Mass (CBE + Cont.): 162.5 kg; Payload mass: 22.5 kg Design: Single string, redundancy through multiple elements 7.1 m diameter He filled superpressure balloon Teflon coated for sulfuric acid resistance Vectran fabric plus Mylar film construction; metalized for low solar heating Power: lithium-thionyl chloride (Li-SOCl2) primary batteries (10.5 kWh, 22 kg) Telecom: S-band to Orbiter (backup to carrier flyby s/c); (plus short carrier signal to Earth for Doppler and VLBI data) Functions: 30 days science operation at 55.5 km float altitude,