A few hours ago the SpaceX Dragon spacecraft ended its CRS-18 (Cargo Resupply Service 18) mission for NASA splashing down smoothly in the Pacific Ocean almost 500 kilometers (about 300 miles) off the coast of California. The Dragon left the International Space Station a few hours earlier.
Shortly after landing, SpaceX boats went to retrieve the Dragon to transport it to the coast. The cargo brought back to Earth will be delivered to NASA soon, probably tomorrow. The Dragon spacecraft reached the International Space Station on July 27, 2019.
The Dragon spacecraft brought back to Earth more than 1,200 kg (aabout 2,700 lbs) of mixed cargo between the pressurized and the non-pressurized section that include various scientific experiments and biological samples. Part of the samples are contained in the freezers because they need to be kept at low temperatures.
SpaceX is the only American company that has a spacecraft that can bring intact cargo back to Earth so the Dragon missions are really important for NASA. Samples produced during many of the experiments conducted on the International Space Station may require in-depth analyzes possible only in specialized laboratories on Earth.
Medical research, other biological research and experiments of other types are conducted on the Station. When they need to bring something back to Earth a little cargo can be transported together with the astronauts on the Soyuz spacecraft but their total volume requires a cargo spacecraft that can bring them back to Earth.
The Dragon cargo spacecraft brought back to Earth biological experiments such as Biorock, which investigates the interaction of microorganisms with liquids and rocks, Space Moss, about the growth of mosses in microgravity. There’s also the Goodyear Tire investigation which aims to improve the materials to produce tires. Along with many other experiments that include medical ones such as the Amyloid Aggregation on Alzheimer’s, they exploit the International Space Station’s microgravity to obtain results that are impossible in the Earth’s gravity.
The next resupply mission for the Dragon cargo spacecraft could begin as early as December 2019, although launch dates are always approximate. For the moment they have to verify that samples and experiments returned to Earth undamaged.