Accession Number:

AD0269413

Title:

STABILITY OF CUSHIONED LUNAR LANDING

Descriptive Note:

Corporate Author:

LOCKHEED MISSILES AND SPACE CO SUNNYVALE CALIF

Personal Author(s):

Report Date:

1961-09-01

Pagination or Media Count:

1.0

Abstract:

Stability against overturning is analyzed for a landing vehicle having a crushable pad fixed to its base as the landing device. The pad material is assumed ideally rigid-plastic and its uncrushed shape is that of a prism with annular cross section. The analysis is confined to planar motion of landings made on a sloping surface. Boundaries defining the regions of initial translatory velocities that result in stable landings are given for a class of examples of practical interest in which the vehicle is horizontal and nonrotating at initial contact. Several sets of vehicle and surface parameters are studied, centered about a vehicle with satisfactory characteristics for a soft lunar landing on a 15-degree slope. It is found that due to an initial angle between the pad and landing surface, a strip of instability tends to appear centered about a critical initial velocity normal to the surface. This situation is aggravated by increasing either the slope, the vehicle mass radius of gyration, the center-of-gravity height, or the pad-crushing stress. Drop tests and the numerical results of this study indicate that, even for realistic crushable materials, an analysis based on rigid-plastic material behavior givs a good indication of stability characteristics. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE