Jet A is jet fuel : the stuff that modern jet airplanes burn in their engines. Jet A specification fuel has been used in the United States since the 1950s. In the rest of the world Jet A-1 is used. Wikipedia says the primary difference is the freezing point : Jet A’s is −40 °C (−40 °F), Jet A-1’s is −47 °C (−53 °F). There is also Jet B which is a fuel in the naphtha-kerosene region, a blend of 30% kerosene and 70% gasoline, with a freezing point of −60 °C (−76 °F). It is for use in very cold temperatures (those expeditions to Antarctica?).
Anyway : my project team compadres and I were very happy to go home after a long week of reviews that were well received. A project such as ours at this stage is at an inflection point : the team has to report back to the sponsors and show what has been designed, and what the system will cost to construct. And they might just say : Whoa! That’s too much, we cannot let you go forward. But we are OK and should get the green light to go ahead.