Falcon 9

As early as October 2005, SpaceX had publicly announced plans to launch Falcon 9 in the first half of 2007.[24] In the event, the first launch would occur in 2010.

While SpaceX exclusively spent its own money to develop its previous launcher, the Falcon 1, development of the Falcon 9 was accelerated by NASA funding parts of development costs and committing to purchase several commercial flights if specific capabilities were demonstrated. This started with seed money from the Commercial Orbital Transportation Services (COTS) program in 2006.[25][26] The contract was structured as a Space Act Agreement (SAA) "to develop and demonstrate commercial orbital transportation service"[26], including the purchase of three demonstration flights.[27] The overall contract award was US$278 million to provide development funding for Dragon, Falcon 9, and demonstration launches of Falcon 9 with Dragon. In 2011 additional milestones were added, bringing the total contract value to US$396 million.[28]

NASA became an anchor tenant for the vehicle in 2008,[29][30] when they contracted to purchase 12 Commercial Resupply Services launches to the International Space Station, whereby funds would be disbursed only after the initial COTS demonstration missions were completed and deemed successful. The space logistics delivery contract was worth US$1.6 billion for a minimum of 12 missions to carry supplies to and from the station.[31]

Musk has repeatedly said that, without the NASA money, the development would have taken longer.

SpaceX has only come this far by building upon the incredible achievements of NASA, having NASA as an anchor tenant for launch, and receiving expert advice and mentorship throughout the development process. SpaceX would like to extend a special thanks to the NASA COTS office for their continued support and guidance throughout this process. The COTS program has demonstrated the power of a true private/public partnership, and we look forward to the exciting endeavors our team will accomplish in the future.[29]

In 2011, SpaceX estimated that Falcon 9 v1.0 development costs were on the order of $300 million.[32] NASA evaluated that development costs would have been $3.6 billion if a traditional cost-plus contract approach had been used.[33] In 2014, SpaceX released total combined development costs for both the Falcon 9 and the Dragon capsule. NASA provided US$396 million, while SpaceX provided over US$450 million to fund rocket and capsule development efforts.[34]

A 2011 NASA report "estimated that it would have cost the agency about US$4 billion to develop a rocket like the Falcon 9 booster based upon NASA's traditional contracting processes" while "a more 'commercial development' approach might have allowed the agency to pay only US$1.7 billion."[35]

Congressional testimony by SpaceX in 2017 suggested that the unusual NASA process of "setting only a high-level requirement for cargo transport to the space station [while] leaving the details to industry" had allowed SpaceX to design and develop the Falcon 9 rocket on its own at substantially lower cost. "According to NASA's own independently verified numbers, SpaceX's development costs of both the Falcon 1 and Falcon 9 rockets were estimated at approximately US$390 million in total."[35]

SpaceX originally intended to follow its light Falcon 1 launch vehicle with an intermediate capacity vehicle, the Falcon 5.[36] In 2005, SpaceX announced it was instead proceeding with the development of the Falcon 9, a "fully reusable heavy-lift launch vehicle", and had already secured a government customer. The Falcon 9 was described as being capable of launching approximately 9,500 kg (21,000 lb) to low Earth orbit, and was projected to be priced at $27 million per flight with a 3.7 m (12 ft) payload fairing and $35 million with a 5.2 m (17 ft) fairing. SpaceX also announced the development of a heavy version of the Falcon 9 with a payload capacity of approximately 25,000 kg (55,000 lb).[37] The Falcon 9 was intended to enable launches to LEO, GTO, as well as both crew and cargo vehicles to the ISS.[36]

The original NASA COTS contract called for the first demonstration flight of Falcon in September 2008, and the completion of all three demonstration missions by September 2009.[38] In February 2008, the plan for the first Falcon 9/Dragon COTS Demo flight was delayed by six months into the first quarter of 2009. According to Elon Musk, the complexity of the development work and the regulatory requirements for launching from Cape Canaveral contributed to the delay.[39]

