A little while ago the SpaceX Dragon spacecraft blasted off atop a Falcon 9 rocket from Cape Canaveral in its CRS-16 (Cargo Resupply Service 16) mission, also referred to as SPX-16. After just over ten minutes it separated successfully from the rocket’s last stage and went en route. This is the 16th mission for the Dragon spacecraft to resupply the International Space Station with various cargoes and then return to Earth, again with various cargoes.

The CRS-16 mission continues SpaceX’s reuse policy in collaboration with NASA. The Dragon is the one used for the mission CRS-10, started on February 19, 2017. What changes is the use of a new first stage for the Falcon 9 rocket, due to the fact that in recent months Elon Musk’s company gradually switched to the new version called Block 5. A few minutes after the launch, the first stage was supposed to land on the pad at Cape Canaveral called Landing Zone 1 (LZ-1) but something happened and it splashed down in the Atlantic Ocean off the nearby coast. We got used to controlled landings but the procedure is still far from easy and can fail. Elon Musk published a tweet that shows the images from the point of view of the first stage as it spins and another in which its descent is seen from the coast.

The the Dragon cargo spacecraft’s cargo is almost 2,600 kg (almost 5,700 lbs) between the pressurized and the non pressurized section. There are about 300 kg (about 670 lbs) of food and other supplies for the International Space Station crew but most of the cargo consists of instruments, hardware and various other materials needed to science experiments and research conducted aboard the Station.

Among the most important instruments on board the Dragon there’s the Robotic Refueling Mission-3 (RRM3), the latest version of a technology that’s been in development for several years to resupply spacecraft of cryogenic fuel such as liquid oxygen. This type of technology was initially created to refuel satellites orbiting the Earth but could be useful also for deep space missions where there are various sources of water that can be divided into hydrogen and oxygen to be used as fuel.

The International Space Station has also become a base to deploy CubeSat-class nanosatellites, but they can also be launched from spacecraft during their flight. The new SlingShot system is on board the Dragon but will be installed in the Passive Common Berthing Mechanism (PCBM) of the other American space cargo ship, the Cygnus. The SlingShot system can launch up to 18 nanosatellites and this will happen after the Cygnus departs the Station.

Among the biological experiments there’s the Rodent Research-8 with 40 mice that are transported in a specially constructed habitat called the Rodent Research Transport Assembly and Support Hardware. Their presence is connected to what’s perhaps the most curious reason for a delayed launch: the mice are alive because their reactions will be studied in the microgravity of the International Space Station and this means that in their habitat there’s also food but in a check the crew found mold in some food bars with the need to replace them.

The Dragon Spacecraft is now en route to the International Space Station and everything proceeds normally. The arrival at the Station is scheduled for Saturday: at about 18 UTC the Dragon is scheduled to be captured by the Station’s robotic arm.