The Jupiter project was to be a new high-end model of Digital Equipment Corporation (DEC)'s PDP-10 mainframe computers.
This project was cancelled in 1983, as the PDP-10 was increasingly eclipsed by the VAX supermini machines (descendants of the PDP-11).
DEC recognized then that the PDP-10 and VAX product lines were competing with each other and decided to concentrate its software development effort on the more profitable VAX.
The PDP-10 was finally dropped from DEC's line in 1983, following the failure of the Jupiter Project at DEC to build a viable new model.
[1] This computer hardware article is a stub.