The on-board computers are the brain of a space shuttle. They control the space shuttle during take-off and landing and process the measuring signals of all sensors. Without them, a shuttle is not manoeuvrable. That's why they have to be extremely durable and insensitive. Your computing power is a joke compared to today's PCs or laptops. The 32-kilogram blocks have a storage capacity of 1 megabyte and a computing speed of 1.4 megahertz. In total there are five of these computers on board, one always serving as a reserve. The first computer generation, which flew until 1991, had only 416 kilobytes of memory and 450 kilohertz clock rate.