The continued development of Large Scale Integration (LSI) presages the advent of a fourth generation of computers, and is causing an upheaval at all levels of computer technology-both technical and managerial. Today's computers use integrated circuit components containing at most ten gates per component; however, LSI is introducing hundreds of gates per component and will eventually evolve into thousands of gates per component. To the aerospace planner, this technological breakthrough of LSI means tremendous reductions in cost, size, weight, and power consumption of logic components, together with increased speed and reliability. However, for the aerospace planner to successfully implement aerospace computers with LSI, the computer designers and managers must reorient their methodology and goals. A multitude of new design and cost considerations must be carefully scrutinized, and out of this must come the new techniques that will permit effective incorporation of LSI in aerospace computers. Higher speed, a smaller system, greater reliability, and lower cost stem from the physical structure (more gates per component with no increase in component size) of the LSI component. These inherent features of LSI, together with multiprocessor system organization, point to future aerospace computers with capabilities equal to today's best ground base systems.