New applications of space tethers (High-Voltage Tethered Satellite System project) are discussed in relation with ideal of an active experiment in the Earth's radiation belts. Two conducting strings are supposed to be tethered between the main satellite and two small subsatellites flying through the ERB. A large potential difference similar to 1MV is applied between the tethers by means of a generator carried on the main satellite. The tethers effectively scatter the high energy particles into loss cone of magnetic trap, providing a control of particle life time in ERB. The rigorous theory of the sheath layer formed by relatively cold plasma is developed, yielding the electric field profile,which is then used for the treatment of scattering problem. With the help of Fokker-Planck equation the average rate of particle losses, normalized per 1 km of the tether's length is found to be: (2.5 divided by 14) . 10(16) s(-1) km(-1) for electron belts and 1.8 . 10(14)divided by 2.5 . 10(20) s(-1) km(-1) for proton belts. New active experiments in space become possible under the joint realization of HVTSS and HAARP projects.