Spacecraft Cabin Research Articles

Robot base position and spacecraft cabin angle optimization via homogeneous stiffness domain index with nonlinear stiffness characteristics

The use of mobile robots for machining large components has received considerable research interest for the application of industrial robots in the machinery manufacturing sector. However, the low structural stiffness of industrial robots can result in poor machining quality under the action of cutting forces. Therefore, this paper proposes a simultaneous optimization method the mobile robot base position and cabin angle using homogeneous stiffness domain (HSD) index for large spacecraft cabins. First, a nonlinear joint stiffness model that considers the gravity compensator mechanism is established to describe the stiffness characteristics of heavy-duty robots more accurately. Subsequently, a HSD index is proposed to evaluate the overall stiffness values and stiffness fluctuation for all robot postures in the machining program. An optimization model is then established based on the HSD under the constraints of machining accessibility, joint angle limitation and singularity. The optimal base position and cabin angle are determined simultaneously using the sparrow search algorithm. Finally, simulation and milling experiments are used to demonstrate that the optimization method proposed in this paper can effectively improve the machining quality.

Creation of New Types of Power Supply and Life Support Systems for Spacecraft Powered by a Solar Panel

The work of power supply and life support systems of spacecraft is completely based on consumables, delivered from Earth, the mass, and dimensions of which increase in direct proportion to the duration of the space expedition and the number of crew members. Therefore, today a power supply system is used on board a spacecraft that provides onboard electrical energy for the operation of all on-board equipment (engine, control, communications, and heating systems) by generating direct electric current using a generator, converting chemical energy into electrical energy, using fuel cells, powered by supercritical liquid hydrogen and liquid oxygen, delivered from Earth. The life support system, used today on the spacecraft, includes: system for regenerating water from atmospheric humidity condensate in a spacecraft cabin, a water regeneration system from urine, system of generating oxygen and hydrogen during the electrolysis of water in microgravity conditions, a system for utilizing carbon dioxide, removing harmful micro impurities, operating at the expense of internal resources spacecraft during space flight. Thus, the task arises of developing new types of power supply and life support systems, including the development of new and improvement of existing technologies for continuous charging of spacecraft fuel cells with hydrogen and oxygen, generating onboard electricity without the use of “Earth tanks” with supercritical liquid hydrogen and liquid oxygen, improvement of existing oxygen and hydrogen generation systems, regeneration of water from condensate of atmospheric moisture and waste products of astronauts, removal of harmful micro impurities and cultivation of rapidly multiplying microalgae on the spacecraft during a long space flight. The article presents a new type of power supply and life support systems for spacecraft, powered by a solar panel, which includes the developed new technologies: an oxygen and hydrogen gas generator, which makes it possible to economically and easily separately produce oxygen, hydrogen and drinking water to enrich the atmosphere with oxygen and replenish the drinking supplies of the spacecraft cabin, continuously charge the fuel cells of the spacecraft with hydrogen and oxygen, produced for the uninterrupted generation of onboard electricity; a separator for purification of technical wastewaters from harmful solid inclusions and pathogenic microbes and obtaining drinking water from them, regeneration of drinking water from urine, excreted by astronauts, in quantities sufficient for consumption of this water by astronauts during a long space flight; a concentrator that receives a solution with microalgae cells from a space photo bioreactor, growing microalgae under weightless conditions, which utilizes carbon dioxide released during the breathing of astronauts, produces oxygen to enrich the atmosphere of the spacecraft cabin with oxygen through photosynthesis. A concentrator permits to obtain a high-quality concentrate of cells of rapidly multiplying microalgae and supplement the crew's diet by the biggest part of this concentrate, and to replenish the space photo bioreactor with the remainder of the concentrate and nutrient solution in order to obtain enough biomass for a long space flight.

