The Constellation hardware involves technology that was developed through the Space Shuttle program, although the Orion spacecraft also uses many of the design features from the Apollo program. The Orion spacecraft, which replaces the Space Shuttle spacecraft, is the compartment that will contain men and women as they voyage to the Moon (we have not had an astronaut place a footstep on the Moon since Apollo 17 astronauts Eugene Cernan and Ron Evans walked on the Moon in December 1972) and other distant places.

The Orion spacecraft consists of the Orion Crew and Service Modules (CSM)—or the Crew Module (CM) and the Service Module (SM). Thus, the CSM contains a conical-shaped crew module (CM) (which is shaped similar to the Apollo Command Module and holds four to six astronauts) and a cylindrical-shaped service module (SM) (which holds supplies).

Probably the most distinct feature of the Orion spacecraft is the way the CM returns to Earth. Instead of an ocean recovery as with the Apollo missions, the CM will land on solid ground with the use of parachutes and airbags (like the way that the Russians have been landing for decades). It would most likely land at White Sands Missile Range (New Mexico) or Edwards Air Force Base (California). Most of the CM will be constructed of a lightweight aluminum/lithium (Al-Li) alloy and covered with Nomex (a registered DuPont brand that is an aromatic polyamide material—what is considered an aromatic nylon and looks similar to a felt blanket).

The Orion SM, which is located behind the CM, will also be constructed of Al-Li alloy and use deployable solar panels instead of fuel cells and liquid hydrogen tanks for electricity. The Orion spacecraft will use solid hypergolic fuel for propulsion; that is, rocket propellants that spontaneously ignite when combined. This propulsion is similar to what is used with the solid rocket boosters (SRBs) that are used to help lift the Shuttle off the ground.

The Orion spacecraft will be launched from the Kennedy Space Center using a new Ares I rocket. The entire entity is called the Orion/Ares I launch stack. Its first stage (closest to the ground at lift-off) will look very similar to one of the Space Shuttle’s solid rocket boosters (SRBs) and its second stage (which is located between the first stage and the SM) will function like a small version of the Shuttle's external tank (ET).

The first stage consists of one modified SRB with five segments instead of four. When all of its fuel has been expended, it will be cast off, but recovered and used again like with the Shuttle program. The second stage will be fueled with liquid oxygen (LOX) and liquid hydrogen (LH2) and powered with an advanced J-2X rocket engine (a derivative [J-2] was originally used with the Saturn V rockets in the Apollo missions). After the first stage has been jettisoned, the J-2X is fired up to get Orion into orbit. The second stage is discarded, and will burn up upon re-entry into the atmosphere.

The Orion spacecraft also will be built as two unmanned versions. The first version will look identical to the manned version, except the crew module (CM) will be replaced with storage containers so that supplies can be brought, for instance, to the International Space Station (ISS), and experimental results and other materials can be returned to Earth. A third version will consist of an enlarged service module (SM) and docking system, which will totally replace the crew module (CM). This version will allow the ISS to be “boosted” into higher orbits.

Project Constellation will also consist of a Lunar Surface Access Module (LSAM) and a heavy-lift Ares V Earth Depart Stage (EDS), which consists of two modified-SRBs and a larger second-stage, which will look and function like a larger derivative of the Shuttle's ET. The EDS will lift the LSAM into space, which will then be assembled with the Orion spacecraft, which was lifted into space with an Ares I rocket, for its mission, for instance, to the Moon.

Although it is exciting to envision a manned mission to an asteroid, NASA’s first manned flight for the Orion spacecraft is still several years away. It is tentatively planned for 2014 or earlier, with a Moon mission by 2020.

More information about Project Constellation is contained at: http://www.nasa.gov/mission_pages/constellation/main/index.html.

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Science  Space  Space Station  William Atkins