Thursday, 16 January 2014

How do I start to build a PocketQube?

So, you think the idea of building your own Sputnik seems pretty cool. I don't know if it's a good pick-up line at parties, but as far as personal achievement goes, it's up there. But where to start?

Disclaimer: I'm not an expert, or even qualified to give financial advice...This post is just to give potential people or teams a place to start and spur imagination and further exploration.

Back to the story. If you've got to the point of thinking that you're capable of building a satellite, you probably got at least some knowledge about what's involved. Yes? No ? I'm not going to write this "Choose your own Adventure" style, so I'll start with some basics.

You've got as far as deciding on a form factor for the satellite. PocketQube. Now, what size PocketQube are you going to build? If you know anything about getting things into space, it's not exactly cheap, and the cost is based on mass. The bigger the chassis, the larger the mass. So a 1P PocketQube is the smallest in the range, and you can go up from there, generally in .5P increments, up to 2.5P. PocketQube Shop can provide a range of off-the-shelf hardware. Or you can build it from scratch like Wren . Depends on the skills you or your team possess. You just need to ensure it complies with the PocketQube Standards.

Next. Subsystems.

There's a few critical systems you'll need to have. While they can be separate, and often are in cubesats, they may need to be integrated for a PocketQube. But as far as design goes you'll need to think about the following:
Power ( Generation and storage)
Command and Data Handling ( CDH)
Attitude Determination and Control Subsystem ( ADCS)

Now you're going to have to "hit the books", both literally and metaphorically. Each subsystem can be considered a specialist area, and there are many books on each one. Pocketqube's haven't been around for a while, so there's nothing currently written that's specific to the platform.
At the cheaper end of the scale ( less than $8), there are general books such as "DIY Satellite Platforms" by Sandy Antunes. The other end of the scale has textbooks like the "Handbook of Satellite Applications" that costs $850.
Or you could use the internet. The Cubesat standard has gone through the same progression that the PocketQube standard will undoubtedly go through. There are presentations from Cubesat Developers Workshops  . There are peer-reviewed publications . There are hundreds of PhD Thesis that can be Googled.

At the end of the day, you'll need to apply what you learn and build your satellite. There's not yet a complete turnkey COTS solution for Pocketqubes, so you'll have to roll up your sleeves! You'll need to understand each of the subsystems and devise a way to integrate them all. You'll learn things like "Link Budget" and that Lithium Polymer batteries won't charge in temperatures below 0C, and many other intricacies of building a satellite.

Testing. Do what the $50Sat team did and breadboard your satellite. At early stages, you don't need to have the final circuit board designed. You don't need the space rated solar cells for testing your control and radio code. When you get close to finalising these things, make 1 or more engineering models so you can test mechanical systems like antenna deployment.

There's definitely alot to learn if you're an amateur like me, but it's achievable. The cost of the hardware isn't exorbitant, and you just need the dedication and enthusiasm ( ok, and aptitude) to build your own satellite.