It is known that the Arctic Base was one of Herobrine's haunts, as he successfully caused the crew of the Arctic Base to 'disappear', all but Grayson. After Drake and Armen had arrived, Herobrine attacked the base and they fled. They watched it explode after a missle from Herobrine's base nearby hit it. A ruin was found nearby, and inside they found a portal which they opened using a book found in a 'chest made of crystals'. This portal led to the Badlands, which is now believed to be the same world, just so far into the future that technology barely exists.
The people known to have worked in the Arctic Base are as follows: Grayson, Collin (mentioned by Grayson) Jacob (mentioned by Grayson in The Haunting 3 Herobrine Sighting) and Luke (name on a door).