Moon Base: A Serious Game for Education

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Abstract—To increase the interest of young people in the technological and scientific aspects of space research, the Eu- ropean Space Education Resources Office (ESERO) has decided to develop a set of games with space themes. Our group was selected to design and implement a game in virtual reality. In this paper, we describe the main design principles, interaction and navigation techniques, technological details, and user experience of the final game titled Moon Base. Index Terms—educational game, virtual reality, space explo- ration

I.INTRODUCTION Enjoyable, funny and exciting activities significantly help users to understand and to remember a subject of interest. That is why usage of games in education is widely accepted as a great and efficient extension to traditional education processes. This approach is even accelerated in the last years when powerful smartphones and attractive devices like VR headsets become widely available for a young population. An extensive survey of the serious games in education can be found in [1]. The authors show an increasing number of Fig. 1. Moon Base: Spaceship take-off preparation. suitable games for educational purposes and their indisputably positive effect on learning. On the other hand, they also mention various issues with the integration of games into have led to the development of educational game Moon Base schools. We share their observation dealing with a certain which is described in the following text. skepticism among students, low acceptance by some teachers, and technological obstacles, however, we believe that all these II.RELATED WORK issues change in time and that most problems will soon Usefulness of applying games to increase the interest of disappear quite naturally with the increasing impact of the students and to fulfill their hunger for knowledge has been information society. shown in several papers. It covers a wide range of target users Having all these facts above in mind, the European Space 1 starting at primary school [2] up to university classes [4]. Education Resources Office (ESERO) tried to arouse the Kleinhans at al. [2] describe their complex approach con- interest of students at secondary and high schools towards sisting of classroom game (targeted to primary schools) called research in space by developing a virtual reality (VR) game. Expedition Mundus, bringing pupils to a science museum, Such a game could increase the number of highly motivated and experimental work on sandbox scale models. Although students both at universities of technology and natural sci- no computers support was included and the game was based ences. As we register a shift of students’ interest from these on paper materials including maps, cards, text with anecdotes areas of education to social and management fields in last and scientific facts, the authors were able to cover the Earth, years, the activity of ESERO is welcome especially at our the Moon, and the Mars. university with a long tradition of education in technology More technically oriented education game is described in areas. [3]. The authors created a computer game based on a real The ESERO intention and support together with our experi- Apollo lunar exploration mission. The game develops mul- ence in computer graphics, user interfaces, and virtual reality tidisciplinary activities in three phases - planning routes on 1ESERO is a project of the European Space Agency (ESA) targeted to the lunar surface, loading science equipment, driving a rover. education. Game components build on scientific data from NASA, both Fig. 2. Moon Base: the main menu offers a selection from five voyages of exploration. for digital elevation model (terrain) and 3D virtual lunar rover rocket types in the hangar (Ariane 5R, Ariane 5C, and Ariane vehicle and its controls. A usability study was performed on 5P), which are dismantled into several pieces, see Fig. 3. The a group of 30 participants between the ages of 19 and 38. goal in this scene is to try to assemble an Ariane 5 rocket and The game was positively accepted and marked as a game inform users about tow strength, weight, and amount of fuel with a power to engage youth and young adults in Science, the rocket needs to reach the cosmic space. Technology, Engineering and Mathematics (STEM) learning. This scene requires the handling of rocket parts and an easy We also appreciate the Kerbal Space Program game pre- to understand system for joining these parts together. It is also sented by Ranalli and Ritzko [4]. Students in the first year of necessary to solve the movement over a large area in all three their Engineering Design study build a rocket that could fly axes (i.e., even vertical movement). from the Earth to the Moon and return safely. The model of the Each rocket part is extended during the interaction with spaceship was motivated by Apollo 8. However, students are color balls informing the user about proper parts placing required to compute their rocket parameters and to simulate and parts compatibility. The parts are automatically snapped various flight phases like take-off, orbital trajectory movement, together if corresponding balls are close. Moreover, each and landing. As the students have to concentrate on correct rocket part is annotated by factual information. The user can computations and simulations, the game itself is not very naturally walk on the platform (it is bounded by the railing) but complicated, but students were still enthusiastic about using a for traveling on large distance or in the vertical direction, she game in education. has to use the platform control panel to transport, see Fig. 3 While the previously mentioned serious games have limited and Fig. 6. scopes, e.g., the Moon exploration in [3] or rocket construction in [4], we aimed to offer a complex view on space research Scene 2: Take-off possibilities and