There could be different galaxies with their own laws and Police Forces in Space. The Frontier regions could be mostly Lawless and Filled with Bounty Hunters, what Law exists here is mostly verifying captures and handing out payment for Bounties. 

Unknown Sectors like Earth and the Milky Way would be uncontrolled and Lawless. 

A Star Fleet esque group could exist that are mostly concerned about being explorers but still have offensive capabilities.  

I think perhaps Subspace would be the most viable form of transit and communications. With some form of Combat Hard-Suits from Mass Effect. 

Combat hard-suits use a dual-layer system to protect the wearer. The inner layer consists of fabric armor with kinetic padding. Areas that don't need to be flexible, such as the chest or shins, are reinforced with sheets of lightweight ablative ceramic.
The outer layer consists of automatically-generated kinetic barriers. Objects traveling above a certain speed will trigger the barrier's reflex system and be deflected, provided there is enough energy left in the shield's power cell.

Armored hard-suits are sealable to protect the wearer from extremes of temperature and atmosphere. Standard equipment includes an onboard mini-frame and a communications, navigation, and sensing suite. The mini-frame is designed to accept and display data from a weapon's smart targeting system to make it easier to locate and eliminate enemies.