OK, this might be complete, unless someone points out a change that I agree with (quite possible):
Space Agencies of the Great Powers
USA: The National Advisory Committee on Aeronautics is not so much a space agency in and of itself, as a coordinating agency for the various US space programs (Army Rocket Artillery Corps, Naval Research Laboratory, NOAA Satellite Office (which mostly uses NRL launch vehicles), Post Office Department Rocket-Mail Service, et cetra), relaying information between them and making them work together. It is only the lead agency on big projects like the space station, Moon Landings, and Project Ares (preparing transportation and infrastructure for a retaliatory invasion of Mars), where the individual agencies each do separate parts of the work, to avoid wasting money and other resources on duplicated effort.
Croatoan, the USA's space station, is the largest by overall volume. Their current plan for the Moon mission is to assemble a modular rocket at the space station (having a separate lander and command module), and send it to the Moon directly once complete.
UK: The British Interplanetary Society was originally an independent body of enthusiasts and a few gadgeteers, depending financially on donations and later on launch fees once they'd proven that artificial satellites were viable. In 1933, after Ming's attack, the BIS made an agreement with the incoming First MacAdder Government, accepting a significant amount of government money in return for allowing His Majesty's Government to appoint some members to the BIS Council and have final approval of new Directors, thus strongly influencing the Society's agenda (becoming approximately what modern Homeline's UK would call a
qango). The MacAdder Governments ran things with a fairly light hand, but Chamberlain has become quite concerned since being informed that the Second Martian Invasion is on the way. He has appointed Winston Churchill and Lord Blackadder to the Council, neither of whom is particularly inclined to sit quietly. Britain's Space Station
Victoria is the largest by habitable volume, partly due to being the oldest. Their current plan for the Moon mission is to put a space station with a lander or two into Lunar orbit, and shuttle between the Earth-orbiting station and the Moon-orbiting station.
Germany: The SS-Raumabschnitt, founded in 1933, is the only national space agency that is technically responsible to a political party rather than the government, though by this point there is little difference between the Nazi Party and the government of the German Third Reich. Prior to the creation of the SS-Raumabschnitt, the Luftwaffe had been trying to establish a space program, but never quite received the budget for it. This has lead to an increase in the dislike between the SS and the Wehrmacht, particularly as Hitler's and Himmler's plans for the invasion of Mars involved the Waffen-SS being in overall command, with at best a few Wehrmacht units placed within Waffen-SS battalions. Their current plan for the Moon mission is similar to the American plan, save that the lander and the command module will be a single vehicle, with only the main fuel tank and connecting truss being separate (to be ejected once spent).
USSR: The Soviet Rocket Forces are a full military branch, like the Red Army and the Soviet Navy, responsible for space warfare, and the military use of rockets considered too heavy to be carried by two men in the field. They have the largest space station by mass, and are believed to have the most launch failures, and the most casualties in orbit (though as they do not report them, it is difficult to be sure). Their current plan for the Moon mission is basically the British plan, though delayed due to manufacturing difficulties.
France: The French Ministry of Space was founded in 1930, largely as a matter of national pride (which had been stung by the BIS getting a satellite into orbit). Their space station is, much like the German station, very middle-of-the-road. Their current plan for the Moon mission is ambitious: a series of unmanned landers will go first carrying supplies, followed by a dangerous Direct Ascent with a single large manned rocket (though refueled at the French space station). This vehicle will not have the fuel for an Earth Return, and thus will become the first component of the French Moonbase; they will then keep sending supplies while the gadgeteer on board builds something to get the crew home (they already have too many mad scientists volunteering for this).
"L'audace, l'audace, toujours l'audace!"
Italy has a complicated (but politically reliable) arrangement of space programs, theoretically under the Regia Aeronautica Italiana, though drawing personnel and resources from the Ministry of Public Works, Ministry of the Colonies, Ministry of Corporations, and lesser influences from anyone else who can find an excuse. The best that can be said is that they aren't working against each other, and their space station leaks less than the Soviet station. Their current plan for the Moon mission is basically the German plan.
Japan has two rival space agencies, one run by the Imperial Japanese Army and one by the Imperial Japanese Navy (who hate each other to the point of actively sabotaging each others' programs and assassinating each others' officers), and no effective means of making them work together. This has left them mostly on par with Italy (despite having two functional space stations to Italy's one, as the stations they have are smaller; the IJA's station is slightly bigger than the IJN's), when a single program with the combined resources of the army and navy programs would be a match for the BIS. The army's current plan for the Moon mission is roughly identical to the British plan, while the navy's plan is very similar to the French plan, despite this requiring an expansion of the IJN's space station to allow sufficient fuel storage.
Brazil, while technically a middle power or a major regional power, has a sufficiently robust space program that it would be reasonably accurate to call them a Great Power when discussing space. The National Institute for Space Research is roughly on par with the French Ministry of Space, save that their plan for Moon missions is to first see what happens when others go, and then make plans to avoid the mistakes that more hurried powers made. Their space station is quite new, but is already bigger than Italy's.
Thoughts?