Code                 Result
  
one million dollars  5000 more credits   
quickening           God mode   
come get some        Full Ammunition   
dilithium            Full energy   
there is no spoon    Return to Starbase to complete mission  
boom stick           All items    
ragtag               All ships   
kessel run           Ship enhanced
say ahh              Open a closed gate/warm hole

Hints

Hidden Cargo:
While on a mission or just touring the galaxy; be on the lookout for space debris. There is all kinds of space junk floating around out there. But specific free-floating crates can help fill your credit account if you know where to take them. Your ship's radar will not detect crates as long as your distance is within 8.0 or so.

Lost Atrwork:
There is a crate of lost artwork in the top dome of Dr. Cassitor's Main Station. One of the ways to access it is when you are going to deliver the beacon of the Demon Pirates. The easy way to understand the location is, when facing the correct direction towards the landing pads, just fly up, towards the dome. It'll show up on radar, just fly towards the middle of the dome. You'll see it.

Expensive Space Debris:
There is a crate filled with 1000 credits sitting between the station and an asteroid field that is directly below it (the bottom of the station is the side without the docking pad) in the Draconis Ripstar Field.

Infinite Afterburnurs (also works in Demo version):
Use the afterburners to accelerate to full speed, then qickly hold "Q" (slide button). If done correctly your ship will maintain its current speed and direction until the key is released. This uses no afterburner energy.

Here is a list of all the essential space junk and where you need to take it:

Space Junk       Who Wants it
Trade Goods      New Zurich Orbital in the Earth Sector 
Spare Parts      Drake Station in the Inustrial Sector of the Hub Region
Contraband       Arman Patrioli (to trade w/ Arman you need to first find his missing handguns)
Mining Equipment Apollo Research Station (this is only for Gal Span pilots)
Medical Supplies Mercy Hospital Station
Lost Artworks    Baron Malkar

Thanks to Revolution reader Jake Logan, SimonTheCrow, Thilina and Saliya Pinto, SimonTheCrow and Jack Griffin!