SpaceX has successfully completed its 19th commercial resupply (CRS) mission for the International Space Station, with the Dragon cargo spacecraft used for the mission splashing down in the Pacific Ocean early this morning. The Dragon used this time around has also actually made this round trip twice before on previous SpaceX CRS missions.
The Dragon launched for CRS-19 on December 5, and attached to the Space Station on December 8. It spent around a month docked at the ISS, while astronauts unloaded its contents, including around 5,700 lbs of supplies and experiments. Dragon returned with ample cargo, as well, including scientific investigations that will be studied by researchers here on Earth, continuing the orbital experimentation work of the astronauts on board the Station.
These include tiny aquatic animals called "rotifers," as well as mice, both of which were being used to study the effects of microgravity on different life forms. Another experiment aimed to help scientists develop solutions for the radiation exposure astronauts will endure during long-duration spaceflight. That's just a small sample, and at any give time there are as many as hundreds of active ongoing experiments from academic institutions, NASA itself and private partners.
From here, the Dragon will be recovered from the Pacific and its contents will be recovered once it's ferried back to dry land. SpaceX has another resupply mission on the books coming up in early March, and continues to make progress on its mission to certify Crew Dragon for human spaceflight to the ISS, too.