If we left the gange behind, who’s riding shotgun?
We could name a horse “shotgun”... ;-)
For all orbital maneuvers, our Gas-Cooled Nuclear Reactor/Rocket Engines are fully manned by accredited pilots in the event that emergency contingencies require their operation. Emergency evacuation is always a last-ditch possibility, and the Shuttles are our life-boats.
Additionally, the shuttles, being used for asteroid survey operations, have assay LASERs in the nose of the craft. An emergency operation could include the dire necessity of using those devices which were designed entirely for peaceful purposes in a defensive manner.
Now, admittedly, some of our pilots are a bit on the young side, since we consider enthusiasm to be one of the most important qualifications, and we scoff at the notion of child-labor laws. If we didn't make our kids work, they'd be utterly useless, like most of the ones we left behind.
So essentially, to answer the question, "Who’s riding shotgun?", I have to admit that for the most part ...
... it's teenagers.