When developing the Claymore 6P Pocketqube deployer on a budget I have had to make some decisions such as whether to make everything for scratch or to buy consumable of the shelf (COTS) components. I am sure people, SME, universities who are developing cubesats and pocketqubes face the same challenges. This is why I want to raise some things you should consider before deciding to build or buy.
How long you have till launch or the length of time you have in a project is something that needs to be considered.
Developing and qualifying a new pocketqube system can take a lot of time and this needs to be considered if you are under a tight schedule. Fault finding and identifying the root causes can be a time consuming process. However one thing I have done in the past is take off the shelf components and modified them for my needs. This helped speed up my development. If you pick parts that you know will work then that will help eliminate possible causes to a failed test which will also help reduce downtime.
Have you had previous experience in developing a similar system? Have you got the skills to be able to develop the subsystem or can you get help from a contractor,mentor or be able to join a training course?
If you do something for the 1st time (especially developing the various subsystems) it can be a daunting (but fun) task and you will likely make mistakes. However adequate training and support will help you avoid a lot of these mistakes.
However building your own system will enhance your capabilities. You can use COTS components to learn how to design and build your custom parts.
Is there an off the shelf solution available and can you acquire it on time?
If there is a system available and you can afford it you should consider the lead times as there is no point ordering that EPS system if it will arrive in 4 months time and you need to integrate your pocketqube to my 6P POD (hint hint) in 3 months.
If there is no solution that meets your requirements or none available then you have no choice but to build one yourself.
It doesn’t take long to find out that space qualified parts are expensive for example the HDRM I want to use for my deployer won’t be cheap.
If you are running a company or paying a team you need to understand that wages is an expense that is always overlooked when developing an in house system. Trying to build a custom solution on cheap parts or poor equipment is a false economy because you will more likely have to redo the design and it might take longer than it should be.
Also the complexity of the subsystem or part has to be considered. If it’s a simple mechanical system like a hinge yeah go ahead but if it’s an ADCS system or something just as complex you got to make sure you have the budget and time to develop and qualify it.
This can lead to a custom ADCS system being more expensive than a COTS ADCS. Also you have to make sure you have budgeted for rework, redesign and figuring out why your design failed as a new design built from scratch is more likely to fail in the 1st, 2nd and even 3rd attempts. For example if it takes you 4 months to build and test your custom system while paying an engineer at €2000 per month then you include machining costs, material, tooling, testing and equipment you could be looking at double or treble the price (unless you can get freebies) than the off the shelf system.
If you have the budget to develop a system that meets your needs then batter in. Plus once you crack it you could sell the system to new customers.
Building in house will enhance your knowledge of your system and as you gain more experience,knowledge and skills. This will allow you to build more advanced and reliable satellites at a faster rate. In addition it’s a great feeling when you bring a sketch to fully working solution.
When you are building a pocketqube or cubesat for the first time you should look into buying COTS for critical systems to help de-risk the development as there are less unknowns to deal with when testing your system. Once you have a space qualified system you could look into making your satellites from fully bespoke parts.