Season 5 is a modded single-player game in Science mode, and one goal of the season is that no kerbal dies. The save opens on Year 2, Day 60 with 279.9 science and six flights in progress. Last time ended with BSSScience1, the first piece of a space station, still sitting in the Vehicle Assembly Building. This time it flies. Two empty test launches come first, then six kerbals ride it into orbit around Kerbin and get its labs working, and the first science from the station is sent home.
Bigger rockets for a tall ship
BSSScience1 is the middle of the station: the part people can return in, plus a stack of science experiments, RCS tanks, food and a small computer so it can be flown from the ground. "Yeah, it's very tall. We'll see if this thing tips over." The plan if it does: "we'll split this into two parts, fly them up, and then connect them together."
First, solar panels, four sets of them. Then the big job, getting it off the ground. Four huge fuel tanks go on the sides with large engines under them, more rockets go outside those, and struts and fins hold it all together. Fuel lines feed the outer tanks into the middle so every engine lights at once. A heat shield blocks the way between two sections inside, so ladders go on the outside for the kerbals to climb around it. That route is not tested before launch, and the jetpack is the backup plan: "If not, we'll use our jetpack in space."
Two empty test flights
The first test flies with no crew. "Oh, it's actually starting to take off." But the long middle swings back and forth on the way up. "It's like a happy dog." The struts had never been attached to the middle. When the outer engines drop away there is a burst of flame, and the flight goes back to the Space Center.
With more struts the second test is steadier, and it climbs into space with fuel to spare. "There's lots of fuel left, I'm gonna count this as a win." It is left behind. "Those things will crash."
Six kerbals aboard
This time the seats fill up. Jebediah Kerman, Valentina Kerman and Bill Kerman take the command pod, and Bob Kerman, Leatrey Kerman and Ludlie Kerman go into the Mobile Processing Lab MPL-LG-2. "I realize I have to feed them all, but I think there's a lot of food."
The rocket goes straight up until the side tanks run dry, then turns. Fuel runs low faster than on the empty test, "we added six people," but it reaches orbit, and the big tanks are let go.
Science in orbit
The solar panels open, and the scientists move into place. Not everyone can get through from inside, so kerbals go out on EVA and work along the ladder from one section to the next. What the commentary calls the particle accelerator starts up, the experiments open up, and the TH-NKR Research Lab starts making Eurekas. Power is the snag: on the dark side of Kerbin the batteries run flat. "I should've added more batteries." A future piece of the station is already planned as "a big battery."
To make time warp go faster, the orbit is raised to about 250 km. Then the experiments are cleaned out, rerun and sent home over the radio. The game counts it up: 21 science for Plant Growth, 38 for Retrograde Kuarqs, 80 for Prograde Kuarqs, and 63 for the lab's own research data.
Where it ends
The video stops in orbit around Kerbin with BSSScience1 and all six kerbals aboard, the lab researching at about 23 science a day. Nobody has been lost. The commentary's plan is to let it keep collecting, earn the science for one more docking part, build "a big docking hub" and connect more modules to it: "make this gigantic thing that crashes the game, that's the plan." The video ends with the lab window still open.