dietz%usc-cse@USC-ECL@sri-unix (11/29/82)
Two corrections. First, it was STS-2 (not 5) that discovered the rivers, using the SIR-A synthetic aperture radar. Second, the rivers could hardly be used to irrigate crops, as they haven't carried any water for thousands of years. They are buried under meters of sand. The sand was very dry, so the microwaves from SIR-A could penetrate it down to the bedrock, uncovering the riverbeds.