A colonist was one of the human settlers on Uxarieus.
When David Winton and the other the colonists forced the IMC expetion led by Captain Dent off the planet, he, Winton and some of the other colonists escorted them back to thier spaceship. Winton then put him and another colonist on guard outside the main dome in case the IMC men returned and attacked the dome.
Winton was right and the IMC men did return and attack the dome, knocking out the two colonists on guard. He later recovered and took part in the gunfight between the colonists and IMC guards. (TV: Colony in Space)