Sydney, Mindy, Sunspot, and Sean help Jet cook a classic meal from Bortron 7 for his parents, Celery and Carrot. After some funny attempts, the kids find that using the Scientific Method works best to get the meal done in time.
Jet attempts to play the "Solar System" game with Sean, Sydney, and Mindy, but the kids don't quite understand which planets go where. Celery, Jet's mom, takes them on a tour of the solar system and introduces each of the eight planets.
Jet explains how his family, the Propulsions, found Earth by way of the Sun, a star in the Milky Way galaxy. Celery takes the kids out into space and shows them how the Sun looks huge, or small like other stars, depending on your perspective.
Sydney, Jet, Sunspot, and Sean fix up a treehouse and make it into their own clubhouse/observatory. The kids even build their own telescope so they can all observe the awesome nighttime sky!
The kids learn how all the planets both orbit around the Sun and rotate on their own axes at the same time.
Jet attempts to grow a seed from his home planet, but the light from our Sun is stronger than the light from Bortron 7, and has a surprising effect on the plant!
Sean explains to the others that Earth is a "Goldilocks" planet because it's not too hot and not too cold. When Celery takes the kids to space, they observe how the other planets don't have the right attributes to support life, but Earth is "just right!"
Jet, Sean, and Sydney visit their Mars Robot Rover friend at the DSA, and discover that the rover seems tired. Through helping the solar powered robot regain its energy, they learn how energy can be captured, used from the Sun, and used anywhere - even on Mars.
Led by Sydney, the kids build a moon base in Jet's backyard and use their imaginations to figure out what challenges they would need to overcome in order to live on the Moon.
The kids take a trip to the Moon and learn that falling asteroids probably created all the craters on the Moon's surface!
When Jet, Sydney, and Sean have a hard time trying to explain the phases of the Moon to Mindy, Jet's parents, Celery and Carrot, offer to fly them out to space so they can see how the Moon changes shape depending on perspective.
Jet, Sydney, and Sean decide to have a sleepover in Jet's backyard. They use Sean's telescope to look at the night sky and learn why stars twinkle and planets don't.
Sean tells Jet, Sydney, and Mindy about the Apollo 11 mission, and the kids decide to do a real-life reenactment of man's first mission landing on the Moon!
Jet gives a special birthday gift to Mindy that allows her to defy gravity. She has so much fun hovering above everyone, the others have to convince her to come back to Earth in time for her party.
Beep is sad because her sister rover on Mars, Boop, is sick and can't move. Celery flies the kids out to Mars to try to help and discover the problem - that Boop's solar panels have been covered in dust.
Jet learns what chores are, and he and Sean help Sydney turn her chores into science games!
Celery and Carrot need to update their guidebook about Mars, and the kids join them on a trip to see how much things have changed on Mars in the last four billion years.
Jet builds a robot version of himself, so that he can be in "two places at once!" But Jet learns what jealousy is when the other kids seem to be having more fun with Jet 2 than they are with him!
Mindy is shocked to learn that there is more than one moon in the solar system. Celery flies the kids out to Mars so they can see what its two moons look like compared to ours.
Sean and Sydney take Jet to meet Sean's mom, a scientist, at the Deep Space Array. She explains that they're looking for stars with their own systems of exoplanets to detect if there might be any that contain life. But will taking Jet out in public expose his secret identity?
When Jet and Sydney interrupt Sean doing some training in his backyard, it leads to a pretend mission to Mars.
Sean is trying to work on a science project for Space Troops, but is interrupted by his friends' constant noise.
Celery takes Jet, Sydney and Sean to Saturn to learn what its rings are made of.
Sunspot goes missing
The Propulsions travel to Mars to explore Valles Marineris, which is the largest canyon in the solar system.
Sean and Sydney take Jet to see a show at a planetarium.
Celery's brother, Zucchini, becomes lost while on his way to visit the Propulsions.
A major storm on Saturn is mistaken for a storm on Earth.