Investigation of microgravity vortex phase separator for spacecraft liquid amine CO2 removal system

Spacecraft cabin atmosphere revitalization, more specifically CO2 removal, is a key technology to pursue long-duration, crewed space missions, such as the ones to the Moon and Mars. The ISS currently uses the Carbon Dioxide Removal Assembly (CDRA) as the primary system that employs solid sorbent (zeolite) to remove CO2 from cabin air. However, CDRA cannot meet high reliability and low maintenance requirements. Liquid sorbents may be used as an alternative to solid sorbents and are estimated to attain 65 % less power, weight, and volume than solid based CO2 scrubbers. Liquid amines (liquid sorbent) are currently being researched by NASA for CO2 capture, however their implementation for space applications depends on an effective gas-liquid separation method under microgravity conditions. The Vortex Phase Separator (VPS) offers a new approach for a liquid amine CO2 removal system, and initial investigation of the prototype VPS system demonstrated up to 90.3 % CO2 removal from a humid CO2 stream at 1.47 l/min flow rate. Tests were conducted to determine the CO2 removal efficiency considering several operating parameters, including the liquid amine flow rate, initial fill (charge) level, and temperature; CO2 flow rate; extended-time operation; and CO2-amine pre-mixing length. Results provided key insights on design, operation, and performance aspects of a subscale system, and demonstrated the feasibility of the microgravity VPS for liquid amine CO2 removal system as an alternative, novel spacecraft air revitalization approach.

Creation of New Types of Power Supply and Life Support Systems for Spacecraft Powered by a Solar Panel

The work of power supply and life support systems of spacecraft is completely based on consumables, delivered from Earth, the mass, and dimensions of which increase in direct proportion to the duration of the space expedition and the number of crew members. Therefore, today a power supply system is used on board a spacecraft that provides onboard electrical energy for the operation of all on-board equipment (engine, control, communications, and heating systems) by generating direct electric current using a generator, converting chemical energy into electrical energy, using fuel cells, powered by supercritical liquid hydrogen and liquid oxygen, delivered from Earth. The life support system, used today on the spacecraft, includes: system for regenerating water from atmospheric humidity condensate in a spacecraft cabin, a water regeneration system from urine, system of generating oxygen and hydrogen during the electrolysis of water in microgravity conditions, a system for utilizing carbon dioxide, removing harmful micro impurities, operating at the expense of internal resources spacecraft during space flight. Thus, the task arises of developing new types of power supply and life support systems, including the development of new and improvement of existing technologies for continuous charging of spacecraft fuel cells with hydrogen and oxygen, generating onboard electricity without the use of “Earth tanks” with supercritical liquid hydrogen and liquid oxygen, improvement of existing oxygen and hydrogen generation systems, regeneration of water from condensate of atmospheric moisture and waste products of astronauts, removal of harmful micro impurities and cultivation of rapidly multiplying microalgae on the spacecraft during a long space flight. The article presents a new type of power supply and life support systems for spacecraft, powered by a solar panel, which includes the developed new technologies: an oxygen and hydrogen gas generator, which makes it possible to economically and easily separately produce oxygen, hydrogen and drinking water to enrich the atmosphere with oxygen and replenish the drinking supplies of the spacecraft cabin, continuously charge the fuel cells of the spacecraft with hydrogen and oxygen, produced for the uninterrupted generation of onboard electricity; a separator for purification of technical wastewaters from harmful solid inclusions and pathogenic microbes and obtaining drinking water from them, regeneration of drinking water from urine, excreted by astronauts, in quantities sufficient for consumption of this water by astronauts during a long space flight; a concentrator that receives a solution with microalgae cells from a space photo bioreactor, growing microalgae under weightless conditions, which utilizes carbon dioxide released during the breathing of astronauts, produces oxygen to enrich the atmosphere of the spacecraft cabin with oxygen through photosynthesis. A concentrator permits to obtain a high-quality concentrate of cells of rapidly multiplying microalgae and supplement the crew's diet by the biggest part of this concentrate, and to replenish the space photo bioreactor with the remainder of the concentrate and nutrient solution in order to obtain enough biomass for a long space flight.

Quiet Spacecraft Cabin Ventilation Fan Development: Motivation and Context

It is important to control acoustical noise aboard crewed space vehicles and space habitats to provide a satisfactory environment for voice communications, alarm audibility, and restful sleep, and to minimize the risk for hearing loss and annoyance. As with most noise control efforts, it is best to control the noise at the source, and for spaceflight vehicles these are typically the fans associated with the Environmental Control and Life Support system. These include cabin ventilation fans and intermodule ventilation fans, among others. Throughout the history of crewed spaceflight, there have been issues with noise from ventilation fans, going back to Apollo. And, with the spaceflight vehicles and habitats currently being developed, there are again concerns with noise from ventilation fans. To address this problem, NASA is working to leverage the technology developed in its Aeronautics Research Mission Directorate, specifically at the Glenn Research Center, to design highly efficient and quiet fans for reducing community noise levels from civilian aircraft. This paper will discuss the need for transfer of this technology to spaceflight use, and will discuss the potential benefits, which are significant and will be crucial for the successful development and operations of future spaceflight vehicles, space suits, and habitats.

