Cooks and Kolchak's ambition....

So, apparently the mission Rock Hudson and Karl Kolchak go on is able to carry an astronaut whose primary job is to be the cook to the likes of Briggs (what was his specialty anyway?)?
And, Karl Kolchak's (Darren McGavin) main ambition is to leave the dreary, regimented astronaut corps so he can start up his own chain of Diners (just plain food, you know, hamburgers, french fries, hot dogs) and is so proud of that ambition that he boasts about it at parties.
Later on Mars he is seen all dressed up like some cowboy on acid, all excited to start cutting up the onions for the burgers - wow, too bad he had to have wasted all those years as a lowly astronaut!