Sean sets up a sno-cone stand to help raise money to send a spaceship to Mars. But it's the hottest day of the year and he quickly runs out of ice, and he can't find any nearby. Then Jet has an idea where they can go to get some ice-Saturn's ice moon, Enceladus!
Jet builds a mini-flying saucer in his garage and wants to test it, but to succeed, he has to learn what gravity is and how it works.
Mindy and Carrot want to make desserts that represent the different planets of the solar system for a cooking competition, but can't remember whether Saturn is hot or cold.
Jet builds an electric engine from scratch for the annual soapbox derby competition, but Mitchell, determined to win the derby, is suspicious that Jet is using some alien technology.
When Mindy and Sunspot are digging in the yard, they discover a unique rock that Mindy is convinced is a meteorite.
Sean's determined to beat his mystery competitor at a video game of "Astro-Tracker." He realizes that the best way to learn about asteroids is to see them for himself.
Sean sets up an asteroid watch-station in the treehouse.
Mindy spots a possible new comet.
Sean, Sydney, Jet, and Carrot head out to view the Northern Lights. Mindy, upset she can't go, gets a boost - Sunspot stays back and agrees to let her be his pet-sitter.
When the kids realize that they all want to use the treehouse at the same time for different activities, arguments break out.
The kids rely on an old Earth computer while FACE 9000 is being upgraded.
When Jet realizes that it’s the anniversary of Carrot and Celery’s first date, he wants to recreate that first picnic they had on one of Bortron 7’s moons. The kids all get involved to help create the perfect date night.
Mindy worries about a new addition to her family.
Mindy is excited about showing off her Pluto model at a school show.
The kids and Celery help Sunspot get to Jupiter for his Red Spot Club meeting.
Uncle Zucchini learns about the three states of water (solid, liquid and gas).
The kids learn about the Earth's layers while attempting to dig into the planet's center.
A sweet smell keeps Mindy up at night.
Sean wants to be like Neil Armstrong.
Mitchell learns about the "black hole" kitchen counter.
A recap of the Propulsion family's mission to Earth.
Mr. Petersen and Mitchell accompany Carrot and Jet on a camping trip.
Jet tries to fix a TV satellite.
The kids want to take a "satellite selfie" the next time a satellite passes over their neighborhood.
The kids learn about recycling.
The kids hold a paper airplane contest.
The kids learn how scientists use satellites to communicate between Earth and Mars.
The kids explain to Mindy how stars are labeled and identified by constellations.
Part 1 of 2. The new version of the saucer dashboard's OS malfunctions.
Conclusion. The new version of the saucer dashboard's OS malfunctions.
Mindy, Jet, Sean, and Sydney use a solar panel to improve their energy efficiency and notice that Sunspot is acting strange.
NASA's "Year in Space" program on the International Space Station inspires Sean to try to live for a year in the tree house.
In this special half-hour episode, Sydney, Sean and Mindy help Jet experience his first Halloween – from carving Jack-o-lanterns and dressing up in costumes, to trick-or-treating and going to a haunted house. Along the way, the gang learns about lunar eclipses and the Red Moon.
The kids and Sunspot attempt to build the tallest tower ever on the moon and are surprised when the moon's surface shakes.
The kids try to train Jet to act less like an alien from outer space.
As the kids get ready for Valentines Day by making their own valentines out of paper, Mindy continues to feel sad that little, frozen Pluto is so far out at the edge of the solar system. When Sydney shows Mindy a newly-downloaded, full-color image of Pluto as seen by the New Horizons spacecraft, Mindy is intrigued by Pluto's 'heart' of ice. Mindy once again feels that Pluto deserves our love, since it's no longer considered a planet, but is orbiting out there at the edge of our solar system, like a big frozen Valentine. She asks Sydney to bring her own little hand-made Valentine to Pluto on her behalf. Sydney leads an expedition of the kids to Pluto to bring Mindy's Valentine, experience the frozen dwarf planet themselves, and bring back their report to Mindy.
