A few hours ago the SpaceX Dragon spacecraft ended its CRS-15 (Cargo Resupply Service 15) mission for NASA splashing down smoothly in the Pacific Ocean a little more than 420 kilometers (about 326 miles) off the coast of California. The Dragon left the International Space Station a few hours before.
Shortly after landing, SpaceX’s 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 2, 2018.
The Dragon spacecraft brought back to Earth more than 1,700 kg (a little more than 3,800 lbs) of mixed cargo between the pressurized and the non-pressurized section that include various scientific experiments and biological samples. The nuce that are part of the Rodent Research-7 experiment to understand how microbes interact with the digestive system in space are brought back to Earth alive. Part of the samples are contained in the freezers because they need to be kept at low temperatures. It’s the case of biological samples such as those of the Micro-11 experiment, which concerns fertility in space, and samples used for a cancer study.
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 next resupply mission for the Dragon cargo spacecraft could begin as early as November 29, 2018, although launch dates are always approximate. For the moment they have to verify that samples and experiments returned to Earth undamaged.
Conducting a SpaceX resupply Mission with a partially used Dragon spacecraft launched on a rocket with a used first stage is becoming normal. The next mission will begin with a rocket launch with the new version of the first stage called “Block 5”, designed to optimize its reusability, so whether a new or a used first stage is used will become less and less important.