Analysis of information sources in references of the Wikipedia article "Control moment gyroscope" in English language version.
Propellant Usage • Traditional Soyuz Undock: 10-40 kg • Soyuz undock on US Control: 0-1 kg • Savings per year (4 Soyuz/year): 40-160 kg
No more million-dollar maneuvers. When the space station must rotate for operations such as docking of resupply vehicles, it uses thrusters that run on propellant costing nearly $10,000 per pound. This demonstration successfully rotated the station 90 and 180 degrees without propellant, saving more than 1 million dollars worth of propellant on the 180-degree maneuver. The new technology uses gyroscopes, or spinning momentum-storage devices powered by solar energy, to maneuver along special attitude trajectories. It will substantially reduce propellant use and contamination of solar arrays and loads. With this technology, long-duration space exploration missions can carry less propellant and more provisions
Lost in all of this exchange of complaints is the fundamental engineering problem of what actually is forcing the Russian thrusters to fire during spacewalks. American and Russian space workers have strikingly incompatible theories about the causes. [...] Lost in all of this exchange of complaints is the fundamental engineering problem of what actually is forcing the Russian thrusters to fire during spacewalks. American experts believe that water vapor jetting from a cooling unit in the backpack of spacewalkers is strong enough to turn the entire two-hundred-ton space station out of alignment. This overloads the American stabilizing gyroscopes and triggers the firing of Russian rocket thrusters. The effect has been noticed on past station spacewalks that use the Russian space suits. For their part, Russian engineers believe a small air leak from their airlock hatch could be cause. Other Russian experts blame it all on a malfunction in the American gyroscopes (which Russians call "gyrodines"), with no Russian problem at all.
