The first generation rower, known as the MK-1 device, makes use of a magnetic eddy current braking mechanism to vary the workload. A solid copper flywheel rotates between the legs of a forked armature with fixed magnets attached to each leg. A simple sliding lever moves the armature to control how much of the surface of the flywheel is covered by the magnets (and thus the resistive force). A chain and sprocket with a freewheeling clutch couples the flywheel to the rope spool, and a power spring provides the recoil force. A tiny DC generator coupled to a voltmeter gauge graduated in arbitrary units provides a relative indication of flywheel speed. The combination of workload setting, flywheel speed, and rowing cadence can be used to compare relative workloads preflight and in flight; however, such comparisons are largely subjective unless sophisticated means such as monitoring oxygen consumption (VO2 peak) are employed. The inability to precisely quantify workload is a major limitation of the MK-1 rower.
For launch and landing, the rower is stowed in a middeck locker. For use, it attaches to the seat studs on the Orbiter middeck floor. No seat is required for rowing in zero gravity; the crew member merely restrains his/her feet on the foot plates, grasps the handles, and rows with a conventional motion.
+ Version Used During Space Shuttle Missions
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