It is well-known that TCP does not perform well in modern satellite-based communications due to the channel's very large bandwidth-delay product. The conventional solution is to make use of TCP's Large Window Scale (LWS) extension as defined in RFC1323 to increase TCP's windows size. However this can only be done if either the operating system or the application can be modified to explicitly make use of TCP's LWS extension during connection setup. This work proposes a novel TCP-SuperCharger (TCP-SC) to enable TCP to fully utilize the underlying network bandwidth without modification to the applications or the operating system. TCP-SC is implemented as a gateway along the path between the sender and the receiver. By estimating the receiver's processing capacity, TCP-SC allows the sender to transmit more data than the amount of receiver buffer available. As modern computers are very fast compared to network speed, this prevents the receiver's buffer limit from restricting the throughput achievable by TCP. Experimental results show that TCP-SC can enable existing TCP with default buffer size (64 KB) to achieve 98% link utilization over a satellite link such as the WINDS communications satellite with 1,000 ms RTT and 24 Mbps bandwidth.