Derelicts 

derelicttype is:

For planets
----------------
AngelMoon
AngelMoon_clean
Homeworld
PlanetOfOrigin; 
PlanetOfOrigin_scarred

For crates
----------------
Crate

For odd ships
----------------
Ghostship
PrisonShipNew
PrisonShipOld
LifeBoat
Shipwreck

For the Scaffold
----------------
Scaffold
Scaffold_scarred
ScaffoldFingerA_scarred
ScaffoldFingerB_scarred

For space junk
----------------
Junk0_antenna
Junk0_fin1
Junk0_fin2
Junk0_GunAmmo
Junk0_LGun
Junk0_panel
Junk0_sensors
Junk0_SGun
Junk1_partA
Junk1_partB
unk1_shell
Junk1_strut
Junk2_panelA
Junk2_panelB
Junk2_panelC
Junk2_panelD
Junk2_shipwreck
FragmentPanel0a
FragmentPanel0b
FragmentPanel0c
FragmentPanel1
FragmentPanel2
FragmentPanel3
FragmentStrut
Junk2_Boiler			(causes mission to crash if used)
Junk2_BoilerCasing		(causes mission to crash if used)

 - Note; while you need to add the line 'IncludeDerelict    <derelicttype>' in the level file for all the above listed derelicts, you can get away with it and forget about these lines as far as the smaller planets are concerned. You do need to have a line in the level file including the Homeworld if you decide to use that however. Homeworld planet is HUGE, and I would suggest placing it way, way out of your map; try a value of 3000000 for the x (or the y, or even the z) position to start you off.
