 James Joseph Sylvester developed his construction of Hadamard matrices in 1867, which actually predates Hadamard's work on Hadamard matrices.Hence the name "Hadamard code" is disputed and sometimes the code is called "Walsh code", honoring the American mathematician Joseph Leonard Walsh.An augmented Hadamard code was used during the 1971 Mariner 9 mission to correct for picture transmission errors.