Quiet Spacecraft Cabin Ventilation Fan: Vibration Measurements Results

Quiet, efficient fans with minimal vibrations are needed to maximize the mechanical life of atmospheric revitalization system fans used for human life support systems for long duration space exploration missions. Several metal spacecraft cabin ventilation fan prototypes have been designed, built, and tested at the NASA Glenn Research Center Acoustical Testing Laboratory. Tests performed in 2021 of the first prototype of the metal fan measured vibrations greater than desired at design point speed and backpressure conditions. To try to reduce those vibrations, a second prototype of the fan design was developed which included a new lighter rotor with a tighter balance tolerance, a new collet to attach the rotor to the motor shaft more securely and repeatably, and a new bracket to center and hold the motor in the fan centerbody more precisely. The second prototype of the fan was tested in 2023 and the vibrations were measured with the fan operating at design point speeds in isolation but not throttled to design point back pressure conditions since it was not installed with inlet and exhaust ducting. Peak vibration was reduced from 4 mm/s to 1 mm/s. This paper is part of a series of reports documenting the performance of the prototype fan.

Quiet Spacecraft Cabin Ventilation Fan: Wake Measurements Results

A spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and two copies of the fan assembly were fabricated - designated as Quiet Space Fan. Both fans were tested for aerodynamic performance and acoustic levels in the NASA Glenn Research Center Acoustical Testing Laboratory. A new test rig for small axial flow fans was designed to accommodate the instrumentation and back-pressure adjustments. Measurements acquired were - static pressures for measuring performance, a 72-channel in-duct microphone array, external microphone measurements for acoustics, and inter-stage hot wire measurements of the fan wake. This report documents the wake velocity and turbulence measurements as part of a series of reports.

A Study of Preliminary Design Methods for Low Noise Fans

Engineers need theory and computer codes to help them design quiet and efficient fans. A fast method to identify low-noise stator vane counts that might minimize tone noise for axial ducted fans has been developed. The analysis begins with a preliminary aerodynamic fan design. Duct acoustic and rotor-stator interaction theories are combined to predict the set of cut-on circumferential modes that are expected to be generated and propagate through the fan duct. By predicting the number of cut-on circumferential modes for each vane count, a set of low-noise vane counts for a given rotor and duct design can be identified. This method was used to design the stator set for NASA's spacecraft cabin ventilation fan, in order to minimize tone noise generated by rotor-stator interaction at the first three blade passing frequency harmonics. This method was also applied to three other research fans that NASA uses for aeroacoustics research for comparison. This technique can be used to include acoustic design criteria early in the design of an axial fan and provide valuable information to guide the final design of quiet fans.

Quiet Spacecraft Cabin Ventilation Fan: Acoustic Measurements Results

A spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and two copies of the fan assembly were fabricated - designated as Quiet Space Fan. Both fans were tested for aerodynamic performance and acoustic levels in the NASA Glenn Research Center Acoustical Testing Laboratory. A new test rig for small axial flow fans was designed to accommodate the instrumentation and back-pressure adjustments. Measurements acquired were - static pressures for measuring performance, a 72-channel in-duct microphone array, external microphone measurements for acoustics, and inter-stage hot wire measurements of the fan wake. This report documents the acoustic measurements as part of a series of reports.

Quiet spacecraft cabin ventilation fan: aerodynamic measurements results

A metal spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and two copies of the fan assembly were fabricated. Both fans were tested for aerodynamic performance and acoustic levels in the NASA Glenn Research Center Acoustical Testing Laboratory. A new test rig for small axial flow fans was designed to accommodate the instrumentation and back-pressure adjustments. Measurements acquired were from: static pressures for measuring performance, a 72-channel in-duct microphone array, external microphone measurements for acoustics, and inter-stage hot wire measurements of the fan wake. This report documents the aerodynamic measurements as part of a series of reports.

