SpaceX’s robotic Dragon capsule brought tons of cargo back down to Earth from the International Space Station today, in a trip that ended with a Pacific Ocean splashdown.

The trip began early today when astronauts used the station’s robotic arm to pull the Dragon away from its port and position it for the automated descent.

Over the past few weeks, the crew unloaded about 5,500 pounds of scientific experiments and supplies from the capsule, which arrived nearly a month ago, and loaded it back up with research samples and other cargo destined for return.

The payloads added up to almost as much mass as the Dragon brought up.

French astronaut Thomas Pesquet documented the Dragon’s departure in a series of tweets:

Today we said good bye to #Dragon! She is taking part of us back to ground with her – important scientific samples, some from the crew! pic.twitter.com/faJUMrmDf1 — Thomas Pesquet (@Thom_astro) March 19, 2017

It has become somewhat of a tradition with all the visiting vehicles recently: please bear with us for the requisite selfie ;) pic.twitter.com/3IIvopS4Ee — Thomas Pesquet (@Thom_astro) March 19, 2017

Dragon waiting to be released, above the dunes of Namibia Le #Dragon prêt à être relâché, au-dessus des dunes de Namibie pic.twitter.com/z2bkIBPokS — Thomas Pesquet (@Thom_astro) March 19, 2017

#Dragon and #Soyuz facing each other on the @Space_Station. Different technology, different language, same goal – return to Earth! pic.twitter.com/lSK7hFRBbP — Thomas Pesquet (@Thom_astro) March 19, 2017

Quelques minutes après sa relâche, le #Dragon redevient livré à lui-même, prêt à affronter une rentrée atmosphérique flamboyante ? pic.twitter.com/7Ja5v9cNSx — Thomas Pesquet (@Thom_astro) March 19, 2017

At a distance of 150 m in the dark, this is all we can see from the #Dragon: navigation lights reflecting on the solar array wings pic.twitter.com/i0aZ9ycTrb — Thomas Pesquet (@Thom_astro) March 19, 2017

Gear destined for disposal was packed in the Dragon’s unpressurized trunk, which was jettisoned to burn up during atmospheric re-entry.

The discarded hardware included the OPALS device, which was used to test high-speed laser communications between Earth and space; the MISSE radiation-tolerance experiment; and apparatus for testing robotic refueling procedures.

The Dragon’s pressurized capsule weathered re-entry temperatures ranging up to 3,000 degrees Fahrenheit, then unfurled its parachutes for the splashdown about 250 miles west of Baja California.

Recovery teams headed out to pick up the capsule and bring it to shore at Long Beach, Calif. High-priority payloads will be unloaded and delivered to NASA there. Then the Dragon will be transported to SpaceX’s facilities in Texas for post-flight processing.

Dragon is headed to port for a cargo handover to @NASA. https://t.co/C3Pix9DGAg pic.twitter.com/wPdFTlsNsP — SpaceX (@SpaceX) March 19, 2017

The Dragon’s cargo includes stem cell samples as well as tissue samples from experiments aimed at tracking how the body heals itself in zero-G. NASA says the experiments could provide new clues for treating cancer and improving the healing process.

This was the 10th SpaceX cargo resupply flight carried out under the terms of a multibillion-dollar cargo contract with NASA. Orbital ATK is getting ready for yet another cargo delivery flight, which is due for launch no earlier than March 27 from Florida. The Cygnus cargo craft for that mission has been dubbed the S.S. John Glenn, in honor of the space pioneer who passed away last December.