P9Q-281 is a planet in the Milky Way galaxy which held a Stargate. This planet is one of the planets that was inputted into the computer after the first time Colonel Jack O'Neill used the Ancient Repository of knowledge.
When they first send the probe through they find a stool with Ancient Writing on it. The probe came through when the first sun was in the sky so it did not record that the planet can get 200 degrees Fahrenheit.
Captain Samantha Carter and Teal'c, along with a team went to this world in order to help O'Neill after the Ancients' repository of knowledge modified his brain. The Dial Home Device was stuck in a state of mid-dial and was unusable. The planet had two suns and the heat would have killed them if Jack had not written up a schematic of the DHD and instructions on how to fix it which enabled the team to get back to Earth. (SG1: "The Fifth Race")