10 years ago
From the USMCs point of view, the whole mission was a baby-sitting job. Lost contact with a distant colony, so what. Probably the only problem is a broken comm transceiver.
A former traumatized warrant officer claims that there are "Aliens" on this colony- suuure, it's an invasion from outer space. Why to waste money and personnel for an unconfirmed, non-believable threat? But they HAD to intervent somehow, the safety of the colonies belonged to their area of responsibility. They couldn't simply ignore the problems on LV426, but to limit the outlay they sent an as small as possible squad.
Probably WY recommended a small squad too- enough marines for a scouting party, but not enough to pose a real threat to a WY cleanup-crew.
And i guess WY wanted all non-company witnesses silenced if the alien infestation is confirmed for sure.