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Human space exploration to date has been limited to low Earth orbit and the moon. The International Space Station (ISS) provides a unique opportunity for researchers to prove out the technologies that will enable humans to safely live and work in space for longer periods and venture farther into the solar system. The ability to manufacture parts in-space rather than launch them from earth represents a fundamental shift in the current risk and logistics paradigm for human space exploration. The purpose of this mission is to prove out the fused deposition modeling (FDM) process in the microgravity environment, evaluate microgravity effects on the materials manufactured, and provide the first demonstration of on-demand manufacturing for space exploration.

In 2014, NASA, in cooperation with Made in Space, Inc., launched a 3D printer to the ISS with the goal of evaluating the effect of microgravity on the fused deposition modeling (FDM) process and prove out the technology for use on long duration, long endurance missions where it could leveraged to reduce logistics requirements and enhance crew safety by enabling a rapid response capability. This paper presents the results of testing of the first phase of prints from the technology demonstration mission, where 21 parts where printed on orbit and compared against analogous specimens produced using the printer prior to its launch to ISS.

Mechanical properties, dimensional variations, structural differences and chemical composition for ground and flight specimens are reported. Hypotheses to explain differences observed in ground and flight prints are also developed. Phase II print operations, which took place in June and July of 2016, and ground-based studies using a printer identical to the hardware on ISS, will serve to answer remaining questions about the phase I data set. Based on Phase I analyses, operating the FDM process in microgravity has no substantive effect on the material produced.

Demonstrates that there is no discernable, engineering significant effect on operation of FDM in microgravity. Implication is that material characterization activities for this application can be ground-based.

Summary of results of testing of parts from the first operation of 3D printing in a microgravity environment.

On a microgravity condition, a motion of soliton might be subject to a microgravity-induced motion. There is no theory so far to study the effect of air density and gravity on the motion property. Here, the author considers the air as discrete molecules and a motion of a soliton is modeled based on He’s fractal derivative in a microgravity space. The variational principle of the alternative model is constructed by semi-inverse method. The variational principle can be used to establish the conservation laws and reveal the structure of the solution. Finally, its approximate analytical solution is found by using two-scale method and homotopy perturbation method (HPM).

The author establishes a new fractal model based on He’s fractal derivative in a microgravity space and its variational principle is obtained via the semi-inverse method. The approximate analytical solution of the fractal model is obtained by using two-scale method and HPM.

He’s fractal derivative is a powerful tool to establish a mathematical model in microgravity space. The variational principle of the fractal model can be used to establish the conservation laws and reveal the structure of the solution.

The author proposes the first fractal model for the soliton motion in a microgravtity space and obtains its variational principle and approximate solution.

This paper presents a new multi‐channel temperature measurement system (MCTMS) with small size, light weight and low power consumption for the microgravity fluid experiment of drop Marangoni migration on SZ‐4 spaceship, a test module of the manned space mission of China.

The MCTMS, with a commercial‐off‐the‐shelf (COTS) component monolithic thermocouple amplifier with cold junction compensation AD595, is designed to measure temperature gradient field of up to 6 type T thermocouples Cu‐Constantan for microgravity fluid experiment. Through an analog multiplexer, the very small signal amplitude of the six‐channel temperatures can be acquired and amplified by the same monolithic thermocouple amplifier to retain the consistency of the six channels. A fully mission analysis and evaluation on the COTS component was taken into account before it was used in the thermal and radiation environment of space.

Using the COTS component in space can increase the system performance and considerably reduce the size, weight, power consumption and the overall complexity of the system. The measurement resolution of the MCTMS reaches 0.1°C because of the utilization of the COTS with high performance. In addition, the transfer function of the AD595 was deduced for type T thermocouples.

This paper suggests an easy way of measuring temperature for microgravity fluid experiment on spacecraft. Using a COTS component on spacecraft, also, is a new practical case study, which is more suitable for on‐board implementation. The MCTMS, presented in this work, has run in‐orbit successfully on SZ‐4 spaceship and the experiment result in space is reported.

Reducing inequity in accessing healthcare among rural and remote populations remains a problem. Internationally, eHealth is now touted as a potential solution, with a range of diverse approaches and impacts. Yet, the equity gains of implementing eHealth are often not realized due to a lack of effective strategies for citizen participation. The purpose of this paper is to present the background to, and results of, a multidisciplinary eHealth assistance project in a remote region of the Brazilian Amazon, highlighting the importance of citizen participation within planning processes.

The project was conducted in three phases – pre‐mission, mission, and post‐mission. Discussions were held between health teams and local community leaders, and were coordinated by government health organizations in partnership with the Amazon State University. A multidisciplinary team visited five remote communities in the Brazilian Amazon, where participants underwent clinical assessment using eHealth technologies within pharmacy, cardiology, dermatology, and/or odontology. Analysis and second opinion were provided by relevant specialists and the results were delivered electronically to local healthcare teams.

A total of 111 patients were evaluated with an average age of 54 years. There were several important findings following specialist second opinion, which improved the quality of care they received. These comprise identifying drug interactions and patients requiring further investigation for cardiological and dermatological complaints, including suspected malignancy.

Due to a breakdown in communication, data from the post‐mission phase are lacking, particularly regarding treatment outcomes. Furthermore, the authors did not perform an analysis of cost‐effectiveness. If eHealth technologies are to become part of routine clinical practice it is important that the financial implications are acceptable.

This project demonstrates how equity can be designed for with a multidisciplinary approach to eHealth activities in rural and remote environments within Brazil. Such activities typically focus on one particular area, yet primary healthcare facilities see patients with a variety of problems.

