During the early years of the program, SpaceX attempted to catch the descending payload fairings, under parachute, in a very large net on a moving ship in the Atlantic Ocean east of the Space Coast of Florida.

Tree, formerly known as Mr. Steven,[4] and its sister ship, Ms. Chief—were chartered by SpaceX and used 2018–2021[5] as experimental platforms for recovery of rocket fairings from Falcon 9 orbital launch trajectories.

In May 2021, SpaceX purchased and began converting two offshore supply ships named Ella G and Ingrid for towing and supporting droneships as well as fairing recovery operations on the east coast.

[14] The vessel subsequently was chartered by SpaceX in 2018 for an experimental program to provide surface marine "catch and recovery" operations for a test program attempting to bring the large 5.2 by 13.2 meters (17 ft × 43 ft)[15] Falcon 9 launch vehicle satellite fairings—separated at high speed and high altitude—through atmospheric reentry and parachute descent to the ocean surface in a controlled way, and then recover them for evaluation and potential reuse.

[19] In June 2019, Mr. Steven was renamed Ms. Tree (a play on the word mystery), after being purchased by Guice Offshore (GO), a company with a long-standing contractual relationship to SpaceX as a provider of a variety of marine services.

[4][20] On June 25, 2019, SpaceX successfully caught its first fairing half on Ms. Tree in the Atlantic Ocean off the Florida coast as part of the Falcon Heavy STP-2 mission.

[23] Although a dry recovery is preferable to maintain a cleaner environment inside the fairing to protect future payloads, eventually SpaceX would drop it as a requirement.

Ms. Chief was outfitted with a matching set of four wide arms and a catch net by October 2019, in preparation for dual simultaneous fairing recovery attempts.

[30] SpaceX abandoned the experimental program to recover descending-under-parachute payload fairings dry, in a net on a fast ship, by April 2021.

[16] The "bouncy castle" idea led to SpaceX contracting for the fast vessel Mr. Steven which was subsequently modified to facilitate a large net being strung between long arms that extend considerably beyond the width of the ship.

Mr. Steven was equipped with a dynamic positioning system and was first tested after the launch of the Paz satellite from Vandenberg Air Force Base in February 2018.

[35][36] The test was not fully successful because the fairing missed the boat by a few hundred meters but landed safely in the water[37] before being recovered and taken back to port.

[38][39] In October 2018, to practice recovery outside mission situations, SpaceX performed drop tests of a fairing half from a helicopter with Mr. Steven below.