California: After a nine-month ordeal in the space, the Dragon spacecraft successfully splashed down off Florida coast, bringing NASA astronaut Sunita Williams along with Crew-9 members Butch Wilmore, Nick Hague, and Russian cosmonaut Aleksandr Gorbunov safely to Earth. Now, have you ever wondered why the NASA astronauts opted for splashdown instead of landing on solid ground? Check what science says about splashdown and landing on the ground.
What is splashdown and how it works?
Splashdown is a process of landing a spacecraft in a body of water, mostly seas and oceans, especially by a parachute. The same process was used by American manned spacecraft prior to the Space Shuttle program. This process is also possible for the Russian Soyuz spacecraft and Chinese Shenzhou spacecraft to land in water, though this is only a contingency.
Before returning to Earth, a spacecraft generally performs a safe landing and for this, it needs to slow down. While returning to planet earth from space, a spacecraft generally releases a lot of kinetic energy and the friction with the atmosphere introduces drag, which actually helps in slowing down the spacecraft. This friction later changes the spacecraft’s kinetic energy to thermal energy, or heat.
The heat later radiates out into the surrounding air, which gets hot and in the case of SpaceX’s massive Starship rocket, this temperature even reaches 3,000 degrees Fahrenheit.
But no matter how quickly this transfer of energy happens, there’s still not enough time during reentry for the vehicle to slow down for a safe landing. So, the engineers have opted for other methods that can slow down a spacecraft during splashdown.
The spacecraft needs to land somewhere so that it can control that heat and energy. And for this, the scientists found out early that only water can make an excellent shock absorber. Thus, the idea of splashdown was created.
Why Dragon spacecraft landed on water?
The Dragon spacecraft was allowed to land on water as it is an ideal landing surface for spacecraft due to its low viscosity, which allows it to deform quickly under stress, and its low density compared to solid rock. Apart from this, since water covers 70% of Earth's surface, the likelihood of landing in it when returning from space is high.
What are advantages of splashdown?
It helps in soft landing: With the large area of the ocean, the spacecraft gets a relatively safe area to land and water also works like a cushion while it simultaneously decreases the risk of damage to the vehicle.
Easy platform for landing: Water works like an easily accessible platform to undertake spacecraft landings. When space technology was not so developed, the vast ocean provided enough space to land, which became extremely advantageous for spacecraft which lacked precision landing capabilities.