The authors performed FACET (Investigation on Mechanism of Faceted Cellular Array Growth) experiments under long duration microgravity on the International Space Station (ISS) in 2010. The temperature and concentration distributions in the melt during the growth were precisely measured with high spatial resolution. Negative temperature gradient as well as negative concentration gradient ahead of the S/L interface can be expected to be the driving forces of the morphological instability. It is evident that the conventional model based on the frozen temperature approximation is insufficient to explain the growth mechanism of the faceted cellular array.

The quality of crystals grown from melt depends on the flow field in the melt. To simulate melt conditions, a finite element analysis is performed on flow in a heated cavity under the driving forces of natural convection, thermocapillary effects and rotation. In addition, the gravity field is modulated to simulate a microgravitational environment. The purpose for conducting this research is to determine whether the use of baffles can effectively reduce convection and suppress temperature oscillations. The results show that the baffle is able to suppress convection and reduce the amplitude of the temperature oscillations when placed perpendicular to the modulation direction. Under crystal and crucible rotation, the results with and without baffles are similar. In all cases, baffles did not induce temperature oscillations. From this study, it can be concluded that the effects of baffles on the flow behaviour depends greatly on the direction of gravity modulation and frequency.

Free and moving boundary problems require the simultaneous solution of unknown field variables and the boundaries of the domains on which these variables are defined. There are many technologically important processes that lead to moving boundary problems associated with fluid surfaces and solid‐fluid boundaries. These include crystal growth, metal alloy and glass solidification, melting and flame propagation. The directional solidification of semi‐conductor crystals by the Bridgman—Stockbarger method^1,2 is a typical example of such a complex process. A numerical model of this growth method must solve the appropriate heat, mass and momentum transfer equations and determine the location of the melt—solid interface. In this work, a Chebyshev pseudospectral collocation method is adapted to the problem of directional solidification. Implementation involves a solution algorithm that combines domain decomposition, a finite‐difference preconditioned conjugate minimum residual method and a Picard type iterative scheme.

The purpose of this paper is to investigate the time optimal trajectory of the multi-tethered robot (MTR) on a large spinning net structures in microgravity environment.

The MTR is a small space robot that uses several tethers attached to the corner-fixed satellites of a spinning net platform. The transition of the MTR from a start point to any arbitrary designated points on the platform surface can be achieved by controlling the tethers’ length and tension simultaneously. Numerical analysis of trajectory optimization problem for the MTR is implemented using the pseudospectral (PS) method.

The globally time optimal trajectory for MTR on a free-end spinning net platform can be obtained through the PS method.

The analysis in this paper is limited to a planar trajectory and the effects caused by attitude of the MTR will be neglected. To make the problem simple and to see the feasibility in the general case, in this paper, it is assumed there are no any limitations of mechanical hardware constraints such as the velocity limitation of the robot and tether length changing constraint, while only geometrical constraints are considered.

The optimal solution derived from numerical analysis can be used for a path planning, guidance and navigation control. This method can be used for more efficient on-orbit autonomous self-assembly system or extravehicular activities supports which using a tether-controlled robot.

This approach for a locomotion mechanism has the capability to solve problems of conventional crawling type robots on a loose net in microgravity.

This article has been withdrawn as it was published elsewhere and accidentally duplicated. The original article can be seen here: 10.1108/17488840610639681. When citing the article, please cite: Xiujie Jiang, Huixian Sun, Xiaomin Chen, Zhihua Wang, Li Zhang, Daxing Wang, (2006), “Utilization of a COTS component in temperature measurement system for microgravity fluid experiment on SZ-4 spaceship”, Aircraft Engineering and Aerospace Technology, Vol. 78 Iss: 1, pp. 45 - 49.

The purpose of this study is to explore the applications of 3D printing in space sectors. The authors have highlighted the potential research gap that can be explored in the current field of study. Three-dimensional (3D) printing is an additive manufacturing technique that uses metallic powder, ceramic or polymers to build simple/complex parts. The parts produced possess good strength, low weight and excellent mechanical properties and are cost-effective. Therefore, efforts have been made to make the adoption of 3D printing successful in space so that complex parts can be manufactured in space. This saves a considerable amount of both time and carrying cost. Thereof the challenges and opportunities that the space sector holds for additive manufacturing is worth reviewing to provide a better insight into further developments and prospects for this technology.

The potentiality of 3D printing for the manufacturing of various components under space conditions has been explained. Here, the authors have reviewed the details of manufactured parts used for zero-gravity missions, subjected to onboard international space station conditions and with those manufactured on earth. Followed by the major opportunities in 3D printing in space which include component repair, material characterization, process improvement and process development along with the new designs. The challenges like space conditions, availability of power in space, the infrastructure requirements and the quality control or testing of the items that are being built in space are explained along with their possible mitigation strategies.

These components are well comparable with those prepared on earth which enables a massive cost saving. Other than the onboard manufacturing process, numerous other components as well as a complete robot/satellite for outer space applications were manufactured by additive manufacturing. Moreover, these components can be recycled onboard to produce feedstock for the next materials. The parts produced in space are bought back and compared with those built on earth. There is a difference in their nature, i.e. the flight specimen showed a brittle nature, and the ground specimen showed a denser nature.

This review discusses the advancements of 3D printing in space and provides numerous examples of the applications of 3D printing in space and space applications. This paper is solely dedicated to 3D printing in space. It provides a breakthrough in the literature as a limited amount of literature is available on this topic. This paper aims at highlighting all the challenges that additive manufacturing faces in the space sector and also the future opportunities that await development.