Falcon 9 First Stage lands on drone ship

During my ongoing literature review I often discover interesting facts about things I’ve never thought about. Sometimes I can connect these facts with my own observations: The result is mostly a completely new idea why things are as they are. Maybe these ideas are new to you, too. Therefore I’ll share my new science based knowledge with you!

This week: This time, I think about the first successful landing of a Falcon 9 first stage at sea.

On Friday, April 8th, SpaceX managed to land the first stage of their Falcon 9 rocket on top of a floating landing platform in the Atlantic Ocean. This achievement marks another milestone of SpaceX on their way to reduce the rocket launch costs by making the first stage of their rockets reusable. It was SpaceX’s fifth attempt to recover a spent first stage on an ocean-going barge. The first four tries were unsuccessful and resulted in the rocket coming down too fast or tipping over after landing.

The Falcon 9 rocket launched from Cape Canaveral at 2043:31 GMT with a Dragon cargo capsule transporting 3.5 tons of cargo to the International Space Station. After the first stage completed its job and seperated from the Flacon 9 upper stage that continued to accellerate the Dragon capsule to orbital velocity, it executed three rocket burns to land on the floating landing platform named ‚Of Course I Still Love You‘.

The first burn slowed down the rocket and established a trajectory towards the ship. In order to survive the reentry into the atmosphere, the rocket used its engines again to slow down its velocity. The first two burns were executed with three of the nine engines and the last burn, which was the landing burn, was executed with only one engine. About 8 minutes, 35 seconds after lift-off, the first staged successfully touched down on the deck of ‚Of Course I Still Love You‘.

The landing occured under difficult conditions as periodic waves tilted the barge, which precisely hold its position with underwater engines, by 2 to 3 degrees. In addition, the first stage had to deal with stiff winds during the final approach.

Being able to successfully land the spent first stage at sea is an important achievement as, due to the first stage’s fuel margins, the rocket can not always return to the shore after lift-off and thus a mobile landing platform is necessary to make the booster reusable under any launch profile.

The recovery crew planned to weld steel shoes over the booster’s four landing legs to ensure that it will not tip over and can safely return to Port Canaveral. After being inspected, the rocket will fire its engines 10 times in a row on the ground in order to qualify for a second flight into space. If things go well, this first stage could fly again this year.

Well done, SpaceX!