The satellite itself was essentially nothing more than a Stargate attached to a hyperdrive; the satellite was equipped with only the most minimal equipment and just enough power for it to arrive at a destination and protect itself. (SGA: "First Strike")
On its own, the satellite was not dangerous; it was only after the Stargate was activated that its true purpose as the medium for one of the most powerful and efficient energy weapons thus far encountered by the Tau'ri, was revealed. This allowed for a large power source (Zero Point Modules) to create a sustained and fixed energy beam which could be sent through a host Stargate from a stationary emitter. Once the beam reintegrated through the satellite's Stargate, the beam could be redirected in any direction. The sheer force generated by the beam not only carried enough power to sustain the satellite's shields, but also allowed the wormhole to remain open so long as substantial power was channeled into it; since the Asurans had an unlimited number of ZPMs they could sustain the beam indefinitely. The weapon also had the added benefit that its victims could not use their own Stargate for escape, due to the proximity of the satellite's active gate. (SGA: "First Strike")
In response to the destruction of much of their fleet, the Asurans sent the satellite to Lantea as a means of ending the efforts of the Atlantis expedition once and for all. When the satellite arrived in Lantea's orbit the Apollo was sent to investigate. Once close enough to the satellite the Apollo was able to discern a Stargate, which activated and directed its beam at the ship. While the ship's Asgard shield struggled to hold back the beam, the satellite swung towards the planet and directed the beam to Atlantis. The city managed to raise its shield in time to block the attack, and deduced that the beam would continue to fire as long as power was available. In order to relieve the pressure off of the shield the Atlantis expedition submerged the city, only to discover that the satellite's beam was much more efficient at penetrating the water than was hoped.
Realizing that there was nowhere on the planet safe from the satellite, the Atlantis expedition decided to activate the city's Stardrive for the first time in millions of years. The city's sole Zero Point Module did not have enough power to fire the Stardrive on its own, however, so they utilized the recently discovered Mobile drilling platform to provide more power. Still lacking the necessary energy due to the strain on the shield, a squadron of F-302 fighter-interceptors hurled an asteroid in front of the satellite, which was dense enough to intercept the beam; the city's shield was lowered, which provided just enough power for the stardrive to achieve escape velocity. Unfortunately, the beam then cut through the asteroid and grazed the city as its shield was being raised again, causing Atlantis to drop out of hyperspace prematurely due to the damage caused by the beam. Whether the satellite is still in Lantea's orbit or was recalled to the Asuran homeworld is currently unknown. (SGA: "First Strike")