A few hours ago the SpaceX Dragon spacecraft ended its CRS-21 (Cargo Resupply Service 21) mission for NASA splashing down smoothly in Gulf of Mexico, off the coast of Florida. The Dragon left the International Space Station last Tuesday. For SpaceX, this was the first mission of the second contract with NASA to transport resupplies to the Station with the new version of the Dragon cargo spacecraft, the first to splash down near the East coast of the USA instead of the Pacific Ocean.
Shortly after splashing down, SpaceX boats went to retrieve the Dragon to transport it to the coast. The cargo brought back to Earth will be delivered to NASA within a few hours. The Dragon spacecraft reached the International Space Station on December 7, 2020.
The Dragon spacecraft brought back to Earth about 2,000 kg (more than 4,000 lbs) of mixed cargo 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. The new version of the Dragon space freighter has twice the capacity to transport samples to Earth than the first version.
This Dragon space freighter has also brought a particular cargo back to Earth: twelve bottles of Bordeaux wine and a series of grapevine branches after more than a year spent on the International Space Station. They will be tested to evaluate the effects of microgravity and radiation.
SpaceX is the only American company that has a spacecraft capable of bringing 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.
Splashing down off the coast of Florida cuts cargo delivery times to NASA from 48 hours to no more than 9 hours. This greatly reduces the influence of Earth’s gravity on biological samples, helping researchers analyze the effects of the International Space Station’s microgravity.
The next resupply mission for the Dragon cargo spacecraft could begin in May 2021. The dates are always approximate, and the results of the check-up of the Dragon that just came back to Earth will be more important than ever. The new version was designed to reuse its pressurized section up to five times but that’s possible only if it can maintain structural integrity in its missions.