanding of the process-structure-property relationship of printed PVDF-trFE. Consequently, this study consistently achieved the printing of PVDF-trFE films with a thickness of around 40 µm, accompanied by an impressive piezoelectric coefficient of up to 25 pC N−1. Additionally, an all-printed dynamic force sensor, featuring a sensitivity of 1.18 V N−1, was produced by mix printing commercial electrically-conductive silver inks with the customized PVDF-trFE inks. This pioneering on-demand fabrication technique for PVDF-trFE films empowers future astronauts to design and manufacture piezoelectric sensors while in space, thereby significantly enhancing the affordability and sustainability of deep space exploration missions.

Simulation Research on the Effect of Spreading Process Parameters on the Quality of Lunar Regolith Powder Bed in Additive Manufacturing

Lunar surface additive manufacturing with lunar regolith is a key step in in-situ resource utilization. The powder spreading process is the key process, which has a major impact on the quality of the powder bed and the precision of molded parts. In this study, the discrete element method (DEM) was adopted to simulate the powder spreading process with a roller. The three powder bed quality indicators, including the molding layer offset, voidage fraction, and surface roughness, were established. Besides, the influence of the three process parameters, which are roller’s translational speed, rotational speed, and powder spreading layer thickness on the powder bed quality indicators was also analyzed. The results show that with the reduction of the powder spreading layer thickness and the increase of the rotational speed, the offset increased significantly; when the translational speed increased, the offset first increased and then decreased, which resulted in an extreme value; with the increase of the layer thickness and the decrease of the translational speed, the values for voidage fraction and surface roughness significantly reduced. The powder bed quality indicators were adopted as the optimization objective, and the multi-objective parameter optimization was carried out. The predicted optimal powder spreading parameters and powder bed quality indicators were then obtained. Moreover, the optimal values were then verified. This study can provide informative guidance for in-situ manufacturing at the moon in future deep space exploration missions.

Decoding Mission Design Problem for NTP Systems for Outer Planet Robotic Missions

This paper discusses the current challenges of exploration of outer planets and proposes a nuclear thermal propulsion (NTP) system for future deep space exploration missions. The mission design problem with respect to the NTP system is presented where it is proposed that NTP-powered missions need to integrate the requirements and constraints of mission objective, spacecraft design, NTP system design, and launch vehicle limits into a self-consistent model. The paper presents a conceptual NTP-powered rendezvous mission to Neptune that uses a single high-performance–class commercial launch vehicle to deliver over 2 mT of useful payload in a direct transfer trajectory with total trip time being under 16 years.

B-Cell Homeostasis Is Maintained During Two Months of Head-Down Tilt Bed Rest With or Without Antioxidant Supplementation.

Alterations of the immune system could seriously impair the ability to combat infections during future long-duration space missions. However, little is known about the effects of spaceflight on the B-cell compartment. Given the limited access to astronaut samples, we addressed this question using blood samples collected from 20 healthy male volunteers subjected to long-duration bed rest, an Earth-based analog of spaceflight. Hematopoietic progenitors, white blood cells, total lymphocytes and B-cells, four B-cell subsets, immunoglobulin isotypes, six cytokines involved in inflammation, cortisone and cortisol were quantified at five time points. Tibia microarchitecture was also studied. Moreover, we investigated the efficiency of antioxidant supplementation with a cocktail including polyphenols, omega 3, vitamin E and selenium. Our results show that circulating hematopoietic progenitors, white blood cells, total lymphocytes and B-cells, and B-cell subsets were not affected by bed rest. Cytokine quantification suggested a lower systemic inflammatory status, supported by an increase in serum cortisone, during bed rest. These data confirm the in vivo hormonal dysregulation of immunity observed in astronauts and show that bed rest does not alter B-cell homeostasis. This lack of an impact of long-term bed rest on B-cell homeostasis can, at least partially, be explained by limited bone remodeling. None of the evaluated parameters were affected by the administration of the antioxidant supplement. The non-effectiveness of the supplement may be because the diet provided to the non-supplemented and supplemented volunteers already contained sufficient antioxidants. Given the limitations of this model, further studies will be required to determine whether B-cell homeostasis is affected, especially during future deep-space exploration missions that will be of unprecedented durations.

