Blind Sally posted:

The game timeline mentions at least one other colony planet (Gyre in the Altair system). If I were to seriously try and guess what made Helghan a chokepoint planet, it probably go something like this:

Though powerful, human space crusiers probably aren't advanced enough to handle sustained and uninterrupted spaceflight past certain distances. That the Helghast have a space chokepoint is probably because ships don't have the range to continue onto other colonies without first stopping to refuel on Helghan.