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Space Science

Ask Slashdot: How Would You Build a Microsatellite? 117

Dishwasha writes "A fellow co-worker of mine turned me on to CubeSat; apparently there are commercial space companies that will launch CubeSat systems from their payload for a modest fee. Is anybody in the /. community involved in amateur microsatellite systems? How would I go about getting involved at an amateur level? Are there any amateur user groups and meetups I can join? I have limited background in all the prerequisites but am eager to learn even if it takes a lifetime. Any links to design and engineering of satellites would be appreciated."
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Ask Slashdot: How Would You Build a Microsatellite?

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  • by qubezz ( 520511 ) on Wednesday December 19, 2012 @07:26PM (#42343207)
    I would pay commercial space companies to launch my CubeSat systems for a modest fee. RTFA.
  • by frovingslosh ( 582462 ) on Wednesday December 19, 2012 @07:28PM (#42343223)
    You might want to get a ham radio license, and even if you don't, visit the website of Amsat (http://www.amsat.org), a worldwide group that has put many satellites in orbit. You are welcome to join even without an amateur radio license.
  • by eldavojohn ( 898314 ) * <eldavojohn@@@gmail...com> on Wednesday December 19, 2012 @07:30PM (#42343235) Journal
    Disclaimer: I have no personal experience doing this. I noticed on O'Reilly there is a cheap series of books [oreilly.com] by Sandy Antunes [wikipedia.org]. I think surviving orbit will be your biggest challenge [oreilly.com]? No clue on the quality of those books ...
  • by camperdave ( 969942 ) on Wednesday December 19, 2012 @07:45PM (#42343357) Journal
    The most important thing is to decide what you want your CubeSat to do. Are you out for a Sputnik style beacon that you can detect when it goes overhead? Are you going to be taking pictures of all the balloon cameras that didn't make it into space?

    Once you decide what you are going to do, then you can start in on the design. Cubesat.org [cubesat.org] has all sorts of design guidelines, etc.

    As for organizations, mailing lists, and the like, the external links on the Wikipedia page you linked into your article should provide an excellent starting point.
  • by __aaltlg1547 ( 2541114 ) on Wednesday December 19, 2012 @07:50PM (#42343415)

    Stanford and Cal Poly has been involved from early on and has a lot of experience with cubesat launches. UNM also has a program and I think UM and U of Utah Logan. Probably lots of others. Basically schools with a strong Aerospace program are likely to be involved and help with getting in contact with good people. You may, if you have interesting tech knowledge, be able to advise a group of students on a project they are already doing.

    Also the air force schools do projects (AFA and AFIT) but they might be harder to work with.

  • by PlusFiveTroll ( 754249 ) on Wednesday December 19, 2012 @07:56PM (#42343457) Homepage

    Anyone can build anything, the question is, will it work when it gets there.

    Space is a totally alien environment from habitable earth. It's like being in the desert Antarctic and the inside of a nuclear reactor at the same time. If you're in the sun it's very hot and out of the sun it is very cold. There no atmosphere and whatever particles are around can contain high energies. Many substances stable at atmospheric pressure become volatile. Special lubricants have to be used to avoid all kinds of issues with evaporation, freezing, or sticking. Solar flares can fry you.

    Any leaks or evaporation from the satellite can cause it to spin out of control. Any control system failure is fatal. You don't get to test the unit in zero gravity before hand. Your solar and power storage have to deal with all the above issues. Oh, if your components get hot, they have to radiate the heat away, no convection to do the work for you.

  • by Audrey23 ( 663718 ) on Wednesday December 19, 2012 @08:28PM (#42343659)
    You will find much information on AMSAT (http://www.amsat.org) , JAMSAT (http://www.jamsat.or.jp) or AMSAT-UK (http://www.uk.amsat.org) for some of the amateur organizations around the world, they have been around for decades and have a wealth of experience and can use any offered help! Also get your amateur radio license and then you can access the existing birds that are up there, ARRL (American Radio Relay League) or RSGB (Radio Society of Great Britain) or other organizations are a good place to start. I can't seem to get links to work on /. so will have to leave it up to you to google the above acronyms to find out more. I have built my share of down-converters and donated my share of money to get some of the satellites into orbit, it is extremely expensive to get something into orbit, not so hard building it in comparison, most of the expense is just getting it out of the gravity well and orbiting. In fact if you go to the UK AMSAT web site they have a bit on the latest cubesat on there now :)
  • by AikonMGB ( 1013995 ) on Wednesday December 19, 2012 @09:03PM (#42343861) Homepage

    A metal cube in low Earth orbit will equilibrate to about 25C if you cover the outside with solar cells and some reflective tape. The radiation environment isn't really all that bad below the Van Allen belts; use automotive grade parts and in general you'll be fine. No need to worry about lubricants because you shouldn't have any mechanical actuators (unless it's part of your payload or you really want to fly a reaction wheel). Good thermal ground planes in your boards and metal bosses tieing them to the structure will move heat away from components just fine. No need for a "point-or-die" solution, just put solar cells on all faces of your satellite; if you lose control authority (e.g. computer crash) you still generate enough keep-alive power. Gravity doesn't really have any impact unless your payload is a mechanical actuator, which again is not very common at the amateur cubesat scale. Leaks -- don't use pressurized gases or fluids; evaporation, just pick materials with < 1% total mass loss and less than 0.1% CVCM (i.e. Teflon insulation on wires instead of PVC).