Chinese Deep Space Stations: A brief review [Antenna Applications Corner

To meet the rapidly growing needs of current and future deep space exploration missions, China has developed three deep space stations: Jiamusi and Kashi, (China), and Argentina (South America), for providing continuous telemetry, tracking, and command (TT&C), reliable communication, and precise navigation services. Integrated with state-of-the-art technologies, these three deep space stations are not only powerful for transmission but also extremely sensitive for receiving. Many remarkable innovations and achievements were made during the construction process, including the beam waveguide (BWG), adjustable subreflector, high-power transmitter, cryogenic low-noise amplifier (LNA), antenna-arraying technique, digital baseband receiver, and interferometry. This article briefly reviews the system architecture, general performance, critical system design issues, and contributions made by these Chinese deep space stations (CDSSs) during Chang’e missions.

Effect of Automating Procedural Work on Situation Awareness and Workload.

In future deep space exploration missions, crew will have to work more autonomously from Earth. Greater crew autonomy will increase dependence on automated systems. This study investigates the performance effects of different strategies to automate procedural work for space exploration operations. The following strategies are investigated for performing procedural work:• Manual Work uses no procedure automation and crew performs all actions.• Shared Work uses procedure automation to perform some actions within a procedure while crew performs other actions.• Supervised Work uses procedure automation to perform procedure actions while crew supervises the automation. Twenty-seven participants participated in a planetary habitat scenario-based simulation using electronic procedures with automatable actions to investigate the effect of these strategies on situation awareness (SA) and workload. This study used a modification of the Situation Presence Assessment Method to measure SA and the Bedford Workload Scale to measure subjective workload. Mean response times and accuracy for SA queries show no significant difference among the three strategies. Bedford Workload ratings compared across the three strategies indicate that participants rated their workload as highest in the Manual Work condition, followed by the Shared Work condition, and lowest in the Supervised Work condition. The study hypothesized that increased levels of automation would lead to lower subjective workload and decreased SA. Although no significant difference in SA was observed, subjective workload was lower in automation strategies. Based on subjective ratings, 93% of participants preferred some form of automation, with 56% preferring the Shared Work automation condition.

Extraction and analysis of planetary volatiles

<p indent="0mm">Planetary volatiles refer to material components that can be separated from a solid sample as a gas phase via physical processes such as impact and heating. On the one hand, these materials are crucial for studying the formation of the solar system and the evolution of planets and their satellites. On the other hand, they provide resources for deep space exploration. Along with the exploration of deep space in recent decades, the detection of volatiles has also advanced our understanding of the cosmos. For example, the discovery of the Moon’s polar ice has changed the impression that the Moon seriously lacks volatiles, the discovery of suspected biogenic methane on Mars has rekindled people’s hope that Mars may once have harbored life, and studies of the hydrogen isotopes in comet 67P have suggested that most of the water on Earth had come from asteroids instead of comets. The combination of pyrolysis in a high-temperature furnace with mass spectrometry is the main method used to extract and analyze volatiles from deep space. This paper summarizes the extraction methods used and the functional parameters of volatile extraction payloads in deep space exploration and compares the performance indexes of the mass spectrometers used for volatile analysis. Furthermore, this paper introduces some volatiles payloads that may be extracted and analyzed in future deep space exploration missions.

Location and Accuracy Validation of Lunar Landing Point Based on Multi-source Images

High-precision positioning of the landing site is a critical step in the mission and an important prerequisite for surface operations of the lander and rover. In this paper, a high-precision positioning method of the landing site was designed based on image feature matching and multiple image localization methods. And the positioning experiment and accuracy validation were carried out in ChangE-3 landing site. On the basis of high-precision image matching and geometric transformation, the matching precision between the sequent descent images reached sub-pixel, and the matching accuracy between LRO NAC image and medium-resolution descent image was better than 1 pixel. The landing position was calculated to be (44.1196^°N, 19.5148^°W). This method comprehensively utilized multi-source images, and didnt entirely depend on the mapping accuracy of the landing base map. It was a further refinement of the matching results between the images and landing base map. So, this high-precision positioning method can be applied in future deep space exploration missions.

