At this time, there has been no announcement of a scheduled unlicensed LEGO Space theme. LEGO is not going to make an announcement that "We forever and ever retired LEGO Space, and it will never-ever come back." It's just not going to happen. In addition, they don't reveal what they are working on, until it is time for an official announcement - usually ...
It's not a Star Wars set, it's most of the main part from "70704 Vermin Vaporizer" from the Galaxy Squad theme.
The word "pressure" on the green tile hints that it's not Star Wars, as that would normally be in Aurebesh - the written script you see in the films.
It turns out the curved white roof tile (Circle 90G 6X6 Roof Tile) at the front was only used in ...
It's hard to answer this definitively without a picture identifying the exact parts you have, but this sounds a lot like the set Rocket Base (358-1) from 1973:
That was one of the first space themed sets. The round parts are similar to what you've described. It looks like an obvious tribute to the Apollo program, though it isn't licensed or branded that ...
According to Brickset there were indeed stability problems with set #10213, which was originally intended to be a strictly display piece for the 16+ age group.
As a response, the 10213 was retired, and a reinforced version (#10231) has been sold instead. If you are stuck with the first, unstable edition, you could try applying these alternative instructions.
It looks like LEGO did not intend to make Shuttle attachable to ISS despite the statement. At least not with a stud-on-stud connection like the set is designed right now.
As seen in picture below, Shuttle is docked using a connection port inside storage bay with its doors open. Not sure if it is possible to replicate opened doors in scale Shuttle and ISS ...
What you have there is a 6118 Wheel Hard Plastic Small (22mm D. x 24mm), and this wheel is pretty common, it features in 39 sets, but luckily for you only in 4 sets in the color White. These sets are:
1704-1 Ice Planet Satellite Plow - this set has 6 of these wheels.
6983-1 Ice Station Odyssey - this set has 10 of these wheels.
6814-1 Ice Tunnelator - ...
928 was the original set number of the Galaxy Explorer - so the numbering of that one is following the LEGO tradition of using the set number.
As Joubarc points out, at that time the sets were branded LegoLand, which is where the LL comes from (in recent years LEGO often uses the Designer's initials).
I'd say that as Benny is a rather well used Classic ...
Although the stand-alone, unlicensed Space theme technically remains discontinued, LEGO has recently released an unlicensed Space sub-theme under their City theme.
While these builds seem to be more "near future" than the classic Space sets, they can be whatever you want them to be. This is LEGO we are talking about, use your imagination to figure out how ...
Couple of observations:
Neither of these pictures shows complete sets
The parts you show in each picture most likely do not all come from the same set
From what I can see, you have the following parts of sets in the pictures, clockwise from top left:
Parts of a Y-wing (likely 9495 Gold Leader's Y-wing Starfighter ) plus parts of 7166 Imperial Shuttle
Some of the places you can buy old (discontinued) sets include:
Generic on-line toy stores that carry old stock
Some LEGO discussion forums have areas for buying and selling
Toy shops and LEGO stores sometimes carry old stock
Stands at exhibitions and shows