After a successful SpaceX launch earlier this week, the Dragon spacecraft has arrived at the International Space Station. The cargo capsule made contact with the ISS on Wednesday morning.

NASA astronauts Jeff Williams and Kate Rubins worked to ensure a smooth launch, capturing the Dragon with the station’s massive 57.7-foot robotic arm. They’re still in the process of docking the Dragon and won’t actually open the hatch until Thursday, according to the official ISS Twitter account.

The Dragon contains 5,000 pounds of gear for the ISS crew, including a DNA sequencer. It marks the first time the technology will be used in space. The sequencer can be used to study the astronauts’ health and test the station’s water recycling system. It may even help identify a mysterious mold that’s been growing on the walls of the ISS.

The SpaceX capsule also holds one of two special docking adapters that will allow commercial spacecraft to deliver human astronauts to the ISS in the future. The first docking adapter was destroyed in a SpaceX launch accident last year. NASA and Boeing are currently working on a replacement, which should be ready for delivery in another year-and-a-half.