Analysis of fusion propulsion system for Earth-to-Mars mission

The high-performance space propulsion system is required for deep space exploration, such as Mars and Jupiter missions. The fusion propulsion system has an extraordinary performance of ultra-high specific impulse, high specific power, and moderate thrust, which can reflect its advantages in future deep space exploration missions. In this study, analysis has been conducted to investigate the technical requirements of the fusion propulsion system for the Earth-to-Mars mission. An analytical model based on Williams’s assumption was adopted and solved by using the MATLAB code. Critical parameters such as specific impulse, specific power, mission time, and payload ratio for Mars rendezvous missions were analyzed. The qualitative and quantitative analysis results show that in order to reach Mars within one month with a payload ratio higher than 10 %, the specific power ranging from 5 to 15 kW/kg and the specific impulse of 10000 s is required. These parameters will take entirely inherent advantage of the fusion propulsion system. Moreover, the fusion propulsion system can operate under the optimal condition, including a wide range of the specific power (1−100 kW/kg) and the specific impulse (10000–200000 s). Based on a comprehensive analysis of the space mission performance, it is possible to provide a significant reference for the development of the fusion space propulsion system.

Impact of galactic cosmic ray simulation on nutritional content of foods

Foods packaged for future deep-space exploration missions may be prepositioned ahead of astronaut arrival and will be exposed to galactic cosmic rays (GCRs) and solar radiation in deep space at higher levels and different spectrums than those found in low-Earth orbit (LEO). In this study, we have evaluated the impact of a GCR simulation (approximately 0.5 and 5 Gy doses) at the NASA Space Radiation Laboratory (NSRL) on two retort thermostabilized food products that are good sources of radiation labile nutrients (thiamin, vitamin E, or unsaturated fats). No trends or nutritional differences were found between the radiation-treated samples and the control immediately after treatment or one-year after treatment. Small changes in a few nutrients were measured following one-year of storage. Further studies may be needed to confirm these results, as the foods in this study were heterogeneous, and this may have masked meaningful changes due to pouch-to-pouch variations.

Plasticity of the human IgM repertoire in response to long-term spaceflight.

Immune dysregulation is among the main adverse outcomes of spaceflight. Despite the crucial role of the antibody repertoire in host protection, the effects of spaceflight on the human antibody repertoire are unknown. Consequently, using high-throughput sequencing, we examined the IgM repertoire of five cosmonauts 25days before launch, after 64±11 and 129±20days spent on the International Space Station (ISS), and at 1, 7, and 30days after landing. This is the first study of this kind in humans. Our data revealed that the IgM repertoire of the cosmonauts was different from that of control subjects (n=4) prior to launch and that two out the five analyzed cosmonauts presented significant changes in their IgM repertoire during the mission. These modifications persisted up to 30days after landing, likely affected the specificities of IgM binding sites, correlated with changes in the V(D)J recombination process responsible for creating antibody genes, and coincided with a higher stress response. These data confirm that the immune system of approximately half of the astronauts who spent 6months on the ISS is sensitive to spaceflight conditions, and reveal individual responses indicating that personalized approaches should be implemented during future deep-space exploration missions that will be of unprecedented durations.

中国深空测控网光通信技术途径分析与发展展望（特约）

Deep space optical communication is the main technical approach of high speed data transmission to meet the future deep space exploration, and the main technical direction for the China Deep Space TT&C Network development. Especially with the development of intelligent and networked space communication system, the intelligent space communication network combining RF and optical communication will become the core facilities to support future deep space exploration missions. This paper combines China future lunar and deep space exploration development plan, based on the mission support capability of China Deep Space TT&C Network, the requirements of future deep space optical communication are sorted out. On the basis of learning from the latest research results, this paper analyzes the technical approach of constructing the earth terminal of deep space optical communication system. Based on the actual situation of China, this paper puts forward the development idea of constructing the mixed deep space optical communication ground system with space relay terminal and earth terminal, and finally forming the cognitive network of deep space optical communication.

