It works on the Pokeball principle. Actually the entire idea can about when Ash got a little too "into" his Pokemon and decided to design a Pokeball that he could use to consumate his relationship with Ekans. The Galactic Federation found out about it and bought his prototype and reconfigured it for use on Super Soldiers. After a wild night of passion with Master Chief and Commander Sheppard, Samus found their units (after losing two of their units in her) and stole them for her bounty hunting missions.
And now you know the rest of the story