Skulltaker Halo 2: Sputnik
Skulltaker Halo 2: Sputnik is an achievement in Halo: The Master Chief Collection. It is awarded for collecting the Sputnik skull in Halo 2: Anniversary on Quarantine Zone while playing on Legendary difficulty. The achievement is worth 5 gamerpoints.
This is probably the easiest Skull to obtain next to to the Blind Skull and That's Just Wrong Skull. At the start of the level, look directly behind you for an Elite. Right behind the Elite is a tunnel (hard to miss). Go through the tunnel and continue walking straight until you pass a bridge, which is to your right. Beyond the bridge there is a narrow ledge jutting out of the cliff face ahead. Jump onto this. Hug the wall (there's just enough room for you to walk) until you get to the end of the cliff, and you will see the Sputnik Skull floating in the air.