An orbital is a large, immobile ship, typically with heavy DP, a fair number of guns, scanners, or racks, and no engines at all.  Orbitals are used for defending owned worlds and confer some special benefits to friendly ships at those worlds.  
 

• Orbitals always repair damage during the Auto Repair II phase, even if they have fired their guns or received damage.
• You can repair damage to orbitals for a cost of 3 DP for 1 RU during the Repair phase (instead of the usual 2 DP for 1 RU cost).
• Orbitals fully repair any friendly or allied ships that are loaded or boarded during the Repair phase.

 
 
A starbase is a special type of orbital that each empire possesses at its homeworld at the start of the game.  In addition to the standard orbital benefits, starbases provide these additional benefits:
 

• A starbase prevents all devices from functioning within the same sector.
• A starbase negates all ion storm damage to all ships, friendly or not, in its sector.
• Any ship in the same sector as a friendly or allied starbase always repairs damage during the Auto Repair II phase, even if those ships have fired, moved, or received damage.
• A starbase cannot be self-destructed, nor can it be destroyed by self-destructing cargo aboard it.

 
Basic configuration:
 

• Guns: 30 (starbase 150)
• DP: 40 (starbase 200)
• Engines: 0 (maximum 0)
• Scan: 1 (starbase 2)
• Racks: 2 (starbase 8)
• Tonnage: 20 (starbase 999)
• Cost: 25 (starbase n/a)

 
 
 
Additional component cost:

• Guns: exp(guns/10)
• DP: exp(DP/15)
• Engines: n/a
• Scan: exp(scan/2)
• Racks: exp(racks/3)

 
 
Additional component tonnage:

• Guns: exp(guns/10)
• DP: exp(DP/20)
• Engines: n/a
• Scan: exp(scan/5)
• Racks: exp(racks/2)