Last night, starting at 9pm GMT, Bungie made a new mission available to those enjoying the Destiny beta. The mission took players to the Moon for an outing to the Temple of Crota. It was the sixth story mission to feature in the beta, and it was called The Dark Beyond.
The reason behind the temporary content was because the studio was aiming to attract as many concurrent players as possible so they could stress test the servers ahead of September's launch. According to this Tweet, any player who tackled that mission, or did any activity at that time, will have earned an Emblem to use in the final game.