Takaya Noriko
In 2015 Noriko's father (Captain of the Luxion spaceship) is killed when alien forces ambush his ship in the Milky Way. Seven years later driven by her father's death Noriko joins the Okinawa School for Girls in order to learn how to become a pilot.

Soon after joining the school and with direction from Coach Ota Noriko would go on to rise from the bottom of her class and become the pilot of Earth's most powerful weapon, Gunbuster.

Amano Kazumi
Often referred to as Big Sister, Kazumi is Gunbuster's co-pilot
and fights alongside Noriko against the alien invaders.

She fell in love with Coach Ota as the series progressed, despite
her not agreeing with his harsh training of Noriko. After defeating the invaders with Gunbuster in their first encounter she returns to Earth and finally is finally able to share her true feeling with Coach Ota.

Jung Freud
She is a hot-headed pilot, whose skills put her at top of her robot piloting class. In many ways her skills are equal to those of
Kasumi, however her temperament keeps her from achieving her
true potential.

She is often jealous of the amount of time Coach Ota spends training Noriko, despite this she becomes good friends with
Noriko.

Ota Kooichiroo
Often referred to as simply "Coach", Ota is in charge of the
Exelion's RX Robot Team. He trains Noriko and encourages her to do her best as a pilot, which eventually leads to her becoming Gunbuster's pilot

Coach is also one of the few survivors of the Luxion incident (in which Noriko's father loses his life).

The Alien Invaders
They are insect like in their appearance. Have a short life span and can reproduce in large quantities. Can also attack while in sub-warp, which was thought to be impossible.

It seems that they want to exterminate the human race.

RX-7 Machine
A general purpose space defense weapon.

While being a powerful weapon it doesn't have the power
necessary to fight the alien invaders.

Gunbuster
Earth's ultimate weapon and the only force powerful enough to
stop the invaders. It is composed of two separate units, Buster Machine 1 (Pilot: Noriko) and Buster Machine 2 (Pilot: Kazumi). Gunbuster is piloted by Noriko in spherical cockpit while Kazumi maintains all navigation functions in a different section of the giant robot.

Gunbuster's weapon/defense systems include:
Buster Beam
Buster Colliders
Homing Laser
Buster Missiles
Buster Shield
Inertia Canceler
Buster Tomahawk (Mentioned in 1st radio drama )
Buster Home Run (Mentioned in 1st radio drama)