The United States plans to return to the Moon within 12 years, as part of NASA's Project Constellation. A new series of launch vehicles and spacecraft are being developed to get humans back to the Moon by the year 2020. The launch vehicle, Ares, will use both solid- and liquid-fueled rocket stages. The spacecraft Orion will
be an enlarged version of the Apollo Command Module, with a crew capacity of up to six for Earth orbital flights, or four to the Moon. Similar to the Soyuz spacecraft, the Orion Service Module will include deployable solar panels. Similar to the Space Shuttle, the Ares boosters will be reusable solid-propellant rockets, extended to five segments. Similar to Apollo, the upper stages will use liquid propellants powered by the new J-2X engine, an outgrowth of the old Apollo J-2. Unlike Apollo, each Lunar mission will involve two launches and a conical Crew Module that can be reused up to ten times. Although original plans called for a parachute landing on dry land, the plan now is to splash down in the eastern Pacific, much like Apollo.
As of this writing, the Lunar Return Flight Plan looks like this. An unmanned Ares V rocket (Fig. 10.7) lifts off from Cape Canaveral with a fully fueled Earth Departure Stage (EDS) and a Lunar lander called a Lunar Surface Access Module (LSAM). The LSAM is made of two modules, just like the Apollo LM. These modules are placed in LEO to await the arrival of the crew. Shortly after, an Ares I rocket with an Orion spacecraft and crew of four lifts off and rendezvous' with the
Fig. 10.7 Ares V unmanned rocket, used to launch heavy loads, including Lunar transfer stages and Moon landers. The smaller Ares I (Fig. 2.7) will launch astronaut crews (courtesy NASA)
unmanned vehicle. Orion docks with the EDS and LSAM (Fig. 10.8), upon which the combined spacecraft rocket to the Moon using the EDS engine. Similar to the S-IVB, the EDS is cast adrift after expending all its propellants. Similar to Apollo, there are now four modules coasting uphill to Luna. Unlike Apollo, docking with the Lunar lander takes place in LEO before the EDS burn rather than on the way to the Moon after the S-IVB burn. Upon reaching the far side of the Moon, the LSAM's engines, instead of the Service Module engine, are used to brake the docked spacecraft into orbit. Next, all four astronauts transfer into the LSAM and descend to the Lunar surface for about a week of exploration and surface activity, leaving the empty Orion in Lunar orbit. In Apollo, the Command Module pilot remained in Lunar orbit while the other two astronauts explored the surface. The LSAM will be an enlarged version of the Apollo Lunar Module, with a four-legged descent stage and a manned ascent stage. Instead of a single engine in the descent stage, the LSAM will have four engines, as well as a single engine of the same type in the ascent stage. Similar to the LM, the LSAM is to be used one time only. The landing sites will be near the poles, in hopes of finding water ice in those regions. Similar to Apollo, there is a conspicuous lack of in-space refueling.
What is original about the Ares/Orion Lunar landing plan? Well, the Crew and Service Modules are virtual duplicates of the Apollo CSM, enlarged and upgraded
with better computers, fan-shaped solar panels, and reusable up to ten times. The LSAM (Fig. 10.9) is a beefed-up version of the Apollo LM, with the addition of three more rocket engines in the descent stage, but not refuelable or reusable. The EDS is the equivalent of an enlarged S-IVB, even using the same J-2 engine upgraded to J-2X. The launch escape tower is Apollo-era technology, and the SRBs are borrowed from the Space Shuttle, lengthened by one segment. The answer is nothing. Not even the procedures are new. Nothing is being done for the first time. The Apollo program, including the precursor Mercury and Gemini projects, invented almost everything: man in space (women in space had to wait for the Space Shuttle, Valentina Tereshkova notwithstanding), extravehicular activity or "spacewalks," orbital rendezvous and docking, ablative heat shields, splashdown and recovery operations, and landings on the Moon. Project Constellation presents nothing new, not even in-space refueling. This means that as each module runs out of propellant, it becomes a useless hollow hulk, a space derelict. Project Constellation will, however, almost certainly take the first women to the Moon, which is noteworthy.
The only components of Project Constellation that are planned to be reusable are the solid rocket boosters and the Orion Crew Module (Figs. 10.10 and 10.11) . Compared to Apollo, this is laudable. The Ares/Orion spaceflight concept will be much safer and simpler than the Shuttle. If anything unfortunate happens during liftoff, the launch abort system (Apollo had a launch escape system, same thing) will activate and accelerate the crew capsule safely away from a malfunctioning booster. Also, with Orion perched at the top of the stack, the danger from falling debris has been eliminated. But it is still missiles and modules.
Fig. 10.11 The Orion Crew Capsule enters Earth's atmosphere prior to splashdown at sea or "bump-down" on dry land. Either way, large parachutes are required because the return module has no wings (courtesy NASA)
Was this article helpful?