Note that they were using titanium, and while I'm not sure what the fuel cells were made of, until they heated up it leaked quite a bit. One of the first order

Note that they were using titanium, and while I'm not sure what the fuel cells were made of, until they heated up it leaked quite a bit. One of the first orders of business after takeoff was getting a refuel, which included changing the type of fuel, see e.g. http://iliketowastemytime.com/facts-you-didnt-know-about-sr71-blackbird http://iliketowastemytime.com/facts-you-didnt-know-about-sr7...