Earth Departure Stage
Encyclopedia
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
Earth Departure Stage (EDS) was a rocket stage
Multistage rocket
A multistage rocket is a rocket that usestwo or more stages, each of which contains its own engines and propellant. A tandem or serial stage is mounted on top of another stage; a parallel stage is attached alongside another stage. The result is effectively two or more rockets stacked on top of or...
which NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
planned to design at its Marshall Space Flight Center
Marshall Space Flight Center
The George C. Marshall Space Flight Center is the U.S. government's civilian rocketry and spacecraft propulsion research center. The largest center of NASA, MSFC's first mission was developing the Saturn launch vehicles for the Apollo moon program...
in Huntsville, Alabama
Huntsville, Alabama
Huntsville is a city located primarily in Madison County in the central part of the far northern region of the U.S. state of Alabama. Huntsville is the county seat of Madison County. The city extends west into neighboring Limestone County. Huntsville's population was 180,105 as of the 2010 Census....
as part of Project Constellation
Project Constellation
Constellation Program is a human spaceflight program within NASA, the space agency of the United States. The stated goals of the program were to gain significant experience in operating away from Earth's environment, develop technologies needed for opening the space frontier, and conduct...
. The EDS would be propelled by a single J-2X main engine fueled with liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
(LOX) and liquid hydrogen
Liquid hydrogen
Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be...
(LH2), and would fly in a manner similar to that of the S-IVB
S-IVB
The S-IVB was built by the Douglas Aircraft Company and served as the third stage on the Saturn V and second stage on the Saturn IB. It had one J-2 engine...
rocket stage used on the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...
rockets that propelled the three-man Apollo
Project Apollo
The Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...
missions to the Moon between 1968 and 1972.
Design
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
's External Tank
Space Shuttle external tank
A Space Shuttle External Tank is the component of the Space Shuttle launch vehicle that contains the liquid hydrogen fuel and liquid oxygen oxidizer. During lift-off and ascent it supplies the fuel and oxidizer under pressure to the three Space Shuttle Main Engines in the orbiter...
, the EDS would have used two J-2X engines, while the Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
core booster would have used five Space Shuttle Main Engine
Space Shuttle main engine
The RS-25, otherwise known as the Space Shuttle Main Engine , is a reusable liquid-fuel rocket engine built by Pratt & Whitney Rocketdyne for the Space Shuttle, running on liquid hydrogen and oxygen. Each Space Shuttle was propelled by three SSMEs mated to one powerhead...
s and two 5-segment Solid Rocket Boosters
Space Shuttle Solid Rocket Booster
The Space Shuttle Solid Rocket Boosters were the pair of large solid rockets used by the United States' NASA Space Shuttle during the first two minutes of powered flight. Together they provided about 83% of liftoff thrust for the Space Shuttle. They were located on either side of the rusty or...
during the first eight minutes of flight.
When the Ares V was then redesigned around the use of five (later six) RS-68B rocket engines currently used on the Delta IV EELV family, the EDS was then redesigned using only a single J-2X engine and a common bulkhead, thus in its current design, the EDS now resembles 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.
Mission
Launched on the Ares VAres V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
rocket, the EDS with its Altair payload does not become active until the six RS-68 engines cutoff and the Ares V core is jettisoned to burn up in Earth's atmosphere. Upon separation using the on-board staging and ullage motor
Ullage motor
Ullage motors are relatively small, independently-fueled rocket engines that may be fired to accelerate the rocket prior to main engine ignition, when the vehicle is in a zero-g situation....
s, the single J-2X engine then fires at full thrust to place itself and the Altair into a Low-Earth orbit until it is then retrieved, via a separate launch, by the Orion spacecraft
Orion (spacecraft)
Orion is a spacecraft designed by Lockheed Martin for NASA, the space agency of the United States. Orion development began in 2005 as part of the Constellation program, where Orion would fulfill the function of a Crew Exploration Vehicle....
and its four-person astronaut crew.
Once the Orion is docked with the Altair and its systems are checked out, the crew will jettison the "loiter skirt" and then fire the J-2X engine for a second time, this time at 80% rated thrust, for Trans Lunar Injection
Trans Lunar Injection
A Trans Lunar Injection is a propulsive maneuver used to set a spacecraft on a trajectory which will arrive at the Moon.Typical lunar transfer trajectories approximate Hohmann transfers, although low energy transfers have also been used in some cases, as with the Hiten probe...
(TLI). Unlike the S-IVB, which propelled the Apollo Spacecraft
Apollo spacecraft
The Apollo spacecraft was composed of five combined parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth...
and its three-man crew in a forward-facing motion, the EDS will fire its onboard rocket with the crew facing the EDS. This "eyeballs out" type of flying will be similar to the flight profile of the proposed, but never flown Manned Venus Flyby
Manned Venus Flyby
A manned Venus flyby was considered by NASA in the mid 1960s as part of the Apollo Applications Program, using hardware derived from the Apollo program...
, from the canceled Apollo Applications Program
Apollo Applications program
The Apollo Applications Program was established by NASA headquarters in 1968 to develop science-based manned space missions using surplus material from the Apollo program...
of the late 1960s.
When TLI is completed and the EDS is shutdown for the last time, it is jettisoned to fly into a heliocentric orbit
Heliocentric orbit
A heliocentric orbit is an orbit around the Sun. All planets, comets, and asteroids in our Solar System are in such orbits, as are many artificial probes and pieces of debris. The moons of planets in the Solar System, by contrast, are not in heliocentric orbits as they orbit their respective planet...
, or in a manner similar to that employed by NASA from Apollo 13
Apollo 13
Apollo 13 was the seventh manned mission in the American Apollo space program and the third intended to land on the Moon. The craft was launched on April 11, 1970, at 13:13 CST. The landing was aborted after an oxygen tank exploded two days later, crippling the service module upon which the Command...
to Apollo 17
Apollo 17
Apollo 17 was the eleventh and final manned mission in the American Apollo space program. Launched at 12:33 a.m. EST on December 7, 1972, with a three-member crew consisting of Commander Eugene Cernan, Command Module Pilot Ronald Evans, and Lunar Module Pilot Harrison Schmitt, Apollo 17 remains the...
, it may be deliberately crashed into the lunar surface to help scientists calibrate sensitive seismometers placed on the lunar surface by either astronauts on lunar sortie
Lunar sortie
A lunar sortie is a human spaceflight mission to the Moon. In contrast with lunar outpost missions, lunar sorties will be of relatively brief duration.- NASA sorties :...
flight or by unmanned robotic probes.
Other uses
While the EDS will primarily be used for Orion/Altair lunar sortieLunar sortie
A lunar sortie is a human spaceflight mission to the Moon. In contrast with lunar outpost missions, lunar sorties will be of relatively brief duration.- NASA sorties :...
, and later lunar outpost flights to the lunar polar regions, the EDS would also be used for the proposed Orion Asteroid Mission to a Near-Earth Asteroid, and possibly be used for the launching of the proposed 8 to 16-meter Advanced Technology Large-Aperture Space Telescope
Advanced Technology Large-Aperture Space Telescope
The Advanced Technology Large-Aperture Space Telescope is an 8 to 16.8-meter UV-optical-NIR space telescope proposed by Space Telescope Science Institute, the science operations center for the Hubble Space Telescope...
(AT-LAST) to the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
-Earth L2 Lagrange Point. The EDS itself, or a derivative of the EDS may also be used for the eventual mission to Mars after 2030.