SpaceX has announced that during its next flight of the Falcon 9 rocket, it will attempt a precision landing of the first stage of the rocket on a special platform floating at sea. SpaceX calls that platform the autonomous spaceport drone ship. Previously SpaceX has used soft water landings to allow it to recover the first stage of the rocket.
Landing the stage on a platform floating in the ocean will be more challenging than the soft water landings that have occurred before. SpaceX admits that the odds of success are 50% at best. While admitting that there is a great chance for failure, SpaceX notes that this is the first in a series of tests that will deliver fully reusable Falcon 9 first stage rockets in the future.
The Falcon 9 first stage is a massive vehicle standing 14 stories tall and traveling at speeds up to 100m/s. To help stabilize the stage during reentry, SpaceX ignites the rocket engines in a series of three burns with the first burn adjusting the impact point of the rocket. The next burn helps to slow the stage from 1300 m/s to 250 m/s.
The final burn that is performed is the landing burn when the landing legs deploy and speed is reduced further to 2 m/s. The landing pad form the rocket is 300 x 1000 feet. Previous landing attempts offered accuracy of around 10km and this time out SpaceX is going for an accuracy of 10 meters. One key upgrade to help with accuracy is the attachment of four hypersonic grid fins in an x-wing configuration. The fins move independently for roll, pitch, and yaw control.