The Dyson Dilemma: A Warp21 Adventure (15 pages, free at DriveThruRPG) is a fun sci-fi adventure for Warp 21 RPG, but I used Doll house D.R.A.M.A. (31 pages, free/pay what you want, same place). I used Four Colonial Marines Against the Darkness of Space (48 pages) as my solo engine. I created four first level characters.

The adventure started with the PCs going to a meeting. They are in an elevator when it stops working. Jana gets out her tool kit and redirects power to the elevator system. It is now working and the PCs get to the meeting. The mission is explained to them, rewards are discussed, and it is agreed that they will get promotions if they can get Sphere Control to work properly. At this point, Garfield the NPC wants to play a gambling game. Tara attempts to use her beauty to get the secret from him. Her attempt fails. She whispers her secret into his ear. Jana successfully pilots their ship to Sphere Control. They start to explore it and Tars searches for something useful. She fails.

In the Communication Room they find Boro the NPC and they talk to him. He does not want to cooperate, so they leave him there. In this same room, Kim repairs the radio. In a long hallway they find a dead scientist with a scalpel in his hand. They use their skeleton keycard to get past a locked door. Soon they encounter the plant menace. Jana is able to get around it and rescue Dr. Roberts. She uses her acid on the heart of the plant menace and kills it. Next, they go to the mainframe and Kim resets it. They successfully get back to Nexus station and get their promotions.

Note - It took me about an hour to create the characters and about two hours to go through this fun adventure.