The first multi-engine test (with two engines connected to the first stage, firing simultaneously) was completed in January 2008,[40] with successive tests leading to the full Falcon 9 complement of nine engines test-fired for a full mission length (178 seconds) of the first stage in November 2008.[41] In October 2009, the first flight-ready first stage had a successful all-engine test fire at the company's test stand in McGregor, Texas. In November 2009 SpaceX conducted the initial second stage test firing lasting forty seconds. This test succeeded without aborts or recycles. In January 2010, a full-duration (329 seconds) orbit-insertion firing of the Falcon 9 second stage was conducted at the McGregor test site.[42] The full stack arrived at the launch site for integration at the beginning of February 2010, and SpaceX initially scheduled launch date of March 2010. However, they estimated anywhere between one and three months for integration and testing.[43]

In February 2010, SpaceX's first flight stack was set vertical at Space Launch Complex 40, Cape Canaveral,[44] and on March 9, SpaceX performed a static fire test, where the first stage was to be fired without taking off. The test aborted at T−2 seconds due to a failure in the system designed to pump high-pressure helium from the launch pad into the first stage turbopumps, which would get them spinning in preparation for launch. A subsequent review showed that the failure occurred when a valve did not receive a command to open. As the problem was with the pad and not with the rocket itself, it didn't happen at the McGregor test site, which did not have the same valve setup. Some fire and smoke were seen at the base of the rocket, leading to speculation of an engine fire. However, the fire and smoke were the results of normal burnoff from the liquid oxygen and fuel mix present in the system prior to launch, and no damage was sustained by the vehicle or the test pad. All vehicle systems leading up to the abort performed as expected, and no additional issues were noted that needed addressing. A subsequent test on March 13 was successful in firing the nine first-stage engines for 3.5 seconds.[45]

In December 2010, the SpaceX production line was manufacturing one Falcon 9 (and Dragon spacecraft) every three months, with a plan to double the rate to one every six weeks.[46] By September 2013, SpaceX's total manufacturing space had increased to nearly 1,000,000 sq ft (93,000 m²), and the factory had been configured to achieve a maximum production rate of 40 rocket cores per year.[47] The factory was producing one Falcon 9 vehicle per month as of November 2013. The company planned to increase to 18 vehicles per year in mid-2014, 24 per year by the end of 2014,[48][49] and 40 rocket cores per year by the end of 2015.[50]

These production rates were not achieved by February 2016 as previously planned; the company indicated that production rate for Falcon 9 cores had only recently increased to 18 per year, and the number of first stage cores that can be assembled at one time had doubled from three to six. The production rate was expected to grow to 30 cores per year by the end of 2016,[51]. Still, as of August 2016, SpaceX was working towards a production capacity of 40 cores per year,[52] the full factory capacity envisioned in 2013.[47][53]

Falcon 9 Flight 20 historic first-stage landing at CCAFS Landing Zone 1, on December 21, 2015

• Flight 1, Dragon Spacecraft Qualification Unit, first flight of Falcon 9 and first test of Dragon
• Flight 3, Dragon C2+, first cargo delivery to the International Space Station
• Flight 6, CASSIOPE, first v1.1 rocket, first launch from Vandenberg, first attempt at propulsive return of the first stage
• Flight 7, SES-8, first launch to GTO, first commercial payload (communications satellite)
• Flight 9, CRS-3, added landing legs, first fully controlled descent and vertical ocean touchdown
• Flight 15, DSCOVR, first mission passing escape velocity to the L1 point
• Flight 19, CRS-7, total loss of mission due to structural failure and helium overpressure in the second stage
• Flight 20, Orbcomm OG-2, first vertical landing of an orbital-class rocket
• Flight 23, CRS-8, first vertical landing achieved on an autonomous spaceport drone ship at sea
• Amos-6, total vehicle and payload loss prior to static fire test (would have been flight 29)
• Flight 30, CRS-10, first launch from LC-39A at the Kennedy Space Center
• Flight 32, SES-10, first reflight of a previously flown orbital class booster (B1021, previously used for CRS-8),[55] first recovery of a fairing[56]
• Flight 41, Boeing X-37B OTV-5, first launch of a spaceplane
• Flight 54, Bangabandhu-1, first flight of the Block 5 version
• Flight 58, Telstar 19V, heaviest communications satellite ever delivered to GEO[57]
• Flight 69, Crew Dragon Demo-1, first launch of the Crew Dragon
• Flight 72, RADARSAT Constellation, the most valuable commercial payload put into orbit[58][59][60]
• Flight 85, Crew Dragon Demo-2, first crewed launch of the Crew Dragon

