Japanese/english


RESEARCH ON ADVANCED DEPLOYABLE STRUCTURE

[March 2017]

We proceed this research as part of the project "Formation of Center for Research and Development of Advanced Deployable Structure Pioneering Innovative Space Science" that is led by Prof. Hiraku Sakamoto of Tokyo Institute of Technology, and supported by Coordination Funds for Promoting AeroSpace Utilization, MEXT. Prof. Yamazaki and Prof. Miyazaki are co-researcher of this project. The project is named ORIGAMI (ORganization of research Group on Advanced deployable Membrane structure for Inovative Science). You can see the detail of the activity at the web site of ORIGAMI project http://www.origami.titech.ac.jp/. In this page, we would like to introduce you our motivation to participate in this project and what we aim in this project.


Background

As written in the top page of research information, The researchers on space structure, especially next generation light-weight space structure such as membranes have been quite active since the middle of 2000's. Those research include the ones that resulted in the sccuess of the space mission such as IKAROS and SIMPLE. The fact that the research has been active means that much budget has been spent. However, how many scientists in Japan can answer with firm proof the question "What kind of thing is the next generation space structure? When will it be realized?" In fact, we are afraid that our laboratory can say very few things with proof even though we can say something with our imagination. Then, we feel that we, scientists, should achieve a specific outcome by now because reasonable budget has been spent for the research on space structure.

On the other hand, the scientists who try to utilize 3U - 6U CubeSat for their research have been icreasing in other countries, i.e. the research in space is rapidly getting active. This is because many scientists recognize that the technology of the bus system of CubeSat has improved so that it deserves to be used for research. If such a stream grows, they will possibly answer the above question with the result of the CubeSats as the proof, and they apply the resutls to small or large satellites, and show something up and say "This is the one that has been told the next generation space structure".

This is not only available for space structure. Currently, research on space engineering that can not be closed in the laboratory in university or can note be closed on the ground any more. The research is conducted in real space. This is the world trend.

Looking out at the domestic situation, less than expected are the scientists who try to research in space by using the space platform such as the international space station, or by developing nano-satellites by theirselves. Comparing with overseas research, we wonder whether Japan can keep the level of the research equal against overseas research.

Howeever that may be, it seems not to be often that overseas scientists obtain excellent result by using their CubeSat or other space devices. The number of launched CubeSats has rapidly increased since 2013, but there are many CubeSats that did not work (Only 50% of launched CubeSats worked in space?). We can buy the CubeSat whole system or the components through internet now, but it is important to integrate the system and implement the on-board software with assumption of various cases (worst case) in order to make the satellite work well in space.

Also in Japan, there are not so many nano-satellites that scceeded the mission though lots of nano-satellites were developed by universities and launched. There seems to be rather many satellites that did not work well in space.

In the result, there has been increasing the accusing voice "Never scatter space debris (space junk)!" toward nano-satellite communities.

Considering such situation, our laboratory are going to contribute

  • to achieve research results in space as before,
  • to encourage scientists of space engineering, especially young scientists to make their research into space and achieve resutls,
  • to build a mechanism that whole scientists can create excellent results by having high-level discussions between the scientists of space structural engineering including us,
  • to make something like a roadmap of space structure and to proceed the research looking ahead to the target for achieving world-class results.
We think the followings are necessary to promote the above:
  1. To show the (young) scientists around us "how to achieve results by conducting the research on space structure in space"
  2. To draw a roadmap
  3. To provide to the scientists some place to make severe discussion about their own research, to stimulate each other, to create collaborateve research results in space as well as the place for exchange and awareness between young scientists including students like ALSS
  4. To disscuss about what we should do to make the satellite (or experimental equipments in space) in order to achieve research results in space, and to structure an organization (mechanism) to make the success rate high.
We have thought to realize #1 and #2 through ORIGAMI project, and applied the fund of MEXT with Prof. Sakamoto. Fortunately, our proposal was adopted and ORIGAMI project started in the end of FY2014.


Research

You can see the objectives of this project in the web site of ORIGAMI project. In this project, our laboratory is seeking for "organizing the network for research and development where young scientists can create advanced deployable space structure that will be necessary to achieve innovative space science". As mentioned in "Background", we are going to do the following two subjects to achieve the above objective:

  1. To show the (young) scientists around us "how to achieve results by conducting the research on space structure in space"
  2. To draw a draft ot the research roadmap of space structure and discuss about it with other scientists
To achieve the first one, ORIGAMI project team takes the following approach: "we research on specific examples, configure the scheme to verify the examples in space, and disclose the whole process of our activity". As for "specific example", we chose "research on boom-membrane integrated deployable structure" and "development of design and verification method of deployable space structure by fusion of numerical analysis and experimmental/flight data". As for the scheme of space verification, we chose "preliminary verification by ground experiment and micro-gravity experiment using airplane&, and "piggy back launnch of 3U CubeSat from ISS or other launch vehicle".

TokyoTech team leads the research on boom-membrane integrated deployable structure and its space verification by 3U CubeSat, and WEL Research and Sakase Ad-Tech support the development of the component and the system. Off course, our laboratory participates in the discussion about the design and development of the CubeSat, and we try to manufacture "a satellite certainly working well". Prof. Yamazaki leads "development of design and verification method of deployable space structure by fusion of numerical analysis and experimmental/flight data". The ground experiment and aircraft micro-gravity experiment are conducted by both TokyoTech and Our laboratory. Our laboratory is resonsible for aircraft experiment. We will make various deployable membrane structure by ourselves. "Boom-Membrane Integrated Deployable Structure" and other deployable structures will be made by TokyoTech, WEL Research, and Sakase Ad-Tech and they will be delivered to our laboratory. We will carry them into the airplane and conduct the deployment experiment in micro-gravity environment.


