Download or read book Site Accessibility and Characteristic Velocity Requirements for Direct-descent Lunar Landings written by Vernon J. Weyers and published by . This book was released on 1961 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: A direct descent is one in which the main descent propulsion system burns continuously from lunar approach to touchdown. The characteristic velocity requirement for direct lunar descents is presented as a function of the landing site location relative to the normal impact point. Results are included for translunar trip times of 60, 75, and 90 hours, for specific impulses representative of both Earth storable and cryogenic propulsion systems, for landing sites located anywhere on the lunar surface, and for ignition thrust-to-Earth weight ratios between 0.12 and 10.0. The data presented are useful in determining approximate performance capability and in evaluating tradeoffs during preliminary mission planning studies.