A Falcon 9 v1.0 being launched with a Dragon spacecraft to deliver cargo to the ISS in 2012

The first version of the Falcon 9 launch vehicle, Falcon 9 v1.0, was an expendable launch vehicle that was developed in 2005–2010, and was launched for the first time in 2010. Falcon 9 v1.0 made five flights in 2010–2013, after which it was retired.

Falcon 9 v1.0 (left) and v1.1 (right) engine configurations

The Falcon 9 v1.0 first stage was powered by nine Merlin 1C rocket engines arranged in a 3×3 pattern. Each of these engines had a sea-level thrust of 556 kN (125,000 pounds-force) for a total thrust on liftoff of about 5,000 kN (1,100,000 pounds-force).[5] The Falcon 9 v1.0 second stage was powered by a single Merlin 1C engine modified for vacuum operation, with an expansion ratio of 117:1 and a nominal burn time of 345 seconds. Gaseous N₂ thrusters were used on the Falcon 9 v1.0 second-stage as a reaction control system.[72]

SpaceX expressed hopes initially that both stages would eventually be reusable.[73] But early results from adding lightweight thermal protection system capability to the booster stage and using parachute recovery were not successful,[74] leading to abandonment of that approach and the initiation of a new design. In 2011, SpaceX began a formal and funded development program for a reusable Falcon 9, with the early program focus however on return of the first stage.[65]

The launch of the first Falcon 9 v1.1 from SLC-4, Vandenberg AFB (Falcon 9 Flight 6) in September 2013

The Falcon 9 v1.1 is a 60 percent heavier rocket with 60 percent more thrust than the v1.0 version of the Falcon 9.[66] It includes realigned first-stage engines[75] and 60 percent longer fuel tanks, making it more susceptible to bending during flight.[66] Development testing of the v1.1 first stage was completed in July 2013.[76][77] The Falcon 9 v1.1, first launched in September 2013, uses a longer first stage powered by nine Merlin 1D engines arranged in an "octagonal" pattern,[78][79] that SpaceX calls Octaweb. This is designed to simplify and streamline the manufacturing process.[80]

The v1.1 first stage has a total sea-level thrust at liftoff of 5,885 kN (1,323,000 lbf), with the nine engines burning for a nominal 180 seconds, while stage thrust rises to 6,672 kN (1,500,000 lbf) as the booster climbs out of the atmosphere.[4] The engines have been upgraded to the more powerful Merlin 1D. These improvements increased the payload capability from 9,000 kg (20,000 lb) to 13,150 kg (28,990 lb).[4] The stage separation system has been redesigned and reduces the number of attachment points from twelve to three,[66] and the vehicle has upgraded avionics and software as well.[66] Following the September 2013 launch, the second stage igniter propellant lines were insulated to better support in-space restart following long coast phases for orbital trajectory maneuvers.[48]

SpaceX President Gwynne Shotwell has stated the Falcon 9 v1.1 has about 30 percent more payload capacity than published on its standard price list, the extra margin reserved for returning of stages via powered re-entry.[81] Four extensible carbon fiber with aluminum honeycomb landing legs were included on later flights where landings were attempted.[82][83][84]