activities. To achieve this goal, we have The second scene retakes place at the Guyana Space Center. intentionally suppressed a priori technical knowledge required In this scenario, the user will become familiar with the launch for the game, but extended a game scope to five very different process of the Ariane 5P rocket, which begins by bringing areas to engage various users/players. the missile from the ’final assembly building’ to the launch pad, see Fig. 1. Subsequently, first phases rocket engines are III.GAME DESIGNAND PRINCIPLES launched, and the rocket takes-off the earth. The first phase The main task was to present a variety of activities that engines are discarded after reaching the space, and second are connected with space research. Each part of the game phase engines ignition occurs. should motivate players to become interested in a different The entire rocket launch process is prepared as a cinematic discipline(s). Since we know neither the users’ preferences animation; it can be freely played, skipped, played backward nor their educational background, we have decided to offer and repeated to get the eventuality to investigate the launch them a choice from five game activities/scenes (short stories process deeply. For this purpose, there are also several viewing and corresponding tasks). A selection from these choices is positions in the scene, from an outer view around launchpad, shown in Fig. 2. attached to the rocket, or from Earth orbit. The key to this Game scenes are fully independent, no achievements and scene is a media player (Fig. 1) that influence the flow of no knowledge from one scene are necessary to enter and play time in the scene in different ways. another scene. The content and the most significant features of every scene are as follows: Scene 3: Operations in Microgravity The third scene takes place in one module of the ISS Scene 1: Spaceship Construction (International Space Station) where the user can experiment The first scene takes place in a space rocket hangar (for- with barycentric balls, i.e., to study how the center of mass mally Launcher Integration Building - BIL) in Guyana Space (barycenter) is determined by geometrical properties of a center in French Guiana. There are three different Ariane bodies-system and not by the mass of individual bodies like Fig. 3. Moon Base: Construction of different Ariane rockets in a virtual hangar. A user can see information about rocket parts during an interaction. There are visible helpers for correct parts placement (colored balls). A platform control panel is visible in front of the user. it is on the Earth. This scene fully reflect ESA educational Scene 5: Moon Research Laboratory material Barycentric balls [9]. The fifth scene takes place in the laboratory inside the Moon The user will be able to assemble a system of objects Base. Rock soil samples will be tested for soil grain and from balls and sticks. The physics behavior of the body calcium content. The soil grain test is carried out using a sieve system is simulated concerning microgravity, and it orbits set of different fineness, in this case, two sieves. around a common center of mass. There are four drawers The testing procedure is as follows: a sample of the lunar with an endless count of sticks and three different balls (pool rock is weighed, the sample is then divided into three different ball, tennis ball and bowling ball). Users can freely connect coarse fractions using sieves (coarse, medium coarse and fine). balls and sticks together and explore the physical behavior of The weight ratio of the fraction to be sampled and the whole complex systems. sample determines the weight fraction of this fraction. The The navigation in the scene is specially designed to remind calcium test is carried out using a solution of vinegar. If a a movement in the state of weightlessness. The user grabs rock sample contains calcium, then in combination with the ISS module walls with hands; she can attract to them and is vinegar there is a reaction that occurs with rumbling. For the oriented by the direction determined from hand position and coarser sifting fraction, it is possible to see the rock-cut under wall normal. the microscope; the task will be to find a sample with a suitable microscopic structure. There are three containers in this scene, each contains Scene 4: Moon Surface Exploration another sample of lunar rocks (collected in Scene 4). Each container firmly determines the properties of the sample, The fourth scene takes place on the surface of the Moon i.e., the weight of the individual fractions, and whether the where the European Space Agency is planning to build a lunar sample contains calcium. The samples can be removed and base [10]. The aim in this scene is to collect samples of lunar subjected to testing. Different fractions are separated from rocks, which will then be used for various geological tests in the sample using sieves, thus generates five options: coarse a laboratory (Scene 5). The sampling of rocks will be carried fraction, medium fraction, fine fraction, a mixture of coarse out using the remote-controlled moon carriage. and medium fractions and a mix of medium and fine fractions. Since the moon carriage is remotely controlled, we need Also, there is a weight on which the samples and sieved to create a clear remote control in this scene. It will enable fractions can be weighed. In addition to the pots, a sample the user to navigate the vehicle to the sampling zones without of the vinegar is placed nearby. When the sample is put in the changing the location herself. The user will also be able to vinegar beaker and is immersed by the fluid, the visual effect track what the vehicle is currently doing by using the display (smoke) reveals which indicates whether the sample contains on the remote control, see Fig. 4. calcium or not. The last part of this scene is a microscope, Fig. 4. Moon Base: Moon rover is driven using virtual touchpad.

