Lunar orbital station, LOS
To establish a permanent foothold on the Moon, earthlings would need more than a single piloted spacecraft. As in past conquests of remote and inhospitable lands, it might be necessary to pre-position supplies and accommodations along the way.
A lunar lander (foreground) arrives at the lunar orbital station, LOS (center). After a successful docking, the crew, which arrived at the LOS onboard a separate transport ship (background), will board the lander for the final leg of its journey to the Moon. The ascent stage of the lunar lander from the previous sortie to the Moon can be seen parked at the peripheral docking port of the LOS. Copyright © 2008 Anatoly Zak
Way station on the road to the Moon
The most convenient location for a way station on the road to the Moon, would be the lunar orbit. Here, landers returning from the surface of the Moon would link up with transport ships coming from Earth. Crews and cargo could be exchanged and large quantities of propellant could be accumulated for specific “high-power” missions, such as the delivery of heavy lunar base modules to the surface of the Moon. (138)
The concept of a lunar orbital station, or LOS, appeared in early American and Soviet studies of lunar exploration. As early as 1959, Wernher von Braun envisioned the refueling of transport ships in the lunar orbit, in order to facilitate the construction of a lunar base within the project Horizon. In 1962, Sergei Korolev, the founder of the Soviet space program, considered the possibility of establishing long-duration "satellite-stations" in lunar orbit with the goal of supporting deep-space expeditions. (137) The idea was further evaluated around 1963 within the L4 project.
In April 1971, North American Rockwell proposed a concept of an eight-person lunar orbital station. It would be first inserted into the Earth orbit with a help of the Saturn-5 INT-21 rocket, where a visiting crew would prepare it for a trip to the vicinity of the Moon using the nuclear-powered space tug.
Still, for most of the 20th century, a lunar orbital station had remained a “luxury” item at the bottom of on priorities list in the contemporary space programs. The concept was impossible to justify within the limited scope of lunar exploration at the time. However, the first decade of the 21st century saw a renaissance in lunar exploration plans, with rocket scientists on both sides of the Atlantic dusting off their ideas for establishing a permanent presence on the surface of the Moon. In the post-Soviet Russia, planners at the country’s leading manned space flight centers – RKK Energia and Khrunichev enterprise – saw a lunar orbital station as an essential element in the Earth-Moon transport chain.
Khrunichev’s LOS concept
On November 14-15, 2007, the Gagarin Cosmonaut Training Center in Star City hosted the 7th scientific conference on manned space flight. Sergei Pugachenko, a representative of KB Salyut, the development arm at Khrunichev enterprise, revealed ambitious long-term plans for exploration of the Moon and Mars.
The lunar infrastructure proposed by Khrunichev included two major elements – a base on the surface of the Moon and a lunar orbital station. Pugachenko’s presentation included a slide, which was perhaps the first depiction of a possible configuration of the lunar orbital station, LOS.
The spacecraft clearly traced its roots to the generations of Soviet space stations, such as Salyut, Almaz, Mir's core module and the service module of the International Space Station. Not coincidently, all these vehicles were built at Khrunichev. LOS sported six docking ports, high-power antenna for communications, maneuvering and attitude control engines, solar panels and a robotic arm, similar to the one developed by the European Space Agency, ESA, for the Russian segment of the ISS.
In an accompanying statement to the media, Pugachenko explained that the lunar orbital station would be used for the transfer and storage of cargo and propellants, as well as serve as temporary or emergency quarters for crews and a platform for scientific studies of the Moon, such as remote-sensing and cartography. LOS could also help relay signals between Earth and the lunar surface.
Both the lunar surface base and the lunar orbital station would be delivered into space by a super-heavy version of the Angara rocket with a cargo capacity of 100 tons to the low-Earth orbit. To top it off, Khrunichev drafted a family of giant rockets, with a cargo capacity to low-earth orbit ranging from 45 tons to an incredible 175 tons!
Animation of the lunar lander docking to the lunar orbital station, LOS. Click to play: Streaming QuickTime / 20 seconds Copyright © 2008 Anatoly Zak
Artist rendering of the Lunar Orbital Station, LOS, based on the line art presented by Khrunichev enterprise in November 2007. The depiction of the lunar lander is based on studies by RKK Energia and Keldysh center, the drawing of the manned transport ship is provisional and based on descriptions available at the end of 2007. Click to enlarge. Copyright © 2008 Anatoly Zak
In 2015, RKK Energia formulated several concepts of a man-tended habitable platform in the lunar orbit. Click to enlarge. Copyright © 2016 Anatoly Zak
Circa 2015 concept of a near-lunar station assembled of Russian-built modules delivered as piggyback payloads on NASA's Orion/SLS system. This particular configuration was developed at RKK Energia under a contract with Lockheed. The concept was also presnted to an international group working on advanced concepts. Click to enlarge. Copyright © 2016 Anatoly Zak