ELUCIDATION OF CELLULAR MECHANISMS OF AUTOPHAGY INVOLVEMENT IN PLANT ADAPTATION TO MICROGRAVITY CONDITIONS

It was shown that clinostating conditions induce autophagy without increasing of programmed cell death (PCD) index in the epidermal cells of the root apex of A. thaliana seedlings. After the phase of activation of autophagy, its regulatory weakening occurs, which probably indicates adaptive changes to the conditions of clinostating. The induction of autophagy correlates with an increase in the expression levels of atg8 genes, some of which (atg8e and atg8i) may be involved in the implementation of autophagy under the simulated microgravity conditions. The transcriptional activity of cytoskeleton genes involved in the implementation of stress-induced autophagy, in particular α- and β-tubulin genes, was analyzed. Joint expression of α- and β-tubulin genes and atg8 under the simulated microgravity conditions was revealed. These results illustrate the role of the cytoskeleton in the development of microgravity-induced autophagy and make it possible to identify genes specific to this type of stress. The induction of autophagy and PСD was studied under the action of gamma irradiation as a concomitant factor of space flights, as well as under the combined action of acute irradiation and clinostating. Gamma irradiation in doses equivalent to those in the spacecraft cabin (1 - 6 Gy) induced dose-dependent changes in the topology and cytogenetic state of the root apical meristem, as well as slightly inhibited of the early plant development. In the meristem, heterogeneity increased, PCD indexes, mainly proliferative death and autophagy, increased. With the combined action of gamma irradiation (2 Gy) and clinostating, the density of autophagosomes in the epidermal cell root apices of 6-day-old seedlings increased (24 hours after irradiation), and after 4 days it decreased, compared to the non-irradiated control.

Modelling and analysis of metal flowing behaviors in constraining ring rolling of tapered ring with thin wall and three high ribs

Tapered ring with thin wall and three high ribs (TRTWTHR), showing complicated geometry (wall thickness is less than 4 mm and rib height exceeds 20 mm), is extensively utilized to fabricate the critical structural parts of aerospace equipment such as spacecraft cabin, rocket body and fuel tank because of light weight and high carrying capacity. How to fabricate TRTWTHR with high performance is a critical problem that aerospace area needs to solve. In this work, constraining ring rolling (CRR) technique is first adopted to form TRTWTHR. However, unreasonable metal streamlines (UMS) and uncoordinated growth of three ribs easily occur in CRR of TRTWTHR, which makes the forming quality of TRTWTHR difficult to be controlled. Faced with this difficulty, an analytical model that can predict UMS and the height of three ribs in CRR of TRTWTHR is established so as to guide the process design of CRR. Subsequently, the reliability of the established analytical model and the feasibility of CRR of TRTWTHR are confirmed by FE simulation and experiment. Then, using the established analytical model, the window of UMS occurring relevant to the tapered angle of TRTWTHR and the location of the rib of middle end is developed. Finally, three uncoordinated growth modes among three ribs are found when the width of three ribs is identical and UMS do not occur, and the mechanisms of three uncoordinated growth modes are revealed.

Base placement optimization of a mobile hybrid machining robot by stiffness analysis considering reachability and nonsingularity constraints

The mobile hybrid machining robot has a very bright application prospect in the field of high-efficiency and high-precision machining of large aerospace structures. However, an inappropriate base placement may make the robot encounter a singular configuration, or even fail to complete the entire machining task due to unreachability. In addition to considering the two constraints of reachability and non-singularity, this paper also optimizes the robot base placement with stiffness as the goal to improve the machining quality. First of all, starting from the structure of the robot, the reachability and nonsingularity constraints are transformed into a simple geometric constraint imposed on the base placement: feasible base placement area. Then, genetic algorithm is used to search for the base placement with near optimal stiffness (near optimal base placement for short) in the feasible base placement area. Finally, multiple controlled experiments were carried out by taking the milling of a protuberance on the spacecraft cabin as an example. It is found that the calculated optimal base placement meets all the constraints and that the machining quality was indeed improved. In addition, compared with simple genetic algorithm, it is proved that the feasible base placement area method can shorten the running time of the whole program.

