When the Ares V was then redesigned around the use of five (later six[1]) RS-68B rocket engines used on the Delta IV Heavy as of 2019, the EDS was then redesigned using only a single J-2X engine and a common bulkhead, thus in its final design, the EDS resembled an oversized S-IVB, but with the capability of on-site storage (using new propellant storage techniques along with a "loiter skirt" containing solar panels for electricity) for up to 4 days, something impossible with the old S-IVB.

This "eyeballs out" type of flying would be similar to the flight profile of the proposed, but never flown Manned Venus Flyby, from the cancelled Apollo Applications Program of the late 1960s.

[2] When the Ares program was cancelled in favor of the Space Launch System, the EDS was considered as a second stage for the Block 1B SLS.

[4] Technological development of the J-2X was expected to take considerably more time, so the EDS was dropped in favor of the Exploration Upper Stage, which will use the much lower-thrust but already-developed RL10.

According to NASA, the J-2X will be overpowered for the Artemis program; its development has been put on hold until stages capable of transferring heavy payloads to Mars are required (expected in the 2030s).