It's interesting to compare the waist tether (http://www.collectspace.com/images/news-020615h-lg.jpg http://www.collectspace.com/images/news-020615h-lg.jpg) fro

It's interesting to compare the waist tether (http://www.collectspace.com/images/news-020615h-lg.jpg http://www.collectspace.com/images/news-020615h-lg.jpg) from this article with locking carabiners used by rock climbers (http://www.rei.com/product/722360/black-diamond-rocklock-twistlock-carabiner http://www.rei.com/product/722360/black-diamond-rocklock-twi..., http://www.rei.com/product/722353/black-diamond-rocklock-screwgate-carabiner http://www.rei.com/product/722353/black-diamond-rocklock-scr...). I wonder what the design requirements were -- it seems surprising to me that the only locking part of the waist tether is a button. It seems like that button could get accidentally hit, causing the tether to unlock and become unsafe; that is, unless the button has a spring forcing it to the "lock" position. Interestingly, there is a new carabiner on the market whose locking mechanism is more like a button (http://www.rei.com/product/840193/black-diamond-magnetron-rocklock-locking-carabiner http://www.rei.com/product/840193/black-diamond-magnetron-ro...): the difference being that the mechanism must be activated from both sides (via pinching the purple parts in the image), and has magnets forcing the carabiner into the "locked" state when not being held unlocked. Also interesting is that the waist tether is adjustable. That could be a point of failure -- imagine floating off the end of your tether. Although I can't tell whether the waist tether is designed to attach astronauts to the spaceship, or just tools to astronauts. Howstuffworks.com implies it attaches astronauts to the spaceship (http://science.howstuffworks.com/spacewalk4.htm http://science.howstuffworks.com/spacewalk4.htm), but brighthub.com implies it's for tools (http://www.brighthub.com/science/space/articles/126178.aspx http://www.brighthub.com/science/space/articles/126178.aspx).