An HRA Model Based on the Cognitive Stages for a Human-Computer Interface in a Spacecraft Cabin

HRA (Human Reliability Analysis) can be seen as a symmetric problem, as it is mainly reflected in two aspects of failure and success. Human error is the most common accident in industrial systems; furthermore, an astronaut is in a very complex environment, and coupled with weightlessness, it is easy to cause human error. For this reason, this paper took the human-computer interface in a spacecraft cabin as the background, and based on the literature, questionnaire inquiry, and the division of three cognitive processes during the interaction between the astronaut and human, a computer interface was determined. This paper proposed a human reliability influencing factors system of different cognitive phases for the human-computer interface in a spacecraft cabin, a task analysis tree with a symmetry of success and failure, an HRA model with symmetry of failure and success based on cognitive stages, and Game Theory and Fuzzy Center of Gravity Method, and obtained influencing factors weights of three cognitive stages. By simulating an experiment, the trend of error probability curves shows the rationality of the human reliability method. Finally, an example was illustrated, and the analysis process of the example demonstrates that an HRA model with symmetry provides a feasible analysis process and method for the cognitive reliability of the spacecraft cabin human-computer interface interaction. The research achievements in this paper can provide theoretical guidance to improve human error root reason analysis, an analysis basis of how to improve influencing factors level, and provide a HRA method based on cognitive stages for the human-computer interaction process in a spacecraft cabin.

Highlights of aeroacoustic tests of a metal spacecraft cabin ventilation fan prototype

A metal spacecraft cabin ventilation fan suitable for aerodynamic and acoustic ground tests was designed and tested in the NASA Glenn Research Center Acoustical Testing Laboratory. The fan design featured a low-noise blade-vane count that was chosen to reduce the rotor-stator interaction tone noise. The fan was throttled through its operating range, and results indicated that the measured aerodynamic and acoustic performance was in good agreement with predictions. Recommendations for further research of quiet high-performance fans intended to support long duration human space exploration missions are offered. This small fan aerodynamic and acoustic test rig and the NASA Glenn Acoustical Testing Laboratory are valuable resources available for supporting NASA's aeronautics research and space exploration missions.

An accurate calibration method of a combined measurement system for large-sized components

Large-sized components with numerous supports are essential in advanced manufacturing. Efficient product quality control requires accurate three-dimensional (3D) measurements and error control. For 3D shape and spatial position measurements of the key local features on the support mounting surface, we propose an accurate measurement method combining a global laser tracker, local scanning system, and mobile robot system comprising an industrial robot and a mobile platform. To enhance the measurement accuracy, an accurate calibration method was introduced based on prior knowledge which establishes correlation constraints between local and global calibration. The local calibration method, including rail orientation and extrinsic parameters calibration based on a multi-dimensional combined collaboration target, achieves accurate calibration of both rail orientation and extrinsic parameters. Additionally, the enhanced global calibration method based on multi-dimensional cooperative calibrators constructs correlation constraints among global control points and provides an accurate global measurement field. We constructed a combined measurement system and conducted large-scale measurement experiments. As shown by the accuracy verification results of the proposed system, the maximum and mean measurement errors decreased from 0.142 and 0.132 mm to 0.111 and 0.095 mm within 8 m, respectively, which is highly accurate. Moreover, the large-scale scanning instance of a large-sized spacecraft cabin has also demonstrated that the developed method can significantly expand the measurement range as well as improve the measurement flexibility.

Sensitivity analysis of the integrated AHP-TOPSIS and CRITIC-TOPSIS method for selection of the natural fiber

Selection of natural fibers in composites for usage in aircraft or spacecraft cabin interior requires determining the performance scores for various criteria specified by material requirements. Because of the widespread available alternatives and their various criteria, it becomes a Multi criteria Decision Making (MCDM) problem and requires statistical methods to carry out the selection process. However, the selection process of the most suitable natural fiber can provide different results depending on their assigned weightages and sensitivity to the variation of that weightages. The main contribution of this study lies in analyzing the sensitivity of the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method for subjective weightage method: Analytic Hierarchy Process (AHP) and objective weightage method: CRiteria Importance Through Inter-criteria Correlation (CRITIC) for the selection of the best natural fiber among twelve alternatives by eliminating the rank reversal problem. This study will assist the researchers in this field to focus on developing the best possible natural fiber reinforced polymer composites for applications in the aerospace cabin interior.

