Nanotechnology and space By Ali Ghasemi

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1 In the name of god Nanotechnology and space By Ali Ghasemi Abstract: Nanotechnology is an ability to produce new materials and systems by working in molecular and atomic sales and utilizing the features which occare in these sales. This means that nanothechnology is anew viewpoint to different science rather than a new branch of science. Some of the scientists claim that Fymens speech about working in molecular scales in 1959 make the researchers to think deeply about nanotechnology. Nano structured materials have notable features which are caused from the size of particles which build them, they are produced in two main method, 1) Top-Down method 2) Down-Top method Nanotechnology may hold the key to making space flight more practical. Advancement in nanomaterials to make lightweight solar sails and also in nano powders to make engines with better propulsion systems and also in other fields like nano sensors, nano coaters, could significantly cut the costs as well as reducing the amount of rocket fuel, used. Also new materials along with nano sensors could improve the performance of spaceships and spacesuits. Keywords: - MEMS: (Micro Electro Mechanical Systems) Kind of systems with small size which have electric and mechanic part. - Hall- petch: is a method of strengthening materials by changing their average grain size. Introduction: Nanotechnology revolutionize the world' scientists claimed and people in close contest for participating in this new technology try to establish different sites, present relevant reports and introduce new products with ' nano ' prefix. Nanotechnology is an exciting area of scientific development which promises 'more to less'. It offers ways to create smaller, cheaper, lighter and faster devices that can do more and more and most clever than things, use fewer raw materials and consume less energy. This is why developed countries invest millions of dollars in this technology. Nanotechnology is the ability to work in molecular or atomic dimensions to produce new materials. This means that nanotechnology is a new viewpoint to different science rather than a new branch of science. Nanotechnology can play a variety of rules in aero space industry and space systems, including wiring. High- strength lightweight composite materials, thermal protection and cooling systems and electronics/ sensors. Familiarization with basis concepts of nanotechnology and creation a general view about the usage of this technology in aero space is the main purpose of this paper. Definition of nanotechnology:

2 Nanotechnology is nominated to the part of technology which in this part all kind of alloys, structures, tools and generally systems in atomic and molecular scales with nano metric dimensions can be designed and also can be built. The range of dimensions in nanotechnology is between 1 to 100 nanometer. This range include so many part of scientific areas like atomic physics, chemist so in order to clear the difference between nanotechnology and other scientific areas we assume that nanotech only includes the method of design and produce of nanometric materials in this range. Important nano materials feature: Generally the features of materials related to the atoms which build them and also the order of them. Moreover when the size of particles which anstruct a material than a specific size, the dimensions of particles will affect on its features. The features of nano materials are divided in six groups. 1) Mechanical features such as higher ductility, negative gradient in hall-petch diagram, 2) Thermal features: such as ability to control the rate of heat transmission, expansion coefficient, 3) Chemical features: such as increase in effective surface in chemical reactions. 4) Photonic features: such as materials with the ability to absord specific wave length. 5) Electronic features: such as materials with the ability to control the rate of electric transmission. 6) Magnetic features: such as materials with magneto- resistance. Method of producing nanomaterials: There are two main methods for producing these materials: 1) Top- Down method 2) Down- Top method Moreover, Self- Assembly is another method which is concluded in Down- Top method. 1) Top- Down method: It was introduced by Mr. Fymnman firstly. In this method, systems with bigger dimensions build smaller ones till the nanometric systems become appear. 2) Down- Top method: In this method nano materials are built from joining smaller particles like atoms together by self- assembly method. In this method chemical and biological reactions are used for self- assembly. History of nanotechnology: Use of nanotechnology by human has a long background. There are some documents about the blue color which has been used by Maya tribe which prove this claim. After those Romanics use these materials to build cups with live colors, they use gold as manner of powder.

