3U CubeSat components

Question

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.

Answer 1

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.
4. Consider descoping. Nobody ever wants to descope their mission, yet it is the easiest way to save money. I once worked with a PI on a proposal to NASA. The particular opportunity was cost-capped, and we were above the cost cap. I kept the telling the PI we needed to descope, to which he replied "My science is too important to reduce it in scope!". I couldn't help myself - my retort was "your science is so important it will stay on the ground because nobody can afford it." Reducing the scope of your mission by 20% may be enough to bring you within budget - and you still get 80% accomplished.