Space shuttle Discovery is on its way home.

Discovery undocked from the International Space Station on Saturday morning. The shuttle and its seven astronauts spent one-and-a-half weeks at the orbiting outpost, giving it a new ammonia tank and other supplies. They’re set to return to Earth on Monday.

Before leaving, shuttle commander Alan Poindexter thanked the six station residents for their “utmost hospitality.” The station’s skipper, Oleg Kotov, said it was “really, really sad” to see them go.

It may be a long time before so many people are together again in space. Only three shuttle flights remain, each with a crew of six. That’s one less person than usual, and will result in 12 people orbiting together, instead of 13.