Progress

The progress of the project is shown in the blog of ORIGAMI project.The following is the brief summary of the micro-gravity experiment by using an airplane conducted in January and February, 2016:

[Yamazaki, February 2017]

Objective

The objective of this experiment is to develp the design and verification method of advanced deployable space structures by fusion of experiment and numerical analysis.

The deployable space structure consisting of lightweight and highly storable members such as membranes, cables, and thin booms reduces the weight and the stowed volume much more than conventional space structures, so that it is expected to be applied to the large structures such as solar sail, laege antenna, and sun shield. However, it can be affected more easily than conventional structures by small disturbances such as gravity, aerodynamic force, and friction that are negligible in space, so that they say it is difficult to predict its behavior (equilibrium state and dynamics) under the space environment.

It is necessary for the practical use of such deployable space structures to clarify the mechanism of the influence of the disturbance such as gravity, aerodynamic drag, and friction on the behaviour of the structure, and also to control these disturbances if possible. Therefore, we defined the objective of the experiment as to expect the mechanism by investigating the effect of the gravity, aerodynamics drag, and the size of the structure, and to propose the design and verification method of such structures.

Especially, we focused on the establishment of the data collection method under micro-gravity environment, so we conducted various types of structures as follows:

  • Braid Coated Bi-Convex boom deployment system (Braid Coated Bi-Convex :BCON),
  • Membrane deployment system for nano-satellite OrigamiSat-1 (OrigamiSat Deployment Structure:ODS),
  • Extensible boom for photogrammetry of membrane of nano-satellite OrigamiSat-1 (OrigamiSat Deployment Boom:ODB),
  • Deployment system of Convex boom(Single Convex:SCON),
  • Deployment system of inflatable membrane structure (Combined Membrane:CM),
  • Spin deployment systemof membrane (Spin Deployment Membrane:SDM)

 

Summary of each deployable structure

[BCON : Deployment system of Braid Coated Bi-Convex boom]

We measured the deployment motion of the boom and membrane, and the behaviour of the comvex tape in the hub. We conducted the experiment of several parameters for the rotary damper of the hub, the folding pattern of the membrane, and the existence of the membrane. Then, we evaluated the effect of the friction under 1G environment by comparing with that under micro-gravity environment, and the constraint force for the extension of the boom induced by the deployment of the membrane. In the result, we detected the parameter that gives major effect on the success of the deployment.

Figure 1  BCON Deployable Structure

[ODS : Membrane deployment system of nano-satellite OrigamiSat-1]

We conducted the deployment experiment of the scale model of membrane deployment system for nano-satellite OrigamiSat-1. In this experiment, we did not use the gravity conpensation system that is necessary in 1G environment. We measured the deployment motion and the reaction force to the deployment system, which enable us to construct the high fidelity numerical model. We conducted various types of the system, i.e. the system with different types of the constraint of the center hub, that with/without membrane, that with sevaral kinds of booms, that with sevaral types of the connection between booms and membrane, and that with different size of membrane structure. In the result, we got the data necessary for the evaluation of the effect of the constraint, resistance force of the membrane, the material of the boom, the connection method of the boom, and the size effect as well as the effect of the gravity conpensation system.

[ODB : Extensibl boom for nano-satellite OrigamiSat-1]

We conducted the extension exmeriment and evaluated the effect of the disturbance in the extended state for the scale model of the extensible boom that will be used for the support of the camera for the photogrammetry of the deployment of the membrane mounted on the nano-satellite OrigamiSat-1. We got the data for the evaluation of the characteristics of the boom.

Figure 2  Deployable structure for OrigamiSat-1

[SCON : Deployment system using convex booms]

We conducted the deployment experiment of the SCON deployable structure. The content of the experiment is the same as that of the BCON: We measured the deployment motion of the boom and membrane, and the behaviour of the comvex tape in the hub. We conducted the experiment of several parameters for the folding pattern of the membrane, and the existence of the membrane. Then, we evaluated the effect of the friction under 1G environment by comparing with that under micro-gravity environment, and the constraint force for the extension of the boom induced by the deployment of the membrane. In the result, we detected the parameter that gives major effect on the success of the deployment.

Figure 3  SCON Deployable Structure

[CM : Deployment system of membrane combined with inflatable tubes]

We conducted the deployment experiment of the combined membrane structure under micro-gravity environment. We mwasured the motion of inflatable tubes and the membrane, pressure of the inflation gas during the deployment, and the vibration of the tube after the deployment. In the experiment, we used the several specimen, i.e. changed the length of the tube and membrane, and the gas pressure. In the result, we got the data necessary for the high fidelity numerical analysis model, and detected the parameter that gives major effect on the success of the deployment.

Figure 4  Combined Membrane Structure

[SDM : Spin deployment system of membrane]

We measured the deployment motion of the scale model of spin deployment system of membrane with low spin rate that cannot be achieved in 1G environment. We conducted the experiment for several cases, i.e. changed the size of the membrane, thickness of the membrane, number of fold lines, and spin rate. In the result, we got the data necessary for the construction of high fidelity numerical analysis mode and the similarity rule, and detected the parameters that gives major effect on the success of the deployment.

Figure 5  Spin Deployment Structure


Summary of experiment

You reported the status of the experiment at our laboratory weblog. You can see the shot movie on the experiment in the below:


College of Science and Technology, Nihon University
Department of Aerospace Engineering
Miyazaki and Yamazaki Laboratory
College of Science and Technology, Nihon University
7-24-1 Narashinodai, Funabashi, Chiba 274-8501, Japan
e-mail: asel (at) forth.aero.cst.nihon-u.ac.jp