Earth Departure Stage

The Earth Departure Stage (EDS) was the name given to the proposed second stage of the Block 2 Space Launch System. The EDS was intended to boost the rocket's payload into a parking orbit around the Earth and from there send the payload out of low Earth orbit to its destination in a manner similar to that of the S-IVB rocket stage used on the Saturn V rockets that propelled the Apollo spacecraft to the Moon. Its development was initially put on hold until stages capable for Mars are required. It was eventually cancelled in favor of Exploration Upper Stage.