Earth Departure Stage
The Earth Departure Stage (EDS ) was the sixth announced by the NASA Ares V rocket as part of the Constellation program. By setting the Constellation program, the construction of the Ares rocket was set. The EDS should provide the drive for future flights to the moon, to Mars and possibly other targets.
The EDS was developed by the Marshall Space Flight Center of NASA in Huntsville (Alabama ) and was essentially an enlarged Saturn upper stage (S- IVB ) with larger tanks. It would be a J- 2X main engine with a fuel from a liquid oxygen ( LOX) and liquid hydrogen (LH2 ) being driven. As the supreme Sufe the Ares V would have worn a Altair lunar lander, which would have been protected at the start of a payload fairing.
Unlike the Apollo moon missions, as the third stage (S - IVB ) of the Saturn V rocket then carried the Apollo spacecraft and the lunar module together in one Earth orbit and on the way to the moon, EDS would be with Altair first in a parking orbit flown around the Earth. Then the Orion spaceship with a crew of up to four were started on an Ares I into space, coupled with the waiting EDS to the lunar module. Then the J- 2X engine would have been fired a second time and had the Altair lunar lander, including Orion spacecraft accelerated to a path to the moon.