Fig. 5. Moon Base: The laboratory is equipped with various instruments including virtual computer, scales, sieves and microscope. Textual information is in Czech language as the first version of the game is targeted to Czech schools. Fig. 8. Moon Base: With Google Cardboard, rocket parts in Scene 1 or lunar samples in Scene 5 can be moved closer and further either by using a specific tool for each direction (see Fig. 9, buttons 4 and 8) or using a universal tool Fig. 6. Moon Base: Transportation platform in Scene 1 allows the user and a head inclination up to 30 degrees (5 in the same picture). movement over a large area in all three axes using the control panel in the top-left corner. which shows the rock cut for the coarsest faction. Interaction patterns and techniques The user interaction for generic VR systems can be gener- alized into high-level interaction concepts called patterns and techniques, see [11] for overview of commonly used. While the pattern represents a generic classification of interactions (i.e., walking pattern), the techniques are concrete pattern realization, often device dependent (like real walking, steady walking, walking with game-pad, etc.). We will describe individual implemented interaction tech- niques, in relation to interaction concepts described earlier in Fig. 9. Moon Base: Toolbox for Google Cardboard v2 controll. this section, and VR devices possibilities. We are designing the game for three different types of virtual reality devices as will be discussed in the next section. viewpoint direction is often realized by direct mapping It is an immersive headset with full head tracking and hand- of device sensors to orientation change (IMU on headsets motion controllers (like HTC VIVE), immersive headset with or mouse position change for PC variant). The change of positional and/or orientation tracking with limited user input avatar positions is commonly done by walking patterns or possibilities (Google Cardboard, Google Daydream, and other automated patterns (like teleportation or passive vehicles). phone-based VR devices), and for PC with a monoscopic or We have implemented a special variant of a walking stereoscopic screen. pattern on larger distances for HTC vive, where the user moves hands controllers forward and backward like during a real walk, see Fig. 7. In PC variant the walking is realized like in FPS-like (First Person Shooter) game, ie. WASD keys on a keyboard. On Google Cardboard we replace the walking by teleportation (i.e., automated pattern). Walking is enabled in Scenes 4 and 5. Avatar positional change in Scene 1 is realized by passive vehicle. We create a platform with a control panel (Fig. 6), and the user changes his position by manipulating buttons on the control panel. This platform can move in Fig. 7. Moon Base: Walking in Scene 4 and 5 is realized by hands waving all three axes. from front to back around the user body. A steering of movement is determined by the torso reference frame forward direction. Selection pattern Selection in our game is realized with Pointing pattern, i.e., the user can target interactive ob- Viewpoint control pattern Viewpoint changes can be sepa- jects even on larger distance than is his motor space by rated into two components. The continuous change of something like a laser pointer. We have two techniques for pointing pattern; one is designed for HTC vive, it is a hand pointing where the laser pointer is projected from the end of a hand controller. The other is targeted for Google Cardboard and PC variant. It is Gaze pointing. In this case, the laser pointer is projected from the cyclopean eye (center space between the user’s eyes) through the center of the user’s view, where is a visible pointer. The selection action is performed after trigger press on hand controllers, a button press on a cardboard box, or mouse button press in PC variant. Manipulation pattern Interactive objects can be operated using a 3D tool manipulation pattern. We mostly change Fig. 10. Abstract interaction layer design. objects positions by ”levitation” tool with the possibility to move objects also closer and further from the user. Thanks to limited operability of Google Cardboard v2, we make special toolbox palette with concrete tools, goal at each scene was accomplished by all users with all VR see Fig. 9. In this VR variant, rocket parts in Scene 1 game variants. The main goal of tests was verification of UI or lunar samples in Scene 5 can be moved closer and intuitiveness on each device. further either by using a specific tool for each direction The target group of testing users was primary and secondary (see Fig. 9, buttons 4 and 8) or using a universal tool school students, i.e., people aged 8 to 20 years, see Fig. 11. and a head inclination up to 30 degrees (button 5 in We have eight participants. Each participant followed a fixed Fig. 9). The head inclination is depicted in Fig. 8. In scenario