The v1.2 upgrade, also known as "Full Thrust",[85][86] has cryogenic cooling of propellant to increase density allowing 17% higher thrust, an improved stage separation system, a stretched upper stage that can hold additional propellant, and strengthened struts for holding helium bottles believed to have been involved with the failure of flight 19.[87]

SpaceX pricing and payload specifications published for the Falcon 9 v1.1 rocket as of March 2014 actually included about 30 percent more performance than the published price list indicated; the additional performance was reserved for SpaceX to perform reusability testing with the Falcon 9 v1.1 while still achieving the specified payloads for customers. Many engineering changes to support reusability and recovery of the first stage had been made on the v1.1 version and testing was successful, with SpaceX able to increase the payload performance for the Full Thrust version, or decrease launch price, or both.[88]

The Full Thrust version of the rocket has a reusable first stage after achieving its first successful landing in December 2015[89] and the first reflight in March 2017.[90] However, plans to reuse the Falcon 9 second-stage booster have been abandoned as the weight of a heat shield and other equipment would impinge on payload too much for this to be economically feasible for this rocket.[17] The reusable booster stage was developed using systems and software tested on the Falcon 9 prototypes, as well as a set of technologies being developed by SpaceX to facilitate rapid reusability.

A close-up of the newer titanium grid fins first flown for the second Iridium NEXT mission in June 2017

In February 2017, SpaceX's CRS-10 launch was the first operational launch utilizing the new Autonomous Flight Safety System (AFSS) built into Falcon 9 Full Thrust launch vehicles. For all SpaceX launches after March 16, 2017, the autonomous AFSS has replaced "the ground-based mission flight control personnel and equipment with on-board Positioning, Navigation and Timing sources and decision logic. The benefits of AFSS include increased public safety, reduced reliance on range infrastructure, reduced range spacelift cost, increased schedule predictability and availability, operational flexibility, and launch slot flexibility."[91]

On the June 25, 2017, a space mission carried the second batch of ten Iridium NEXT satellites, during which their aluminum grid fins were replaced by titanium versions, to improve control authority and better heat tolerance during re-entry.[92]

In 2017, SpaceX started including incremental changes to the Falcon 9 Full Thrust, internally calling it the "Block 4" version.[93] Initially, only the second stage was modified to Block 4 standards, flying on top of a "Block 3" first stage for three missions: NROL-76 and Inmarsat-5 F4 in May 2017, and Intelsat 35e in July.[94] Block 4 was described as a transition between the Full Thrust v1.2 "Block 3" and Block 5. It includes incremental engine thrust upgrades leading to the final thrust for Block 5.[95] The maiden flight of the full Block 4 design (first and second stages) was the NASA CRS-12 mission on August 14, 2017.[96]

In October 2016, Musk described a Block 5 version that would have "a lot of minor refinements that collectively are important, but uprated thrust and improved legs are the most significant."[97] In January 2017, Musk added that the Block 5 version "significantly improves performance & ease of reusability".[98] He described this version as the "final" version of the rocket.[97] The maiden flight took place on May 11, 2018,[23] with the Bangabandhu-1 satellite.[99] The Block 5 version of the second stage includes upgrades that enable it to operate for longer in orbit and reignite its engine three or more times.[100]

SpaceX had predicted that its launches would have high reliability based on the philosophy that "through simplicity, reliability and low cost can go hand-in-hand" by 2011.[113] As of 13 June 2020, the Falcon 9 has achieved 88 out of 90 full mission successes (97.8%), with SpaceX CRS-1 succeeding in the primary mission but leaving a secondary payload in a wrong orbit and SpaceX CRS-7 destroyed in flight. In addition Amos-6 was destroyed on the launch pad during fueling for an engine test. For comparison, present industry benchmark, the Russian Soyuz series has performed more than 1,700 launches[114] with a success rate of 97.4%,[115] the Russian Proton series has performed 422 launches a success rate of 88.6%, the European Ariane 5 has performed 105 launches with a success rate of 95.2%, and Chinese Long March 3B has performed 67 launches with a success rate of 94%.

