Seed ship

Stargate seeding ships are unmanned spaceships launched from Earth by the Ancients tens of millions of years ago. Before launching the Destiny, the Ancients sent out several of these ships to make a path for the Destiny across the universe. Their mission was to search for suitable planets and plant Stargates on them, which the ships themselves were capable of manufacturing, and then transmit that information back to the Destiny.

Later, the Destiny itself would be sent to these planets to perform more detailed scans. Nothing is known about their appearance.

A short time after arriving on Destiny, Dr. Nicholas Rush managed to gain access to the subspace link that these ships use to communicate with Destiny, and had begun to sift through the data, looking for anything of interest.

Behind the scenes
Joseph Mallozzi on his blog stated that it was safe to assume that the automated ships replenished their capacitors in the same manner as Destiny itself namely by plunging into stars. Furthermore, he said that it made sense that the gate seeding ships possessed the capacity to source material from the worlds they passed.