Water-Landing Characteristics of a Reentry Vehicle

Abstract

Experimental and theoretical investigations have been made to determine the water-landing characteristics of a conical-shaped reentry capsule having a segment of a sphere as the bottom. For the experimental portion of the investigation, a 1/12-scale model capsule and a full-scale capsule were tested for nominal flight paths of 65 deg and 90 deg (vertical), a range of contact attitudes from -30 to 30 deg, and a full-scale vertical velocity of 30 feet per second at contact. Accelerations were measured by accelerometers installed at the centers of gravity of the model and full-scale capsules. For the model test the accelerations were measured along the X-axis (roll) and Z-axis (yaw) and for the full-scale test they were measured along the X-axis (roll), Y-axis (pitch), and Z-axis (yaw). Motions and displacements of the capsules that occurred after contact were determined from high-speed motion pictures. The theoretical investigation was conducted to determine the accelerations that might occur along the X-axis when the capsule contacted the water from a 90 deg flight path at a 0 deg attitude. Assuming a rigid body, computations were made from equations obtained by utilizing the principle of the conservation of momentum. The agreement among data obtained from the model test, the full-scale test, and the theory was very good. The accelerations along the X-axis, for a vertical flight path and 0 deg attitude, were in the order of 40g. For a 63 deg flight path and 0 deg attitude, the accelerations along the X-axis were in the order of 50g. Changes in contact attitude, in either the positive or negative direction from 0 deg attitude, considerably reduced the magnitude of the accelerations measured along the X-axis. Accelerations measured along the Y- and Z-axes were relatively small at all test conditions.

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Document Details

Document Type
Technical Report
Publication Date
Jun 01, 1959
Accession Number
AD0217731

Entities

People

  • John R. Mcgehee
  • Melvin E. Hathaway
  • Victor Jr. Vaughan

Organizations

  • National Aeronautics and Space Administration

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Accelerometers
  • Aeronautics
  • Agreements
  • Bodies
  • Cameras
  • Catapults
  • Center Of Gravity
  • Displacement
  • Experimental Data
  • Flight
  • Flight Paths
  • Frequency
  • Model Tests
  • Momentum
  • Motion Pictures
  • Photographs
  • Resonant Frequency

Readers

  • Control Systems Engineering.
  • Fluid Dynamics.
  • Thermal Physics or Thermal Science.

Technology Areas

  • Space
  • Space - Hall-Effect Thruster
  • Space - Spacecraft Maneuvers