    As it turns out, amateur space isn't all that hard to do.

  • by AikonMGB ( 1013995 ) on Wednesday December 19, 2012 @09:08PM (#42343889) Homepage

    Generally speaking, microsatellites are in the range of 10 kg to 100 kg. What you are talking about are cubesats, which are generally nanosatellites (1 kg to 10 kg) and picosatellites (< 1 kg). As others have said, the AMSAT programme is a great starting point; next August come out to the Cubesat workshop [cubesat.org] and, if interested, hang out for the USU Small Satellite Conference [smallsat.org]; lots of industry, academia, and government representation. We host a booth every year, as do most relevant players in North America.

  • by AikonMGB ( 1013995 ) on Wednesday December 19, 2012 @09:26PM (#42344009) Homepage

    Yeah, you can have omnidirectional antenna coverage for both uplink and downlink. Our S-band transmitter is capable of 1 Mbps omnidirectional downlink at 650 km. This is the preferred method if you can close your link and data budgets because it makes the system vastly simpler and inherently fail safe (if it crashes and you lose attitude control, you can still talk to it). A secondary directional downlink may be reasonable if you have very high data requirements (e.g. streaming video or ultra high definition imagery), but generally speaking you never want to be in the situation where you can't talk to the spacecraft if it can't point at you, even in big space.

  • by wakeboarder ( 2695839 ) on Thursday December 20, 2012 @01:03AM (#42345109)

    Having been on a team that has built and launched two cubesats, I consider myself somewhat of an expert in the area. I'll answer this question to the best of my knowledge, I've been to the cubesat conference for several years now (it's mostly academics but most of the launch companies are there.) The first couple of years as a student I would get all excited whenever companies like this would start up. I noticed quickly that the same company never came around to the conference more than a few years, why? Because they couldn't get the funding, a launch requires some where in the range of 10$ million. There are plenty of companies that start up and claim that they will launch a rocket with a 50-100 (or so cubesats) and that will cover there costs, the problem is they have to find that many people to fill the spots. No one has done that yet. Cubesats were designed as a containerized system to mitigate the testing and integration launch costs. Everything that goes to space has to be thoroughly tested, when you have to do this on a case by case basis, it takes a lot of time (=money). So if you already know your payload will fit in a 10cm x 10cm x 10cm (1U) and has a ~1kg weight then that saves a lot of testing. Another benefit of the container is NASA can slap them all over their rockets and launch 10's of them (currently) at a time. Since every rocket has tons of payload margin (you want to ensure your payload reaches space you size its mass several percent smaller than what the rocket can handle to ensure delivery) and some payloads are in the tons, throwing on a few cubsats won't really do a thing to your mass budget. Now NASA has a program for this: http://www.nasa.gov/mission_pages/smallsats/elana/index.html [nasa.gov] this has been successful. As far as launching your own, I wouldn't count on it in the near future. Launching a satellite is not trivial, you have to make sure its not going to break apart, or damage other payloads on the way out of its container. Look up ISBN: 047075012X . You have to make sure its not going to outgass because volatile compounds evaporate and can cause problems. You have to use materials that can withstand the rigors of space, atomic oxygen and radiation can be rough on most materials. Plus some materials like PVC will evaporate in a vacuum. Another problem is ensuring you have enough battery and solar power to support your payload. You have to make sure you payload will not shake apart on the way up (rockets are very very bumpy rides). The satellite should have an attributed and control system to make sure it can orient itself in the right direction (for your solar cells and radio). And last but not least is the radio and comm system. A ground station is needed and the appropriate radio frequencies used (if you want anything fast you have to get a license from the gov, this is very difficult). The satellite itself needs to have a good antenna (if you have any nulls in your antenna pattern then you won't be able to communicate with it when the null is pointed at you. Oh, and if you put a camera on it the NOAA has to know about it and approve of your data (really stupid, but that's the way the government is). Anyway I could go on for a long time... Building a satellite requires people from many different disciplines to pull it off. Unless you are going for insanely simple you would have to have a group of people to accomplish the task. If there is available access and launch costs come down I could see a few hobbyists groups pulling it off in 10 or so years if they can clear all of the governmental hoops. I won't believe any commercial venture claiming that they will launch cubesats (or tubesats http://interorbital.com/TubeSat_1.htm [interorbital.com]) until they actually do.

Long computations which yield zero are probably all for naught.