TARS is well known as an anagram of STAR.
KIPP is named for physicist Kip Thorne.
I humbly submit that CASE is not something to do with "space"--if you take the spare p from KIPP etc etc, which seems to be the going theory.
It seems obvious that TARS is sort of Cooper's older brother.
While CASE is more like his son.
His adult son is played by CASEy Affleck. Whose character is even more laconic.