Medical Event Management for Future Deep Space Exploration Missions to Mars

BackgroundLong-duration exploration missions (LDEMs), such as voyages to Mars, will present unique medical challenges for astronaut crews, including communication delays and the inability to return to Earth early. Medical events threaten crewmember lives and increase the risk of mission failure. Managing a range of potential medical events will require excellent technical and nontechnical skills (NTSs). We sought to identify medical events with potential for rescue, range them according to the potential impact on crew health and mission success during LDEMs, and develop a list of NTSs to train for management of in-flight medical events. Materials and methodsTwenty-eight subject matter experts with specializations in surgery, medicine, trauma, spaceflight operations, NTS training, simulation, human factors, and organizational psychology completed online surveys followed by a 2-d in-person workshop. They identified and rated medical events for survivability, mission impact, and impact of crewmember NTSs on outcomes in space. ResultsSudden cardiac arrest, smoke inhalation, toxic exposure, seizure, and penetrating eye injury emerged as events with the highest potential mission impact, greatest potential for survival, and that required excellent NTS for successful management. Key NTS identified to target in training included information exchange, supporting behavior, communication delivery, and team leadership/followership. ConclusionsWith a planned Mars mission on the horizon, training countermeasures need to be developed in the next 3-5 y. These results may inform policy, selection, medical system design, and training scenarios for astronauts to manage in-flight medical events on LDEMs. Findings may extend to surgical and medical care in any rural and remote location.

Zoster patients on earth and astronauts in space share similar immunologic profiles

BackgroundOn long-duration spaceflight, most astronauts experience persistent immune dysregulation and the reactivation of latent herpesviruses, including varicella zoster virus (VZV). To understand the clinical risk of these perturbations to astronauts, we paralleled the immunology and virology work-up of astronauts to otherwise healthy terrestrial persons with acute herpes zoster. MethodsBlood samples from 42 zoster patients – confirmed positive by PCR for VZV DNA in saliva (range from 100 to >285 million copies/mL) were analyzed for peripheral leukocyte distribution, T cell function, and plasma cytokine profiles via multi-parametric flow cytometry and multiplex bead-based immune-array assays. Patient findings were compared to normal value ranges specific for each assay that were defined in-house previously from healthy adult test subjects. ResultsCompared to the healthy adult ranges, the zoster patients possess (1) a higher proportion of constitutively activated T-cells, (2) a T-cell population skewed towards a more experienced maturation state, (3) depressed general T-cell function, and (4) a higher concentration of 20 of 22 measured plasma cytokines. DiscussionThe pattern of immune dysregulation in zoster patients is similar to that of astronauts during spaceflight who shed VZV DNA in their saliva. Because future deep space exploration missions will be of an unprecedented duration, prolonged immune depression and chronic viral reactivation threaten to manifest overt disease in exploration class astronauts.

Performance improvement of the μ10 microwave discharge ion thruster by expansion of the plasma production volume

To improve the performance of the 10-cm-class microwave discharge ion thruster μ10 for use in future deep space exploration missions planned by the Japan Aerospace Exploration Agency (JAXA), a new discharge chamber was designed, and its performance was tested. The maximum beam current in the new discharge chamber geometry was 16% higher than that in the original geometry, which was used in the Hayabusa 2 space explorer, under the same discharge power. To investigate the reason for this performance improvement, the multi-charged ion ratio in the plume, the beam current density profiles, and the ion current in the discharge chamber were measured by probes. It was found that the multi-charged ion efficiency and the beam divergence efficiency in the redesigned configuration were not significantly different from those in the Hayabusa 2 configuration. This shows that the increase in the ion beam current enhances the thrust. In addition, it was confirmed that the total ion current inside the new discharge chamber is higher than that in the Hayabusa 2 configuration. The ion extraction efficiency, however, was lower than that in the Hayabusa 2 configuration. This suggests that the increase in the total ion current per unit of incident microwave power is the cause of the performance improvement. In the redesigned configuration, the thrust is 12.0 mN, the specific impulse is 3122 s, the discharge loss is 162 W/A, and the propulsion efficiency is 39.6% at the peak performance point.

