During the war with the Wraith, the Lantean Council ordered the scientists working on Project Arcturus to build an outpost and conduct research on the project. Eventually, a Wraith fleet arrived, including a Hive ship, intending to cull the planet.
The Lanteans destroyed the Wraith fleet using their experimental power source and one of their weapons. Unfortunately, Project Arcturus had not been perfected: it began to overload and the weapon ended up destroying not only the orbiting Wraith ships, but leveling every building within range on the planet's surface. The Lanteans eventually managed to shut down both the weapon and the power source, but they were all killed by hard radiation while doing so.
10,000 years later, Dr. Meredith Rodney McKay, Chief Science Officer attempted to perfect Project Arcturus. Unfortunately, the power core overloaded, forcing McKay and Sheppard to flee with the resulting explosion destroying Doranda and 5/6ths of the surrounding solar system. (SGA: "Trinity")