Synopsis

The story takes place in the year 2025, after Earth has welcomed alien  beings to live peacefully with the human race. However, peace is short lived as the planet-conquering Troobian Empire turns its destructive attention to Earth. When the Earth's first line of defense, the S.P.D. A-Squad, vanishes without a trace, the protection of the planet falls to their replacements: the B-Squad Rangers, and their dog-like alien commander, Anubis "Doggie" Cruger.
When two reformed thieves join the team as the Red and Yellow S.P.D.  Rangers, tensions threaten to tear them apart. With the alien threat growing stronger every moment, the Rangers must put aside their differences and go into action as one.
Using teamwork, intergalactic weaponry and light-speed Zord vehicles to battle evil, they unite to become one of the ultimate forces for good: Power Rangers Space Patrol Delta.

S.P.D. Rangers

Main article: S.P.D. Power Rangers

The main team of S.P.D. Rangers are members of the Earth Branch's B-Squad.

Jack Landors

The S.P.D. Red Ranger. He was originally a criminal on the run from S.P.D., until Doggie Cruger chose him to be the Red Ranger. His genetic power was molecular phasing: the ability to pass through solid objects. At the end of the series, he retires from S.P.D. service to assist in helping the needy, and Sky becomes the Red Ranger. He was portrayed by Brandon Jay McLaren.

Sky Tate

The son of a former Red Ranger, he wanted all his life to be the Red Ranger but was chosen to be the Blue Ranger and second-in command. He very rarely strays from the rules. His genetic power was the ability to create force fields. At the end of the series, his dream of being the S.P.D. Red Ranger is fulfilled. We find out later in an episode of Power Rangers Operation Overdrive (Once a Ranger) that Commander Cruger "Doggie" has been promoted to SPD Supreme Commander following the retirement of former Commander Fowler "Birdy", and Sky has been promoted to Delta Base Commander. He was portrayed by Chris Violette.

Bridge Carson

The S.P.D. Green Ranger; the strangest of all of the Rangers. To clear his mind, he does a headstand. His genetic power was the ability to scan other's auras, a form of psychometry. At the end of the series, he is promoted to Blue Ranger, as Sky was promoted to Red Ranger. In an episode of Power Rangers Operation Overdrive (Once a Ranger), we find out that because of Sky's promotion to Commander, he is the new B-

Squad Red Ranger. He was portrayed by Matt Austin.

Elizabeth "Z" Delgado

The S.P.D. Yellow Ranger; she, along with Jack, were on the run from S.P.D. until she decided to take up Doggie Cruger's offer of becoming the Yellow Ranger. Her genetic power was the ability to create doppelgängers of herself. She was portrayed by Monica May.

Sydney "Syd" Drew

The S.P.D Pink Ranger. Born into a rich family and grew up with a privileged life. Her genetic power was the ability to make her fist into an object that she handled. She was 

portrayed by Alycia Purrott.

Omega Ranger (Sam)

Sam was a child in the year 2025 who had befriended the S.P.D. Rangers. In the year 2040, he became the S.P.D. Omega Ranger, and was sent into the past to prevent a tragedy from creating his own future. However, as a result of the time travel, he could only exist either as an orb of energy or morphed as the Omega Ranger. He was portrayed in suit and voiced by Brett Stewart.

Commander Anubis "Doggie" Cruger

The commander of S.P.D.'s Earth Branch, he also holds the title of the S.P.D. Shadow Ranger. He is a Sirian, an alien species resembling humanoid reptilian dogs. He is in S.P.D. because he is trying to find his wife, Isinia, who was abducted by one of Emperor Grumm's underlings. He was portrayed in suit and in voice by John Tui.

Doctor Katherine "Kat" Manx

S.P.D. Earth Branch's lead scientific researcher; she is the one that develops the Ranger technology, and led a research team that inadvertently created the B-Squad Rangers and their genetic powers. She is of an alien race that resembles earth cats, as her name suggests. When she was faced with a situation that required action over talk, she activated a 1-hour temporary SPD Morpher and became the S.P.D. Kat Ranger. She was portrayed by Michelle Langstone.

Nova Ranger

Sam's ally and fellow Ranger in the year 2040. She was also portrayed in suit and voiced by Antonia Prebble. She appeared only in the last episode of the SPD series.