that should correspond to the real use of the game. other VR variants, these tools are mapped on buttons of The questionnaire form was filled after tasks accomplishment. interaction devices (hand controllers touchpad and mouse From the responses given by the participants to the question- with keyboard). Rocket parts in Scene 1 and stick and naire, all participants were satisfied with the game. Throughout balls in Scene 3 are extended with Jigs for easier placing testing, it was not found that some of the game’s components, of objects together, objects snap together if corresponding such as user interface elements or scene navigation, caused Jigs are close enough. nausea. Also, during the testing of the game, no error was IV. TECHNICAL ASPECTSAND USER EXPERIENCE detected that would make it impossible to complete the level or cause the fall of the application. An Error associated with the We aimed to enable this game to be playable at most user interface was detected in the 2nd and 4th scene in Google schools as possible. For this, we decide to make it as much Carboard variant - the UI for gaze pointing was to close to VR-platform independent, as is possible. The leading target the user and cause discomfort for the user. We summarized platform of our project is VR system HTC vive. Moreover, the positives and negatives that the participants mentioned in we implemented an interface for Google cardboard (and the questionnaire in the following text. other phone-based VR devices) and also PC variant with a monoscopic or stereoscopic view (Side-by-Side format). The main advantage of our approach is that the scene and game logic are the same for all platforms, and interaction interface solves mapping between game and HW-device. Specified user interaction interface was designed for each platform. While fully immersive headsets benefit from hand- motion controllers, the minimalistic cardboard variant can complete all tasks with just one button. The PC variant uses classic game interface with mouse and keyboard. See abstract interaction overview in Fig. 10. Our game was implemented in Unity, with OpenVR [5] support. Thanks to it, it can run on most immersive devices on the market (the HTC-VIVE devices [7] and also Windows Mixed Reality immersive devices [8] through the interface application [6]). Application testing All VR-device variants of the final game were tested with the target group. We altered the order of device variants to eliminate the influence of the order effect. Each individual Fig. 11. Moon Base: Girl assembling Arian5C rocket in Scene 1. Positives found during testing: The tasks, in reality, are rocket design, plastic water powered • The ability to interact with a large number of objects, rocket launch, barycentric balls, soil samples collection, and even those that are not needed to complete a task. collected samples analysis. The project day is now in the • Good first experience with virtual reality. process of accreditation by the Ministry of Education in the • Nice graphics. Czech Republic. Up to now, the project day was accomplished • Amusement, thoughtfulness and enthusiasm. by approx 150 students, but we are not able to say, how many • Natural navigation after the scene. times was also used VR part of tasks. • Elegant zooming and zooming out for Google Card- board v2. V. CONCLUSION • Positive evaluation of diegetic user interfaces. We have developed an educational VR game that has the Negatives detected during testing: potential to motivate students towards space exploration and research. Five separate game phases enable students to find • In the view of Google Cardboard v2, the user interface topics that are near to their previous interest or knowledge. appears in the second scene too close. Gifted users can even discover new research areas. The game • In the view of Google Cardboard v2, it was tedious to runs on several platforms which should make its practical look to the left so that they could control a moon rover usage and acceptance in school environments easier. in the fourth scene. The game is currently tested by teachers in selected sec- • Google Cardboard v2 overlaps the delta muscle with long ondary schools. In case that ESERO will recognize and gaming, forcing users to hold the device at eye level, appreciate the impact of the game on the target group, we which was not pleasant for a participant. will prepare a second edition of the Moon Base game upon • Lower frame rate in Google Cardboard v2. feedback from teachers and students. The game is not publicly available at this moment, so we provide an in-game video from a PC variant [12] (it is anonymous upload for review process). There are short sequences of all implemented interaction techniques from all levels.

ACKNOWLEDGMENT This work has been (partially) supported by [INTENTION- ALLY REMOVED FOR THE REVIEW PROCESS].

REFERENCES

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