Accession Number : ADA017182

Title :   A Non-Conservative Retrieval of a Tethered Passive Astronaut.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OHIO SCHOOL OF ENGINEERING

Personal Author(s) : Titmas,Gary William

Report Date : MAR 1975

Pagination or Media Count : 71

Abstract : A non-conservative (angular momentum is not conserved) procedure is developed to safely retrieve a tethered passive astronaut on an extravehicular assignment (EVA). The safe retrieval of a tethered astronaut by conservative procedures has been shown to be impossible unless the conditions upon initiation of retrieval are exceptional. Safe recovery is defined as a max rotation rate of 0.5 rad/sec, a max impact velocity of 5.0 ft/sec, and a max centripetal acceleration of 8.0 ft/sec squared. This last requirement is treated by limiting the tether tension to 100.0 lfb as the astronaut's mass is taken as 13.04 slugs. To ensure the max impact velocity is not exceeded, the astronaut is reeled in at a constant rate of 5.0 ft/sec. A safe recovery is achieved by insisting that the space vehicle 'track' the astronaut during the EVA. Then, when retrieval is initiated, a force is applied through the center of mass of the space vehicle to null the angular acceleration of the astronaut with respect to the space vehicle.

Descriptors :   *Astronauts, *Umbilical cords(Aerospace), Recovery, Extravehicular activity, Tethering, Tracking, Computer programs, Theses

Subject Categories : Astronautics

Distribution Statement : APPROVED FOR PUBLIC RELEASE