TypeScript didn't exist when the decision on the language was made. And nobody will launch anything into space that didn't see a decade of testing and then it s

TypeScript didn't exist when the decision on the language was made. And nobody will launch anything into space that didn't see a decade of testing and then it still needs to be integrated into a craft that will launch 10 yrs in the future. They wanted a scripting language, likely to make updating stuff around the craft easier, it's high level control so low level languages don't make that much sense. You'll likely see Rust and other modern languages in about 15 years or so flying into space.