Updated: May 22, 2020
BEHIND THE SCENES (THE CHALLENGE)
Lost in Space "The Challenge" (Season One March 2, 1966 )
The Robinson party meets Quano, a stoic twelve-year-old alien boy from a warrior race who's on the planet for a survival challenge. Since Will is near his age, a fight-challenge is offered. Will has no interest in fighting without reason, but Quano wants the challenge, in part to prove his superiority but also to prove his worthiness as heir apparent to his often-absent father, ruler of their male-dominated race. Quano finally goats Will into accepting, but Will doesn't know that, if he wins, Quano's family with have to destroy him and all witnesses. Dr. Smith surreptitiously learns of this and, threatened into silence, works to wear Will down with over-training before the contest, to save their lives.
While both Will and Quano are said to be twelve years old, at the time of the initial airing of this episode Bill Mumy had just turned twelve, but Kurt Russell was fourteen and would turn fifteen two weeks later. Kurt is obviously significantly larger than Bill.
At the beginning of the episode Will and Dr. Smith are monitoring an intruder alert system, but in earlier episodes it is shown that the Jupiter-2 has a force field that can be deployed meaning that the intruder alert system would have been unnecessary.
Quano: [to Will] You do the work of WOMEN! You should be ashamed!