Metabolic response of Chlorella vulgaris to a transient thermal environment for supporting simultaneous air revitalization and thermal control in a crewed habitat

Implementing multifunctional bioregenerative technologies may provide mission carbon loop closure while simultaneously addressing multiple environmental control and life support system requirements. This paper proposes using water-based algal medium for thermal control of the spacecraft cabin, while taking advantage of the algae's photosynthetic activity for air revitalization. Consequently, this could expose the algal culture to transient thermal environments fluctuating between +4 °C and +30 °C, in the span of minutes, reflecting the operation of the International Space Station (ISS) internal thermal control and cabin system. This paper presents an initial investigation of the metabolic response of Chlorella vulgaris to transient environmental temperatures, reflecting temperature ranges and cycling frequency of the ISS cooling loop (+9 °C to +27 °C, 30 min). The constant 19 °C control represented the time-averaged temperature of the cycled condition. Growth and acclimation were observed in both tested conditions through pH, dissolved oxygen, optical density, and photosynthetic quantum yield measurements. However, there was significant reduction in the oxygen production rate, measured pH, and optical density for the cycled temperature condition when compared to the control (cycled temperature = 0.95 gO2 L−1 d−1, pH = 6.75, OD = 0.05; control = 1.17 gO2 L−1 d−1, pH = 8.20, OD = 0.08). No significant reduction in growth rate or photosynthetic quantum yield were recorded between the two tested conditions. Growth rate of the cycled temperature condition reflected those of psychrotolerant algae, suggesting some amount of culture acclimation to the rapidly dynamic environment. Results suggest that while C. vulgaris was viable within the tested temperature environment reflecting the ISS thermal control loop and cabin, there was a measurable reduction in the oxygen production rate.

IVA spacesuit for commercial spaceflight - Upper body motion envelope analysis

This paper introduces a new, preliminary physical ergonomics model for spacecraft cabin and cockpit architecture and for control systems layout conceptualization. The research was executed during a year-long collaboration between the Florida Institute of Technology's Human Spaceflight Laboratory and Embry-Riddle Aeronautical University's Spacesuit Utilization of Innovative Technology Laboratory. It focused on physical ergonomics using an adjustable intravehicular activity Terra Spacesuit manufactured by Final Frontier Design (FFD). The main goal of this laboratory research was to generate an FFD spacesuit specific reference model of reach envelope. The model provides concrete numerical data about potential spaceflight participants' or astronauts' upper body motion, which can be used to improve spacecraft interior design. The reach envelope was mapped using an IR motion tracking system in unsuited, suited unpressurized, and suited pressurized configurations. The resulting model is presented as a geometric area accessible to all test subjects participating in this research. Although this experimental model is based on training spacesuit hardware and operated under lower (1.5 psid) than usual (3.5 psid) operating pressure, it demonstrates the physical ergonomic limitations of wearing an Intra Vehicular Activity pressurized suit. This model further helps spacecraft cabin, flight deck or cockpit architects to identify the optimum internal layout of the vehicle, placement of the control and display components. Control function activation during specific phases of the spaceflight may require either unpressurized or pressurized spacesuit operations. The accessibility of the control input systems is the primary factor in their placement inside the cockpit. More importantly, the vehicle controls, system input devices, and displays should be not only within reach, but also within an executable/operational position and configuration, or work envelope.

An equivalent shape-preserving clipping method for the control spectrum to avoid over-testing of triaxial random vibration

Triaxial vibration tests can realistically simulate the vibration environment suffered by products. In this paper, an equivalent shape-preserving clipping method for the control spectrum is proposed to avoid over-testing of triaxial random vibration. Considering synchronous response control of the triaxial vibration, the correlative triaxial random load identification model is built to implement the designated triaxial random vibration test. Then, with the goal of avoiding over-testing of triaxial random vibration, a clipping method following four kinds of clipping criteria is studied based on stress equivalence to the key components. Further, to be consistent with the key indicators of the control spectrum in the current uniaxial vibration test specification, a shape-preserving regulation is proposed for determining the triaxial vibration control spectrum. Finally, the effectiveness of the proposed method is verified by taking a typical spacecraft cabin as the example.