The International Space Station uses the callsign IT1SS (India Tango One Sierra Sierra). This callsign does not exist and is not one of the callsigns used by the international space station; which are, in fact: Russian: RS0ISS, USA: NA1SS, European: DP0ISS, OR4ISS, IR0ISS. So when the spacewalking astronaut, Gio, uses NA1SS, he is in fact, using the US astronauts call sign, when he is an Italian.
Jake and the astronaut both come up with "1604" as the length of the isosceles triangle which enabled the main plot line to move forward. However the correct answer should be approximately 1624.