This volume provides an immediate reference to aerospace-related events of 1970, enabling all of us to broaden or to refresh our crowded memories. As part of NASA% chronology series it is intended to help historians and other analysts in preserving historical accuracy and precisian. Perhaps the Apollo 13 problems that resulted in using the lunar lander Aquarius as a "lifeboat" will be the most readily recalled of the 1970 events. Yet, as this volume clearly indicates, there were many significant milestones in space and aeronautics. The lunar samples returned by Apollo 11 and 12 were intensively studied in the United States and 16 other countries; the last two Apollo missions scheduled were canceled; the feasibility of reusable space shuttles as a means of reducing the cost and expanding the versatility of space operations was examined in greater detail; the Skylab program to evaluate man's adaptation to the space environment proceeded toward its launchings in early 1973. Dividends continued to be returned from our scientific satellites already in orbit: Pioneer VI completed six orbits of the sun, providing data on solar weather on the far side of the sun; Oao II began transmitting ultraviolet spectral data on some 25 000 stars; Ogo III, IV, V, and VI made sky surveys which could correlate geophysical data from other satellites, sounding rockets, and ground-based instruments. Among the 38 new payloads launched by the United States were the first prototype satellite for an operational weather system, ITOS, and three Intelsat communications satellites. Japan and China both launched their first satellites during 1970. In aeronautics, research and development on the supercritical wing culminated in the first flight tests. And the X-24 "lifting body" made its first flight early in the year and moved into supersonic flight in October. Other kinds of events are also included in this chronology. Dr. Cyril A. Ponnamperuma of the Ames Research Center reported the first positive identification of amino acids of extraterrestrial origins, found in the meteorite that fell near Murchison, Australia, in 1969. Numerous entries evidence increasing international cooperation in and mutual benefits from space activities. The overall space program was being evaluated during all of 1970-at perhaps the very peak of our technological and scientific achievements in exploration, in basic science, and in application to earth-bound needs. Questions of the basic value of and the need for space activities in relation to needs for solutions of problems on earth were being explored in all sectors of our national life. The space frontier has been crossed and men, their thoughts and their machines, are no longer bound to our home planet Earth. The accessibility of space will have a place in man's life and thinking for all his future. Even against a backdrop of the broad range of earth-bound problems-poverty, pollution, world peace, and disruptive changes besetting most social institutions-man's new perspective on his place in a dynamic universe is a basic challenge. We appear to have been in an escalating scientific and technological revolution during the 20th century, its intellectual stimulus and constructive values perhaps best symbolized by the intense space venture of the past decade. The space program as a human enterprise, gaining new knowledge and skills and applying them to practical purpose, seems a symbol much needed in a world beset by doubts and fears and frustrations and with many difficult problems yet to solve.