SpaceX’s Dragon cargo spacecraft has been hanging out at the International Space Station for around a month now after delivering supplies and various other goods to the astronauts in early December. Missions to resupply the ISS happen on a regular basis, but as its time in space comes to a close, the cargo craft has one more very important task to carry out.

NASA announced that on Thursday, December 10th, the robotic arm of the space station will release the Dragon for return to Earth, with some very precious tucked away inside.

As NASA explains in a new blog post, astronauts of Expedition 58 — the current ISS mission — have been loading “time-critical space experiments” in the Dragon’s cargo hold, and scientists on the ground are eager to get their hands on them.

The spacecraft will be fully disconnected from the space station today, severing the power supply and removing the connection between the cargo craft and the ISS module on which it is installed. The space station’s robotic arm will hold it in place and prepare for its release which is expected to happen early on Thursday morning.

“After its departure, Dragon will orbit Earth a few more hours before splashing down in the Pacific Ocean off the coast of southern California,” NASA explains. “SpaceX personnel will retrieve Dragon and return it to port where NASA engineers will extract the precious cargo for immediate shipment to investigators around the country.”

Some of the science being conducted on the ISS recently includes research into stem cells as well as how the human brain might be affected by low gravity. The team will send back “biological samples” that were collected aboard the space station as well as various other completed experiments that the crew has wrapped up since the Dragon arrived.