Extended Lunar Outpost Radiation Shielding Colorado School of Mines Team Lunar Knights Trevor Morris John Luke Richards Henry Swider Aaron Totsch Scott Wiedemann Design Advisor: Prof. Nathalie Van Tyne April 7, 2008 Abstract: The cosmic radiation on the moon poses a real danger to astronauts and equipment on the lunar surface. The moon is an unknown unique world that can provide information about the formation of the earth, and can provide a gateway to the rest of the solar system. Without a shielding mechanism to block the hazardous radiation present on the lunar surface however, extended manned stays on the moon are not possible. We will be able to construct a permanent radiation shield by utilizing the plentiful titanium dioxide (TiO 2) deposits embedded in the volcanic glass at the Aristarchus Plateau. A layer of a titanium dioxide mixture surrounding the exterior of an outpost will significantly reduce the cosmic radiation. We hope that our research and designs will contribute to the continued human advancement and exploration into space. Introduction In order to cover a broader scope of the issues associated with the Radiation Shielding Project, our team has developed five unique subsystems, as shown in Figure 1-A. The subsystems are as follows: adverse effects of radiation on humans, material properties of titanium, lunar architectural design using titanium, geologic significance of the Aristarchus Plateau as a lunar outpost location, and the extraction and refining processes for lunar titanium. Each team member has researched and expanded upon one of the subsystems individually. • John Luke Richards has researched the geologic significance of the Aristarchus Plateau as a lunar outpost location. An extended stay on the moon would be monumental for humanity, but would be made much more useful to science in a lunar location with geologic significance. • Trevor Morris has looked into the dangers of radiation to humans. It is critical to know how much radiation is safe for humans in order to protect against it. With a better understanding of radiation and its dangers, the rest of the project has a much more specific goal. • Aaron Totsch has examined the material properties of titanium. If titanium is to be used as the primary component in the radiation shielding, we must know how well it will be able to block the radiation and how strong and durable it will be as a shield on the lunar surface. • Henry Swider has researched processes for extraction and refining of lunar titanium. In order for titanium to be used as a radiation shield, it must first be obtained from the lunar surface and then processed into a usable form. • Scott Wiedemann has worked on lunar architectural design. In order for the titanium to work effectively as a shield, the lunar architecture must be designed to maximize the titanium’s radiation dampening properties. 1 1.1 Geologic Significance of the Aristarchus Plateau 1.11 Introduction The purpose of this subsystem is to explain the geological significance of going to the Aristarchus Plateau for research of the Extended Stay Lunar Outpost Architecture project for the RASC-AL program. The subsystem will cover in depth why the Aristarchus Plateau, shown in Figure 1.1-A, would be an optimal choice for building a lunar outpost. NASA has plans to reach the lunar surface in the next 25 years in order to further study the surface of the moon and to start building a lunar outpost. The Extended Stay Lunar Outpost Architecture that our team is researching is based on the principles of mining the lunar surface for titanium dioxide (TiO 2) for possible use in building one of these outposts. This molecule is found inside red and orange glasses formed by lava flows on the moon. These lava flows harden into glass and have been shown to hold plentiful amounts of this TiO 2, a lot of which is contained around the Aristarchus crater. At the present time, radiation is a big problem on the lunar surface. Although the effects of radiation aren’t entirely known, it is confirmed that prolonged exposure to cosmic radiation is extremely dangerous to a human being, and thus our team is researching and designing ways to prevent any detrimental effects of the radiation. This subsystem focuses mainly on the Aristarchus crater, and what geological significance it holds for building a lunar outpost. Aristarchus has much titanium, and is also close to many geological landmarks that could be extremely useful for studying. This subsystem will help identify why it is important that we consider Aristarchus as a valid outpost point for future lunar outposts. 