DIY Satellite Platforms Sandy Antunes Editor Brian Jepson Copyright © 2012 Sandy Antunes O’Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (http://my.safaribooksonline.com). For more information, contact our corporate/institutional sales department: (800) 998-9938 or [email protected]. Nutshell Handbook, the Nutshell Handbook logo, and the O’Reilly logo are registered trademarks of O’Reilly Media, Inc. DIY Satellite Platforms and related trade dress are trademarks of O’Reilly Media, Inc. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O’Reilly Media, Inc., was aware of a trademark claim, the designations have been printed in caps or initial caps. Important Message to Our Readers: The technologies discussed in this publication, the limitations on these technologies that technology and content owners seek to impose, and the laws actually limiting the use of these technologies are constantly changing. Thus, some of the projects described in this publication may not work, may cause unintended harm to systems on which they are used, or may not be consistent with current laws or applicable user agreements. Your safety is your own responsibility, including proper use of equipment and safety gear, and determining whether you have adequate skill and experience. Electricity and other resources used for these projects are dangerous unless used properly and with adequate precautions, including safety gear. These projects are not intended for use by children. While every precaution has been taken in the preparation of this book, O’Reilly Media, Inc., and the authors assume no responsibility for errors or omissions. Use of the instructions and suggestions in DIY Satellite Platforms is at your own risk. O’Reilly Media, Inc., and the authors disclaim all responsibility for any resulting damage, injury, or expense. It is your responsibility to make sure that your activities comply with applicable laws, including copyright. Make Preface Can any hobbyist build a satellite? Our DIY guide steps you through designing and building a base picosatellite platform tough enough to withstand launch and survive in orbit. If you have basic maker skills, you can build a space-ready solar-powered computer-controlled assembly suitable for attaching instruments and rocketing into space. Our fundamental premise is that anyone can build a satellite. In Chapter 1, we cover things you can do in space, science and engineering concepts, art/science hybrids, AMSATs, and the potential for advanced concepts such as constellations of satellites. Invent the future! Chapter 2 discusses the basics of electronics, parts, PCB fabrication, and dealing with suppliers, and has some notes on learning reflow soldering. Chapter 3 then looks at the primary picosatellite chassis that you will use. Choose CubeSats or TubeSats, and you’ll find a variety of rigid frame designs, all with the purpose of giving you an instrument bay for your mad experiment. Chapter 4 discusses satellite power budgets and the limits on solar and battery power, while Chapter 5 provides a quick overview of flyable Arduino and BasicX- 24 onboard processors. To get it up there, you’ll need a rocket (Chapter 6), and you’ll need to plan then execute your entire build—hopefully aided by the milestone checklists in Chapter 7. By the end of this book, you should have a strong grounding in the requirements for building a picosatellite that will launch into space. We also recommend the other books in this series: our design, testing and integration book Surviving Orbit the DIY Way, designing a mission goal using the power of science with DIY Instruments for Amateur Space, and getting your data back to ground with DIY Data Communications for Amateur Spacecraft. In the meantime, I have picosatellites to build! (See Figure 1.) Figure 1. A TubeSat-style picosatellite being built Conventions Used in This Book The following typographical conventions are used in this book: Italic Indicates new terms, URLs, email addresses, filenames, and file extensions. Constant width Used for program listings, as well as within paragraphs to refer to program elements such as variable or function names, databases, data types, environment variables, statements, and keywords. Constant width bold Shows commands or other text that should be typed literally by the user. Constant width italic Shows text that should be replaced with user-supplied values or by values determined by context. TIP This icon signifies a tip, suggestion, or general note. CAUTION This icon indicates a warning or caution. Using Code Examples This book is here to help you get your job done. In general, you may use the code in this book in your programs and documentation. You do not need to contact us for permission unless you’re reproducing a significant portion of the code. For example, writing a program that uses several chunks of code from this book does not require permission. Selling or distributing a CD-ROM of examples from O’Reilly books does require permission. Answering a question by citing this book and quoting example code does not require permission. Incorporating a significant amount of example code from this book into your product’s documentation does require permission. We appreciate, but do not require, attribution. 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Find us on Facebook: http://facebook.com/oreilly Follow us on Twitter: http://twitter.com/oreillymedia Watch us on YouTube: http://www.youtube.com/oreillymedia Chapter 1. Overview All I ask is a successful launch, a clean radio signal, and a life just long enough to achieve that goal. So you’re debating launching your own picosatellite? If high-altitude balloons just aren’t high altitude enough, if you feel frustrated by the pace of space development, or if you just really, really like rockets and hardware, I think launching your own satellite is an excellent decision. This book will help you turn that decision into a plan, and turn that plan into finished hardware. But first, what do you want your satellite to do? What Is a Picosatellite? Picosatellites, by definition, are extremely small, lightweight satellites. The progenitor of the pico class is the CubeSat, an open source architecture that lets you pack anything you want into the 10cm × 10cm × 10cm cube. The CubeSat is a satellite as cute as a pumpkin. Forbes reported on one vendor, Pumpkin Inc., that supplies premade CubeSats. CubeSat itself is a specification, not a piece of off-the-shelf hardware, so Pumpkin decided to prebuild kits and sell them. If you have your own rocket to launch your CubeSat on, for $7,500 they’ll sell you a CubeSat kit. This neatly parallels InterOrbital Systems’ TubeSat. InterOrbital Systems (IOS) has the edge in price/performance, as they throw the launch in for the same cost. But it looks like neither IOS nor Pumpkin provide premades, just kits. So there’s still hobbyist work involved, but kits remove the need for engineering and just leave the fun part of assembly and integration. Figure 1-1. Two variants of a picosatellite, with quarters shown for scale TubeSats and CubeSats are slightly different, of course, and I am insanely pleased that both are advancing the idea of platform kits. This is a great step in the commodification of space research. Even if the mini CubeSat looks eerily similar to a Hellraiser Lemarchand box. (See Figure 1-1.) If you build a CubeSat, securing a rocket to launch it on is not difficult, merely expensive. A typical CubeSat launch cost is estimated at $40,000. There are several commercial providers promising future CubeSat rockets, assuming they complete development. Various NASA and International Space Station projects accept some proposals using the CubeSat architecture. There are more companies entering the private launch business each year, so prospects for getting a launch are becoming more robust. The TubeSat architecture from InterOrbital Systems is an alternative schema. Currently only supported by InterOrbital, it is very cost-effective. You get the schematics, main hardware components, and a launch on their still-in-development