Space data systems are how spacecraft and the ground talk to each other — the quiet plumbing of radios, antennas, and packets behind every mission flying today.
What makes them fascinating isn't the engineering — it's the constraint underneath. A spacecraft is a computer you cannot touch, operating in an environment trying to kill it. Everything in this field follows from that.
So I wrote this primer the way I wish someone had explained it to me: follow one spacecraft from its first signal to a network spanning the solar system, each protocol appearing the moment it becomes necessary.
It's not a textbook — it's my attempt to make the field feel inevitable.
— Ravi Suhag