The process and experience in the development of Chinese lunar probe

After introducing the implementation strategy and the orbiting, soft lander and sample return phases of Chinese lunar exploration program, the paper focuses on the lunar probes or satellites of Chinese lunar exploration program, and systematically presents the mission requirements and characterization, the designing outlines and key implementation approach of the ChangE-1, ChangE-2, ChangE-3 and ChangE-5 missions. The paper also analyzes the technical leapfrogging and achievements of the successfully realized orbiter and lander/rovers missions. The experience summarized in this paper has great application value in the mission planning and implementation of the future deep space exploration missions.

Crew autonomy for deep space exploration: Lessons from the Antarctic Search for Meteorites

Future piloted missions to explore asteroids, Mars, and other targets beyond the Moon will experience strict limitations on communication between vehicles in space and control centers on Earth. These limitations will require crews to operate with greater autonomy than any past space mission has demonstrated. The Antarctic Search for Meteorites (ANSMET) project, which regularly sends small teams of researchers to remote parts of the southern continent, resembles a space mission in many ways but does not rely upon a control center. It provides a useful crew autonomy model for planners of future deep space exploration missions. In contrast to current space missions, ANSMET gives the crew the authority to adjust competing work priorities, task assignments, and daily schedules; allows the crew to be the primary monitor of mission progress; demands greater crew accountability for operational errors; requires the crew to make the most of limited communication bandwidth; adopts systems designed for simple operation and failure recovery; and grants the crew a leading role in the selection and stowage of their equipment.

Analysis of telescope array receivers for deep-space inter-planetary optical communication link between Earth and Mars

Optical communication technology shows promising prospects to fulfill the large bandwidth communication requirements of future deep-space exploration missions that are launched by NASA and various other international space agencies. At Earth, a telescope with a large aperture diameter is required to capture very weak optical signals that are transmitted from distant planets and to support large bandwidth communication link. A single large telescope has the limitations of cost, single point failure in case of malfunction, difficulty in manufacturing high quality optics, maintenance, and trouble in providing communication operations when transmitting spacecraft is close to the Sun. An array of relatively smaller-sized telescopes electrically connected to form an aggregate aperture area equivalent to a single large telescope is a viable alternative to a monolithic gigantic aperture. In this paper, we present the design concept and analysis of telescope array receivers for an optical communication link between Earth and Mars. Pulse-position modulation (PPM) is used at the transmitter end and photon-counting detectors along with the direct-detection technique are employed at each telescope element in the array. We also present the optimization of various system parameters, such as detector size (i.e., receiver field of view), PPM slot width, and the PPM order M, to mitigate the atmospheric turbulence and background noise effects, and to maximize the communication system performance. The performance of different array architectures is evaluated through analytical techniques and Monte-Carlo simulations for a broad range of operational scenarios, such as, Earth–Mars conjunction, Earth–Mars opposition, and different background and turbulence conditions. It is shown that the performance of the telescope array-based receiver is equivalent to a single large telescope; and as compared to current RF technology, telescope array-based optical receivers can provide several orders of magnitude greater data rates for deep-space communication with Mars.

Development of Oscillation-Free Attitude Maneuvering System for Spinning Solar Sail

Solar sail is one of the promising propulsion systems for future deep space exploration missions as it does not require any fuel to acquire propulsive force. Although folding method and deployment mechanism of the sail have been intensively developed, attitude control of the solar sail, which is necessary for the orbital control by the solar sail, has not been much studied. This paper discusses the attitude dynamics and the control method of a spinning type solar sail spacecraft. The spinning type solar sail, where the sail equipped around the spacecraft hub is to be deployed and extended by centrifugal force, has no rigid structure supporting its membrane. This type of mechanism has the advantage in its simple and lightweight structure, however, the attitude control is difficult due to the flexibility of the membrane. In this paper, we introduced a mathematical dynamics model including first oscillation mode of the membrane which can handle coupled motion of a rigid spacecraft and a flexible membrane, and analytically developed a controller that can avoid unnecessary oscillatory motion. The performance of the controller was verified by numerical simulations using more precise multi-particle numerical model.