Tcl is used on the International Space Station to control or provide a programmatic interface to experiments, as part of an experiment platform.

Here's the reference: [http://www.linuxjournal.com/article/7190] in which we read:

    In an early stage of the Declic development, the French company EREMS, responsible for the PDHS development, 
    came up with the idea to use Tcl for the interface. Scientists now are given a complete programming language 
    to formulate the experiment. They can execute commands, store values from read commands in variables and 
    make decisions using the Tcl language for configuring the next executed command.

... good decision EREMS!

[RS]: As the article is dated August 2004, I'm not sure whether Tcl is still "out there"... :^) But in an international environment, [msgcat] could be helpful: "Юстон, у наш проблема"