Construction of the SPS primary structure by another method

The construction of the solar power satellite (SPS) primary structure using aluminum foam is discussed. The aluminum is salvaged from expended external tanks. The advantages of this construction system are: (1) saving in launch costs; (2) faster construction rates; (3) possible lower cost structures; (4) promotes containerless processing in orbit; (5) uses almost any space debris; and (6) frees the shuttle cargo bay for other uses.