Could the Soyuz/Progress supply and crew a space station in Lunar orbit?

Question

The Soyuz launcher can put about a third of the mass in low Earth orbit compared with Proton, Falcon 9, Ariane 5, Atlas V. Is that enough to crew and resupply a space station in Lunar orbit, or at an Earth-Lunar Lagrange point, a so called Deep Space Gateway?

The delta-v from LEO to an EML points seem to be less than 1 km/s, but it took Saturn V about three days to ship three astronauts to the Moon, how long would it take for a Soyuz launcher, at less than a tenth of the capability, to do the same? And could the Soyuz spacecraft support the crew for that long? Could planned commercial spacecrafts like Dragon, CST-100 and Dreamchaser bring 3 (or 7) crews to a DSG? Or would it require the SLS with Orion to reach?

Answer 1

First, note that Soyuz launcher and Soyuz spacecraft are two distinct entities. The launcher is based on soviet strategic R-7 rocket, and all of its modifications are definitely not powerful enough to put its namesake spacecraft anywhere near Moon orbit.

Now, the Soyuz spacecraft is another matter. The Soyuz 7K-L1 spacecraft, in link with Proton launcher, was modified for testing if piloted circumlunar flight was possible, although the launcher was not man-rated. Zond-7 mission using this spacecraft was succesful in Moon flyby and returning to Earth, so it is possible to reach Moon orbit and return to Earth using modern, more powerful Proton launcher and a modified Soyuz vehicle.

Another mission was proposed in 2008 by Director of Russian NPO "Energia" Nikolai Sevastianov, based on original Korolev plan from 1964. It involved docking a standard Soyuz with separately launched booster module. This mission was slated for 2012, and as we know, never reached any results.

Answer 2

The question asks how long it would take. All "direct" trajectories to the Moon take about the same time -- 3 days. In principle you could shorten this by using quite large amounts of extra fuel (both to accelerate at the start and to enter lunar orbit when you arrive), but I don't think this has ever been done. You can also save a modest amount of fuel at the cost of a much longer flight by taking advantage of complicated interactions of the Earth's, Moon's and Sun's gravity, as was done for Hiten, which took five months.