An optimized higher-order polarization weight (HPW) incremental selective decoding and forwarding (ISDF) scheme is proposed for cooperative transmissions in satellite sensor networks (SSNs). First, an HPW method is designed with subchannel power allocation in encoding to enhance the antiinterference. Second, a cooperative decision in the destination is used to avoid error propagation for better outage probability (OP) and bit error rate (BER) performance. It switches between direct and cooperative transmissions alternatively by channel state information (CSI). Finally, the HPW coding information, cyclic redundancy codes (CRCs), and four special frame structures of polar subcodes are jointly fast successive cancellation list (FSCL) decoded to improve efficiency and BER performance. Finally, we apply the optimized polarization encoding and decoding to the relay system to form a new ISDF relay system for better coding efficiency, BER, and OP performance. Simulation results show that the proposed scheme obtains approximately 0.8 and 1 dB performance gains at OP of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${{10}^{-{2}}}$ </tex-math></inline-formula> and BER of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${{10}^{-{6}}}$ </tex-math></inline-formula> , respectively, when compared with those of the current ISDF scheme. Therefore, the cooperative scheme possesses efficient decoding and cooperation, which endows it a promising candidate relay scheme in SSNs.