The ISS partner agencies have initiated a study into staging a manned flight to the Moon from the ISS: [Manned flight around Moon considered – BBC News].
> Using the station as the spaceport, or base-camp, from where the astronauts set off on their journey is part of the new philosophy being considered.
“We need the courage of starting a new era,” Europe’s director of human spaceflight, Simonetta Di Pippo, told BBC News.
“The idea is to ascend to the space station the various elements of the mission, and then try to assemble the spacecraft at the ISS, and go from the orbit of the space station to the Moon.
“What we are thinking about right now – but again we need more technical work to address this – [is] it should be a small spacecraft that goes around the Moon.”
This vehicle would then likely return straight to Earth, rather than returning to the ISS.
Note that there have been various proposals over the years for staging lunar missions from the ISS. For example, in 2006 [Constellation Services] proposed the [_Lunar Express_] concept, which would have a Soyuz spacecraft at the ISS dock with a logistics module that would drive the system on an Apollo 8 style swing-by of the Moon. Here is a presentation about the idea: [CSI’s Lunar Express System” A low-cost manned trip around the Moon in 3 years or less – by Benigno Muniz – NewSpace 2006 Conference – July.20.06 (pdf)]
**Update**: Rand Simberg notes that this undercuts arguments for the necessity of a HLV for beyond-earth-orbit activity: [Not Waiting For A Heavy Lifter – Transterrestrial Musings].
: http://www.bbc.co.uk/news/science-environment-11304559 : http://www.constellationservices.com/ : http://www.constellationservices.com/lunarexpresssmsystem.html : http://www.constellationservices.com/Lunar_ExpressSM_system_brief_NewSpace2006_20_July_2006.pdf : http://www.transterrestrial.com/?p=29782