A radioactive beam pins two cadets behind an atomic curtain.

Tom Corbett fights to clear his friend Astro of a negligence charge. Astro had given orders to a spaceship that somehow leads to its crash.

400 million miles from Earth, the cadets, Captain Strong and Commander Arkwright attempt to alter the course of an asteroid presently orbiting Jupiter. Their purpose: Find a way to force the asteroid around Ganymede, largest satellite of Jupiter, where it is to be transformed into a massive space station. Commander Arkwright has staked his reputation on this project. Failure means that he will feel compelled to resign from the Academy.

Major Bemus, the Space Academy Quartermaster, rejects the report that a defective feed line flutter valve for the oxygen tanks on Academy spacesuits is the cause of a series of accidents that could lead toward a fatal catastrophe. The Major's stubbornness is leading toward a fatal catastrophe.

The Space Cadets are assigned to a tour of duty at the Solar Guard's fleet anchorage, when one of the crew members is reported dead.

Tom and his unit brave danger against the solar system in a desperate effort to restore the life ray.

Pint-size T. J. Thistle is discouraged because he thinks he can't measure up to the man-size duties of the Polaris crew. Then the ship springs a fuel leak.

During a routine space run, T.J. Thistle and Astro are enthusiastically following by long-range televiewer, the attempt of Captain Cowan, famous Solar Guard rocket buster, to establish a speed record for a run around Titan and back. Tom has a more objective opinion of Capt Cowan. The Cadets suddenly see Cowan's ship explode, but Cowan miraculously survives, and is rescued by the Polaris crew. Cowan decides to take another try at the Titan speed record and manages to appropriate the Polaris and crew in spite of the objections of Capt Strong. Strong recognizes Cowan for the glory seeker that he is. On his attempt to break the speed record Cowman's recklessness endangers the ship and Cowan bails out leaving the Cadets to the mercy of the space debris near the rings of Saturn.

A fault-finding reporter arrives to investigate the Solar Guards asteroid station. His newspaper originally opposed the building of the project.

Tom Corbett and his shipmates try to find the source of the contaminated grapes which are causing radiation sickness throughout the colonies of the solar alliance.

On a trip to Mercury, the cadets are assigned to Major Connel, the roughest, toughest, meanest officer in the entire Solar Guard. This is much to the chagrin of T.J., who starts off by putting his foot in his month and just keeps getting in deeper. But the humor of this situation quickly turns to disaster when a technical error by T.J. puts Tom and the Major in a deadly situation and on the verge of perishing in Mercury's 700 degree heat.

The Space Cadets try to stop smugglers from sending supplies of hyperionite, a crystal that speeds up the breakdown of ores from space to Earth.

A former Solar guard Captain hijacks the Titan Mail Ship in revenge for his being dishonorably discharged from the Space Academy. Roy Cowan, the former "Ace of the Space Lanes" (see episode #8) returns, and this time he starts off by hijacking the Titan Mail Ship, leaving Captain Strong in dire jeopardy as revenge for his having been discharged from Space Academy. He then teams up with a weapons specialist who was also discharged from the Academy. They go on a devastating rampage, destroying other ships that they come across at random. The Polaris Crew offer themselves as bait to trap Cowan. Cowan comes after the bait with a vengeance.

The Polaris Cadets are in trouble for an accumulation of minor infractions so for a period of 31 days they are assigned to what is supposed to be a tedious Cargo detail as punishment. But on their first run they find a part of their cargo to be alive. The Polaris crew is assigned to take a chimpanzee to a zoo at Venusport, and the chimp proceeds to make monkeys out of the Cadets.

An accident on board the Polaris cuts Astro adrift from the ship, and he floats in a panic, through the blackness of space. Tom and T.J. must rescue him and calm his fears. Psychological damage from the experience is more devastating than the physical harm, and Astro learns that he may "never see space again". T.J. Thistle has his own ideas of providing Astro an instant cure. But a meteor striking the Polaris provides a better method for bringing Astro around.

The Space Cadets board a spaceship to return from a vacation. Little do they know that its Captain plans to abandon ship and collect the insurance covering its loss.

A strange asteroid having an exceptionally strong magnetic field, along with the magnetic personality of one, T.J. Thistle, combine to wreak a hit of havoc in space. Tom warns T. J. Thistle that there must be cooperation between the crews of the Polaris and the Sirius if they are to track down the magnetic asteroid. But T. J. wants to carry on his feud with the rival ship.

Tom Corbett and his buddies are trapped aboard a training ship on its test flight. The ship is supposed to pass through the asteroid belt.

A false distress alert from outer space sends Tom Corbett and the crew of the Polaris rocketing into an almost certain death trap.

The Polaris Cadets, Captain Strong, and a very obnoxious Cadet Monroe, are assigned to retrieve data from a robot rocket referred to as the "Deep Space Projectile", in the vicinity of the star Sirius. While docking with the Projectile a malfunction causes the Projectile to break away fro the Polaris and T. J. and Captain Strong find themselves spiraling in toward Sirus a white star 2.35 times as massive and 23 times as luminous as our Sun.

Tom, Astro, and T.J. make a stop at an outpost on Triton, the largest satellite of the planet Neptune. The first thing they discover at, the outpost is a corpse. The unfortunate victim appears to have died of radiation.

Secretary Masters, the top Man in the Solar Guard, pays a visit to Space Academy and receives an unfavorable first impression of the Polaris Cadets. Later, as a part of an exercise, and to impress Secretary Masters who is aboard the Polaris and to atone for their previous embarrassment, the Cadets must knock out a robot rocket in Mars orbit. They hit it as planned, but the robot rocket careens wildly out of control, posing a deadly threat to other ships. The Cadets voluntarily risk their necks to try to stop it.

Roy Cowan, a former solar guard Captain, escapes from the Asteroid Prison and sets out to ambush the Polaris. His aim: to destroy Tom Corbett and his crew mates who twice before foiled his bid for fame and glory. Two convicts, including the treacherous Roy Cowan, escape from the Prison Asteroid by hijacking a space freighter. Cowan and his accomplice lure the Polaris Cadets into an ambush using their hijacked freighter as bait, which they themselves have abandoned, but not before starting a wildcatting reaction in the freighter's reactors, which will cause the ship to explode as the Cadets approach.

The young daughter of the Defense Minister stows away aboard the Polaris. She causes trouble for Tom and the crew who are headed for Titan to field test a new reactor.

Tom, Astro, and T.J. are assigned to fly an old ship to Venusport, where it is to be scrapped. But as the Cadets are descending toward Venus, the ship's reactors malfunction, sending it crashing into the Venusian jungle, as the Cadets bail out to survive. Then they must work to survive again in the midst of a Venusian jungle, while all the time an unseen volcano threatens to erupt and they must use the survival techniques learned at the Academy.