Sydney is directing the kids in a backyard movie, making her version of a Commander Cressida story about the formation of a star. The other kids all have parts, but Sunspot has the lead - as the star! The kids' movie coincides with the celebration of a star being born near (a.k.a. 10 light years away from) Bortron 7!
Mindy's mom gives her permission to venture farther out in the neighborhood.
Sydney tells Jet a story about a Boxwood Terrace pioneer known as Lone Star.
Jet tests his first time machine so that he and his pals can go back in time three minutes and catch a spectacular moment in a meteor shower that they missed.
Jet, Sydney, Sean and Sunspot join Celery as she competes against Uncle Zucchini in a race.
A song helps Sean overcomes his nervousness about flying to Neptune.
The kids throw a party for Jet when they learn they missed all 63 of his Bortronian birthdays.
After an afternoon on the Moon, Celery, Jet, and Sunspot discover, as they fly to Earth, that they have mistakenly left Carrot on the Moon! Then the saucer malfunctions and they receive news of a possible solar storm headed their way.
When a loud thunderstorm hits the neighborhood one evening, the Propulsions are woken up. They gather in the kitchen as the noisy storm rages on, and Jet is too excited to get back to sleep. Carrot, Celery, and Sunspot are sympathetic - they're in the same boat! During the night they all learn about Earth storms as compared to storms on other planets. And then they all try to get Jet to fall back asleep, a seemingly impossible task.
The kids create a makeshift "Day in Space" for Mindy as they watch and learn about the Leonid Meteor Showers.
The kids travel to outer space to confirm that there is no sound in there.
Sydney shows Jet and Sean a cool experiment - dropping different items from the same height to see which reaches the ground first. That reminds Sean of a video he watched of an astronaut on the Moon dropping a hammer and a feather from the same height. They reach the ground at the same time. And the reason is atmosphere - or lack of it - on the Moon. Jet laughs - really? Wait, what's atmosphere? Well, the kids know the best way to find out - into the wagon/saucer! Our kids and Celery fly to the edge of the Earth's atmosphere to learn what it does... and then go to the Moon. Is the atmosphere around the Moon the same as the Earth's? And what happens when our kids do the hammer-feather drop on the lunar surface?
Sydney brings Jet and Sean to the DSA to visit her mom, Dr. Amy Skelley, and check out her work. Dr. Skelley is a robotics engineer who makes outer space robotic and gadget dreams a reality.
Celery takes the kids on a saucer tour all around the Earth to discover all the ways that water can be found. They visit Antarctica to look at the ice, and then compare that extreme to the icy surface of Jupiter's moon Europa.
Sydney wants to enter a Commander Cressida story contest, but can't think up a good enough story. The other kids help, and they come up with a story about lassoing a comet to bring water to Venus, and then Mars.
The kids do a bunch of projects in the treehouse, but they leave a lot of trash and no one wants to take responsibility for it. They learn to share the responsibility for keeping the treehouse clean.
Mindy tells Jet that clouds are made out of cotton balls. Jet, of course, believes this, but Sean and Sydney don't. Mindy says she learned this from Lillian. The kids go to Dr. Rafferty and Dr. Skelley, who teach them what clouds are really made of and how to find correct information.
The kids play shadow tag but clouds cover the sun, ending their game. The kids learn about a planet with three suns, Proxima B, and travel there see how having three suns affects their shadows.
Sean presents a magic show for the kids (and Carrot). After impressing them with a string of paperclips seemingly held end-to-end by an unseen force, he explains that the trick was done with a magnet he held in his hand. The kids decide to investigate how and when magnets work, and then use their knowledge to put on another magic show for Carrot.
It is Carrot's 250th birthday, so the kids make a circus to celebrate. The kids can't do their stunts on Earth because of the high gravity so they move the circus to the moon, where everyone can do their circus tricks due to the low gravity.
On Earth Day, the kids decide to make posters to celebrate. The kids travel around the Earth to find out what makes Earth so special.