3 One of the first scientific reports about nanotech was about producing the solution of gold in 1857 by Michael Faradey. After that the black carbon was used for painting and hardening tires. Catalysts with nano structure first have been used about seventy years ago. In the beginning of 1940,s decade the silica nanometric particles have been produced which was the best substitution for black carbon. In 1960 and 1970 decades metal nanometric powders for saving information on the strip have been produced. Some of the scientists claim that the biggest event in world of nanotech was the speech of Richard Feyman in U.S.A physics society conference in He presented his article which its name was:" There is a plenty of room at the bottom ". and speak about manipulating materials in atomic dimensions. He through computations represented that it is possible to save Britain dictionary on a top of needle. Space and nanotechnology, relevant fields. 1) Nano structured materials: One of the vital technologies for future missions which is studied in NASA especially, is the extensing of materials with low weight and appropriate strength which can persist in space. The usage of these types of materials in deployable systems, prepare very tiny spacecrafts for the missions which are impossible without them. Adjustable thermal features, self- repairable materials will make a big change in future of space missions. 2) Nano composite materials: The substitution of metal- metal, ceramic and plastic Nano composites in the body of cars and aerial vehicles like rockets will decrease the rate of burning fuels, increase lifetime, increase range and also make the vehicles unseen from the radars. In the futures nano carbon tubes with ٨٣ percent tower weight from steal and ٥٠ times more stronger than steal will use in a wide variety of fields. 3) Nano coating materials: Mono molecules coats have many important usages in aero space industries. These thin layers can be used on the metallic or plastic surface to increase frictional resistance incredibly. Two usages of this technology are mentioned as followed: A) Use of nano diamond as a coat of combustor to increase strength and heat transmission. B) Use of Carbide- Tungsten as a thermal shield on the top of rockets with a resistance equals to Uranium- Tantalum. 4) Nano powder materials: One of the usages of this powder is in optimization of consumption of fuels. For example Alumina go on a reaction with Oxygen and release energy for about four times more than Hydrogen. But because of the coolness in effective surface in a manner of powder the reaction is not intensitive enough.

4 But the new type of Alumina nano powders burn completely and release their energy intensively. 5) Nano electronic: Technologies for processing, sensoring and managing the data for space systems are important. The high pressure for extending electronic of space systems is caused. From: 1) Making the spacecraft independent from controlling stations. 2) Need of collecting big series of data in future missions. 3) The ability of self reparing and managing. Fatal errors. The limitations which exist in micro electronic in Aero space usages like low- consumption elements, resistance to radio beams reflections make them in appropriate. So the researchers try to solve these problems with nanotechnology. Applications under Development Researchers are looking into the following applications of nanotechnology in space: - Using carbon nanotubes to make the cable needed for the space elevator, a system which could significantly reduce the cost of sending material into orbit. - Employing materials made from carbon nanotubes to reduce the weight of spaceships while retaining or even increasing the structural strength. - Producing thrusters for space craft that MEMS device to accelerate nanoparticles. This should reduce the weight and complexity of thruster systems. One cost- saving feature of this type of thrusters is their ability to draw on more or less of the MEMS devices depending upon the size and thrust requirement of the spacecraft, rather than designing and building different engines for different size spacecraft. - Using carbon nanotubes to build lightweight solar sails that use pressure of light from the sun reflecting on the solar cell to people a spacecraft. This solves the problem of having to lift enough fuel into orbit to power spacecraft during interplantery missions. - Working with nanosensors to monitor the performance of lift support systems. - Deploying a network of nanosensors to search large areas of planets such as Mars for traces of water or other chemicals. - Including layers of bio- nano robots in spacesuits. The outer layer of bio- nano robots would respond to damages to the spacesuit, for example to seal up punctures. An inner layer of bio- nano robots could respond if the astronaut was in trouble, for example by providing drugs in a medical emergency. Conclusion: As mentioned before, Nanotechnology has so many usages in different fields. Generally investing in nanotech in different fields is based on three important purposes: 1) To minimize systems, 2) To produce new materials with new features,

5 3) To increase efficiency of systems, Developing space missions and aerospace technologies which have the same purposes, use nanotech in a very good manner and so many applications have been developed under nano tech to improve aerospace industry. References: 1) spotlight/ spotid Php 2) 3) ~ skb/ nanomaterials. Html 4) nano 5) An introduction to nanotechnology, A.Shokohfar& K.Momeni, dec ) Nanotechnology and its usages in aerospace industry, Sh.Zandie, Oct 2003