Space Systems Lab
University of Maryland
Development of a Ratchetless Wrench for Extravehicular Activity
The idea for a "ratchetless" wrench came about because of an invention by NASA/Goddard Space Flight
Center (GSFC) engineer John Vranish. He was looking for an
alternative to the two-dimensional (2-D) sprags that were being considered for use in space. His
idea was to groove the races and round the edges of the sprags, creating a three-dimensional (3-D)
sprag. John took his sketches to GSFC Aerospace Engineering Techician Mike
Wade who developed the idea to replace the traditional ratchet with 3-D sprags. The
Space Systems Laboratory (SSL) is extending this to
extravehicular activity (EVA) tools for the astronauts.
Follow the links below to learn more or feel free to contact the lead engineer for the EVA tools
Since 22 November 1998, you are visitor number
Click on the image above for statistics on this page.
Please e-mail me at
have any comments or questions.
Back to Top