SPACECRAFT ARE UNIQUE ENGINEERING PROJECTS, WITH CONSTRAINTS AND REQUIREMENTS NOT found in earth-bound artifacts. They must be able to endure harsh temperature extremes, the hard vacuum of space, and intense radiation, and still be lightweight enough for a rocket to loft them into space and send them to their destination. A spacecraft is an exercise in applied minimalism: just enough to do the job and no more. Everything that goes into the design is examined in terms of necessity, weight, and cost, and everything is tested, and then tested again, before launch day, including the embedded computer system that is the "brains" of the spacecraft and the software that runs on it. This chapter is an overview of how the image processing software on the Phoenix lander acquired and stored image data, processed the data, and finally sent the images back to Earth.