AFalcon 9 first-stage booster is a reusable rocketbooster used on theFalcon 9 andFalcon Heavy orbitallaunch vehicles manufactured bySpaceX. The manufacture of first-stage booster constitutes about 60% of the launch price of a single expended Falcon 9^[1] (and three of them over 80% of the launch price of an expended Falcon Heavy), which led SpaceX to develop aprogram dedicated to recovery and reuse of these boosters. After multiple attempts, some as early as 2010, at controlling the re-entry of the first stage after its separation from the second stage, the first successful controlled landing of a first stage occurred on December 22, 2015, on the first flight of theFull Thrust version. Since then, Falcon 9 first-stage boosters have been landed and recovered 523 times out of 536 attempts, includingsynchronized recoveries of the side-boosters of most Falcon Heavy flights.

In total 51 recovered boosters have been refurbished and subsequently flown at least a second time, with a record of 31 launches and landings carried out by a single booster. SpaceX intentionally limited Block 3 and Block 4 boosters to flying only two missions each,^[2][3] but the company indicated in 2018 that they expected the Block 5 versions to achieve at least ten flights, with only minor refurbishment between missions. The ten flight milestone was first achieved by Booster B1051 on the Starlink 27 mission in 2021.^[4] The twenty flight milestone was first achieved by Booster B1062 on the Starlink Group 6-49 mission in 2024. The thirty flight milestone was first achieved by Booster B1067 on the Starlink Group 10-11 mission in 2025.

All boosters in Block 4 and earlier have been retired, expended, or lost. The last flight of a Block 4 booster was in June 2018. Since then all boosters in the active fleet are Block 5.

Booster names are a B followed by a four-digit number. The first Falcon 9 version, v1.0, had boosters B0001 to B0007. All following boosters were numbered sequentially starting at B1001, the number 1 standing for first-stage booster.

SpaceX attempted parachute of the Falcon 9 v1.0 first stage on flights 1 and 2, however on both attempts the boosters disintegrated on re-entry, and the plans were abandoned in favor of propulsive landings. Boosters B0002 (Grasshopper) and B1002 (F9R Dev1) were modified to make short propulsive hops at test sites to demonstrate landing technologies, and were not used on orbital missions. Three boosters successfully made soft ocean touchdowns on orbital flights but were not recovered.

Falcon 9 Full Thrust (version 1.2 / Block 3) was the first version of the Falcon 9 to successfully land. Changes included a larger fuel tank, uprated engines andsupercooled propellant and oxidizer to increase performance. Block 3 and Block 4 are found in this list while the active Block 5 is listed separately. Block 4 was a test version that included new hardware such astitaniumgrid fins later carried over to the current Block 5. Flights of all Falcon 9 rockets up to Block 4 were limited to 2 flights only, with a total of 14 second flights of these variants. The boosters were either retired or expended after that second launch.

Boosters B1023 and B1025 were originally Falcon 9 boosters which were converted to Falcon Heavy side boosters for theFalcon Heavy test flight.

There are three booster types: Falcon 9 (F9), Falcon Heavy core (FH core) boosters, and Falcon Heavy side (FH side) boosters. Falcon 9 and Falcon Heavy side boosters are reconfigurable to each other. A Falcon Heavy core booster is manufactured with structural supports for the side boosters and cannot be converted to Falcon Heavy side booster, although it can be converted to a lower performance Falcon 9 core booster. The interstage mounting hardware was changed after B1056. The newer interstage design features fewer pins holding the interstage on, reducing the amount of work needed to convert a Falcon 9 booster to a Falcon Heavy side booster.^[82]

Block 5 is the latest iteration of the Falcon 9 and Falcon Heavy boosters. Changes include a strongerheat shield, upgraded engines, newcarbon composite sections (landing legs, engine sections,raceways,RCS thrusters and interstage), retractable landing legs, titanium grid fins, and other additions that simplify refurbishment and allow for easier reusability.^{[citation needed]}

Block 5 boosters were initially certified for 10 launches^[83] which was increased to 15. A "deep-dive" examination has been performed onFalcon 9 B1058 and B1060 after their 15th flight,^[84] and SpaceX certified Falcon 9 boosters for 20 missions. SpaceX has further increased the Falcon re-flight certification to 40 flights per booster, since 20 flights of some boosters are reached.^[85][86]

B1058, first launched on May 30, 2020 (Crew Dragon Demo-2), was the only booster with NASA logos. On September 11, 2022, during a Starlink mission, it became the first to complete fourteen launches and landings to become the fleet leader. With another 5 Starlink missions, B1058 achieved 15, 16, 17, 18 & 19 launches and landings, the first to do so.B1062 had been the first to achieve 20th, 21st, 22nd & 23rd launches and landings of a booster.Guinness World Records holderB1067 is the current fleet leader after completing 24th, 25th, 26th, 27th, 28th, 29th, 30th, and 31st launch & landings, the first to do so.^[87] Amongst all B5 boosters, B1058 holds the record for most spacecraft (869) launched to orbit, while the record for most spacecraft mass launched to orbit by a single booster is held byB1069 (401,140 kg (884,360 lb)).B1063 is currently and of all time, the oldest surviving booster in the Falcon 9 fleet.

As of 24 October 2025^[update], SpaceX has put into service a total of 52 new B5 boosters, of which 30 have been destroyed (21 have been expended, six have been lost due to failed landings, and three have been lost during recovery).