What Power Outage? 20
Completed Chapter 4, Episode 5 of Spartan Ops without losing a generator on Heroic or harder.
Infinity Multiplayer :: Spartan Ops related. Online Required. Must be obtained on Heroic+.
Don't lose a generator during Episode 5 'Memento Mori', Chapter 4 'The Cauldron Base' either Solo or Cooperatively.
Best to do Co-op with 4 players. There are 2 generators you must protect. A good method is to use both Warthogs (or the Mantis) that are at the start of the level. Use them to kill the enemies up until you reach the generators.
Position both Warthogs between or around each generator to protect the one that will be attacked (the side the covenant is dropped off on, that generator is usually attacked). There are also stationary turrets located above each generator if you need extra firepower.
Repeat if unsuccessful.
DON'T do this with 4! Do with only one more person. You'll have Mantis instead of warthogs and it will be incredibly easy.