# 3U CubeSat components

as a project for school, we are designing a preliminary conceptual 3U CubeSat design. The mission is to launch in orbit at 1,000 km and Maintain orbit for 1 month. After orbit is maintained for 1 month, the CubeSat will reduce orbit by 100 km over the course of 1 month. After new orbit is reached it will maintain that orbit for 1 month, and repeat the process until it reaches earths atmosphere where it will then burn up.

Our structure consists of Power, Structure, Thermal, COMMS, ADACS, Orbital, and Payload. We have a target objective of designing this for \$25,000 with a max threshold of \$100,000. The mission will consist of measuring charged particles.

We have gathered all components for each subsystem, except payload and we are already at our objective price. We have done extensive amount of research for COTS components, and looking for guidance on which components you guys recommend to reduce our costs as much as possible.

What components do you guys recommend that are cheaper than what we’ve found? Our most expensive area is ADACS, where the computer, magnetometer, Nadir, sun sensor, is around \$15,000. Do you know a cheaper way to go about doing it. This CubeSat consist of Solar Sail for our propulsion. Please let me know what you recommend as far as components go for each subsystem, so I can look up pricing. Thank you for all your help. • Sounds like an exciting project! I think you may have run into a brick wall; if you want to have so many features and buy them from specialized "cubesat shops: you may not be able to fit them into your budget. It means you may have to make some yourself or use non-space qualified COTS (commercial off-the-shelf) parts instead. By the way there's also a policy in Stack Exchange against "What should I buy?" shopping questions. – uhoh Mar 2 at 19:52 • I didn’t know that, I apologize. Well in that case, how would I go about designing a sensor for measuring High Energy Charged particle density? Out of all the research we have done we have found similar missions but they don’t discuss how the detector/telescope were made. You don’t have to name specific components, but how would I go about finding how to design one, or if you have any suggestions on how to? Mar 3 at 1:08 • For the charged particles let's get your unnecessarily closed question reopened ASAP! – uhoh Mar 3 at 1:20 • \$15K seems both high and low. High for a cubesat, but low for a vehicle that will spend several months in the lower Van Allen belt. Have you thought of asking your computer science department to join in on the fun? Use a bunch of cheap single board computers and cheap sensors for redundancy. The computer science group can learn about synchronization amongst computers and about the Byzantine Generals Problem. Mar 3 at 14:03
• Your sun sensor and horizon sensor do not necessarily have to be parts that are explicitly built to do those jobs. Have your computer science department work with you to make cheap digital cameras do the job. Mar 3 at 14:06

Since this is a common question, I'll try taking a crack at it. As was mentioned in the comments, this is not the place for "what should I buy" questions. Therefore my answer may seem a bit non traditional. What I'm about to say regarding reducing costs holds true not just for CubeSats, but also for $100M satellites. 1. First and most important - Evaluate and revisit all your requirements. Do you really understand the requirements, and can you trace them to your mission objectives? Are some of your requirements really "desirements" that make the mission better, but are not needed? Some examples in your case: • You mention ACS is expensive. What drove you to select the current ACS? For instance, does the pointing need to be so good as to require star trackers or can you get away with magnetometers and sun sensors? • You start at 1000 km, which as someone pointed out, is a pretty heavy radiation environment. Can you start lower and switch to less radiation tolerant parts? 2. Make/Buy trades. You can always debate building your own component vs buying one. Invariably the initial trade for make may come out cheaper ("We can do that!"). However, when you buy, you are often paying for expertise, more thorough testing, and flight-proven heritage. On the other hand, there is a lot to be learned by designing and making your own component. 3. Take into account complete life cycle costs. You may save \$10k by buying a cheaper flight computer, but if the software library it comes with is poorly documented, or even worse, buggy, then you will quickly run through the equivalent of \\$10k in your labor and schedule delays.