Sixteen small vibrating motors are embedded in the back connected to a control unit on the side of the vest.

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The control unit ends up in a lower orbit, but it can then use solar power and the electrodynamic properties of the tether to return to its original orbit.

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The problem came to light when a Propulsion Drive Electronics (PDE) control unit picked up a difference in pressures between the oxidiser and the fuel going through one of the ATV's four "propulsion chains".

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