1.12 Lunar Resource Deposits 1.121 Lunar Titanium The lunar surface has many different molecules contained within it. This is due to cosmic radiation as well as lava flows and other geological events. One of the most important substances needed for our project design is the titanium dioxide found in the volcanic glass beads around the Aristarchus crater. The Aristarchus crater in particular has surprisingly high concentrations of ilmenite, a material rich in concentrations of TiO 2 as well as iron oxide (FeO) [1.1-1]. These deposits were found using the Hubble telescope with a very specific wavelength [1.1-2]. This wavelength is mainly ultraviolet, and is then converted into visible light to differentiate between the different compositions of the surface. As seen in Figure 1.1-B, the magenta colored areas are the places containing the ilmenite deposits. These deposits are extremely prominent in Schroter’s Valley, an area close by to the northwest. Recent studies have shown that low lying basaltic soil, such as the soil surrounding the crater, has (on average) 6% to 8% TiO 2 by weight [1.1-3]. This TiO 2 will be used as our defense against the cosmic radiation, and will hopefully be implemented in our architecture and design. 1.122 Lunar Oxygen Another important resource available for use is oxygen. Luckily, the ilmenite described above is also rich with oxygen, making it a very useful material. The oxygen is extremely important, because it can be used for breathing within a lunar module, for rocket fuel, and for any other materials requiring oxygen [1.1-2]. 1.123 Lunar Iron Again, the ilmenite is also very rich with FeO [1.1-1], which would be extremely useful in making metals of different alloys. Once we are on the moon, it may be necessary for humans to build new structures using different materials. Considering iron is used in abundance on our planet, it is safe to assume that it will be much needed on the lunar surface as well. 1.13 Close Geological Landmarks 1.131 Aristarchus Crater The Aristarchus crater is a very important geological site, for the impact that created it excavated basalt underneath the regolith [1.1-4]. This can aid geologists in dating the layers of the moon. In addition, the Aristarchus crater has extremely bright rays, which can be seen at extreme distances. It is unknown why 2 these rays are so intensely bright, so it would be in our best interest to study them. It is probably due to the crater’s age, but it is still an interesting site to examine. 1.132 Schroter’s Valley As mentioned before, Schroter’s Valley is an interesting place to be explored. In Figure 1.1-C, it is the area contained within the rille to the right of the crater. It can be seen in full in Figure 1.1-D. It is high in ilmenite, and has much of the underlying soil within it. Because the Aristarchus impact ejected so much deep soil, much of it came down into this area, making it a very valuable area of study. In this area, geologists can study materials that can help date certain aspects of the lunar crust. 1.133 Gruithuisen Domes Shown in Figure 1.1-E, these domes are located to the northeast of Aristarchus, and have an unknown composition. Strong evidence (such as silicic materials) leads scientists to believe the domes to be of volcanic origin [1.1-4]. A simple robotic mission launched from the outpost at Aristarchus would give us a great deal of information regarding these mysterious domes. 1.134 Lichtenberg Crater The Lichtenberg crater is located to the northwest of the Aristarchus crater. The Lichtenberg crater, shown in Figure 1.1-F, is another interesting geological site. It is believed to be of the Erastothenian age, and it is high in concentrations of FeO, TiO 2, and what is believed to be the youngest basalts on the moon [1.1-5]. This specific crater exposed pre-mare crust, a valuable specimen for geologists. This particular crater is also very young, even though its rays suggest otherwise [1.1-5]. Although the rays appear dark, usually indicating an old age, it was later found that the Lichtenberg crater’s rays reflect their composition rather than age [1.1-5]. 1.2 Lunar Radiation Levels and Human Radiation Susceptibility 1.21 Introduction The purpose of this subsystem is to explain current knowledge on types of lunar radiation, lunar radiation levels, and the effects that radiation has on human tissues. We will be utilizing the titanium deposits on the moon’s surface to create permanent radiation barriers from the dangerous cosmic radiation for the future lunar outpost. The design must protect astronauts and equipment for extended stays on the lunar surface. The radiation shield will be inexpensive, easily constructed, very effective, long lasting, and will provide opportunities for important geological research. This subsystem covers a critical part of the Extended Lunar Outpost Radiation Shielding project for the NASA sponsored RASC-AL program.