I hear what you're saying, and I agree— it would be incredibly dangerous; a fool's errand... But aren't the true fools the ones who don't seize an opportunity, despite all the inherent risks? And I'd be able to show Steven the wonders of the cosmos! And maybe, just for a second, from a distance, I could see what's been going on without me.
The Crystal Gems and Steven arrive at a location filled with damaged warp pads. The Gems step on each warp pad, making sure they are inactive. Steven marks each inactive warp pad with a "Crying Breakfast Friends" sticker. He asks Pearl where all the warp pads lead to, and she explains that they used to be used for inter-dimensional space travel. All of them have, unfortunately, been deemed inactive for thousands of years. As she explains this, Pearl seems to lament the fact that she is stuck on Earth forever, but is comforted that she is there with Steven.
The next day, Steven watches "Crying Breakfast Friends!" with his father. Knowing how much Pearl misses space, Steven convinces his dad to help him build a spaceship for Pearl. Greg shows Steven his aunt and uncle's barn, which contains a large variety of scrap and machine parts. He explains that the couple had a great love for aviation, and they kept every single one of their belongings in the shed. Using the necessary parts needed from the shed, Greg and Steven build a small, measly, car-looking "space ship". Steven brings Pearl to the barn to show it to her. Before Steven tests it out, Greg tells him that he can always bail and that there is no shame in doing so. After Greg "lights the engines", he pushes the spaceship down the hill. As it progresses down, it begins to fall apart and Steven eventually jumps out. The ship races off and crashes into a rock, breaking apart. Pearl is disappointed, and lectures Greg and Steven on the proper design of space shuttles and ends up inspiring herself into building one of her own.
Through several montages, the trio uses leftover parts from the shed to build a prototype out of an upgraded engine and a hang-glider. After Steven tests it out and lands it (but purposefully falls apart), Greg discovers that Pearl is serious about taking Steven up into space. Refusing to let him go, Greg claims that he is "grounding" Steven, "grounding" as in he is not able to leave earth. Angry, Pearl decides that she will just do it herself, and disgruntledly shuts herself into the shed.
While Steven and Greg are sleeping, Pearl wakes Steven up to show him the new ship she built. Amazed, Steven climbs into the ship and Pearl suggests they take it out for an engine test. They excitedly start up the ship and launch into the sky. Greg wakes up due to the sound and blast of the engine and contacts the ship with his walkie-talkie. He tries to convince Pearl to land. Pearl tells him not to worry, as she is only going to take Steven to the nearest star system and will return him in 50 years, surprising Greg and Steven alike.
Up in the Earth's atmosphere, Steven witnesses continual damage to the ship and realizes that if they continue flying, the ship will be destroyed. He tries to convince Pearl to turn back. Yearning to visit space again, Pearl continues to push the limits of the ship. In a desperate attempt to get her to listen, Steven pulls the hatch release, ejecting the cockpit's window. He again tries to convince Pearl to abandon the ship, but she continues to persist. Steven grabs her head, and says, "Sometimes, you just gotta know when to bail". Finally listening, Pearl ejects them out of the ship just before it explodes. Greg is shocked to see the ship explode and scans the sky with his binoculars. After he spots them, he lays down in relief and curls up into a fetal position. As they float down to Earth in the parachute equipped ejector seat, Pearl apologizes to Steven for nearly killing him. He reassures her that he is used to it, and promises her that they will get into space one day. Pearl replies that she would rather stay on Earth. Steven says, "With me!", and Pearl, smiling, says, "Yeah, with you".
- "After These Messages"
- "UUU Fanfare / Let's Build a Spaceship: Part 1"
- "Blast Off!"
- "Let's Build A Spaceship: Part 2"
- "Almost There"
- Pearl's space uniform has a pink diamond on it. This could be leftover from the time when Pearl served Pink Diamond. The pink diamonds also appear on the shoes of Sardonyx.
- The Cookie Cat theme can be heard playing on the television after Steven asks Greg to help him build a space ship.
- This episode hints that Pearl does not like living on Earth, much like Lapis Lazuli, as long as she does not think about it too much.
- "Mach 3" meant that assuming the spaceship is nearing the end of Earth's atmosphere, the spaceship is able to travel at 3 times the speed of sound, or above 1000 m/s (meters per second). In other words, it can go about 5,880 mph (miles per hour).
- Assuming Pearl is referring to Alpha Centauri (and not an undiscovered star system even closer), a "popover" that would return within fifty years would mean that the ship can travel at roughly 17% of the speed of light, or 51,000 km/s (kilometers per second).
- When Pearl asks if any of the local stores carry F-1 single nozzle liquid-fueled rockets, she is likely referring to the Rocketdyne F-1 engines used in the first stage of the Saturn V launch vehicle during the 1960s and 1970s, mainly for the Apollo missions. This can be further supported by the fact that the F-1 is a single nozzle liquid-fueled rocket engine.
- In the modelsheets, the episode is named "The Space Race".
- The title is an allusion to the competition between the US and the former Soviet Union to launch a functioning spacecraft into outer space, during the Cold War.
- There appears to be an Apollo Lunar Module in the background of Greg's storage shed.
- The reference sheet on Pearl's tears is named "Ghibli Tears", an allusion to how the characters cry in Studio Ghibli animations.
- When Pearl plays her craft's keyboard console, the music is a direct reference to the "announcement" musical cue heard when waiting in line for Disneyland's Star Tours ride.
- Naming the experimental spacecraft "Mach 2" and "Mach 3" may be a reference to the Mach Five racecar from "Speed Racer".
- UUU could be a reference to the Land of OOO from Adventure Time, another show Rebecca Sugar has worked on.
- The Universe Mach 3 slightly resembles a British Aerospace T1A Hawk trainer jet. However, in the episode, the jet has a rounded cockpit, a fuselage smaller than an actual T1A, dual headlamps in the nose, collapsible wings and a rocket engine fitted in the place of the jet's vertical stabilizer.
- This is the first episode that the Galaxy Warp is shown, which is first mentioned in "Mirror Gem".
- This episode marks the second time Steven gets "grounded", but this time by Greg. The first time is by Garnet in the episode "Mirror Gem".
- Though, Greg's version of "grounding" is different, meaning that Steven is not allowed to leave Earth.
- The double meaning of "grounding" does not exist in many other languages, making Greg's line be altered.
- In "Last One Out of Beach City", Steven mentions that Pearl's reckless driving had made him the most scared since she "almost let him die", referencing either the events in this episode or the events in "Rose's Scabbard".
- When Steven faced Pearl when he said "I'm not supposed to go!" when they were in the spaceship, Pearl is seen wearing her post-regeneration outfit instead of her spacesuit, in the next scene, she is seen wearing her spacesuit again.
- When Pearl states that by going to space she can show Steven the "wonders of the cosmos," there is no patch behind the chair that Steven is sitting in. In the next scene, there is a sandy-beige patch behind the chair.
- When Pearl and Garnet are talking, Garnet's visors are the same color as the sky with stars on them, but in the next scene, they are back to normal.
View the episode's transcript here.