As with the company's smaller Falcon 1 vehicle, Falcon 9's launch sequence includes a hold-down feature that allows full engine ignition and systems check before liftoff. After first-stage engine start, the launcher is held down and not released for flight until all propulsion and vehicle systems are confirmed to be operating normally. Similar hold-down systems have been used on other launch vehicles such as the Saturn V[116] and Space Shuttle. An automatic safe shut-down and unloading of propellant occur if any abnormal conditions are detected.[5] Prior to the launch date, SpaceX always completes a test of the Falcon 9, culminating in a firing of the first stage's Merlin 1D engines for three-and-a-half seconds to verify performance.[117]

Falcon 9 has triple-redundant flight computers and inertial navigation, with a GPS overlay for additional orbit insertion accuracy.[5]

Like the Saturn rocket series from the Apollo program, the presence of multiple first-stage engines allows for mission completion even if one of the first-stage engines fails during flight.[5][118] Detailed descriptions of several aspects of destructive engine failure modes and designed-in engine-out capabilities were made public by SpaceX in a 2007 "update" that was publicly released.[119]

SpaceX emphasized over several years that the Falcon 9 first stage is designed for engine out capability.[5] The SpaceX CRS-1 mission in October 2012 was a partial success after an engine failure in the first stage: engine no. 1 experienced a loss of pressure at 79 seconds, and then shut down. To compensate for the resulting loss of acceleration, the first stage had to burn 28 seconds longer than planned, and the second stage had to burn an extra 15 seconds. That extra burn time of the second stage reduced its fuel reserves, so that the likelihood that there was sufficient fuel to reach the planned orbit above the space station with the secondary payload dropped from 99% to 95%. Because NASA had purchased the launch and therefore contractually controlled several mission decision points, NASA declined SpaceX's request to restart the second stage and attempt to deliver the secondary payload into the correct orbit. The secondary payload customer understood this risk at time of the signing of the launch contract. As a result, the secondary payload satellite reentered the atmosphere a few days after launch.[8]

On a March 18, 2020 Starlink mission, one of the first stage engines failed 3 seconds before the main engine cut-off. The payload was inserted into the correct orbit, but the booster recovery failed. SpaceX stated in the webcast of the next Starlink mission that the engine had failed due to the ignition of some isopropyl alcohol that was not properly purged after cleaning the engine.[120]

The first reflight of an orbital class rocket, by SpaceX in March 2017

SpaceX intended to recover the first stages of several early Falcon flights to assist engineers in designing for future reusability. They were equipped with parachutes but failed to survive the aerodynamic stress and heating during atmospheric re-entry following stage separation.[74] Although reusability of the second stage is more difficult, SpaceX intended from the beginning to make both stages of the Falcon 9 reusable.[121] Both stages in the early launches were covered with a layer of ablative cork and had parachutes to land them gently in the sea. The stages were also marinized by salt-water corrosion-resistant material, anodizing and paying attention to galvanic corrosion.[121] Musk said that if the vehicle does not become reusable, "I will consider us to have failed."[122]

In late 2011, SpaceX announced a change in the approach, eliminating the parachutes and going with a propulsively-powered-descent approach.[123][124] Included was a video[125] said to be an approximation depicting the first stage returning tail-first for a powered descent and the second stage, with heat shield, reentering head first before rotating for a powered descent.[124][126] The design was complete on the system for "bringing the rocket back to launchpad using only thrusters" by February 2012.[65]

A reusable first stage was then flight-tested by SpaceX with the suborbital Grasshopper rocket.[127] Between 2012 and 2013, this low-altitude, low-speed demonstration test vehicle made eight VTVL test flights, including a 79-second round-trip flight to an altitude of 744 m (2,441 ft). In March 2013, SpaceX announced that beginning with the first flight of the Falcon 9 v1.1 (the sixth flight overall of Falcon 9), every first stage would be instrumented and equipped as a controlled descent test vehicle. SpaceX continued their propulsive-return over-water tests, saying they "will continue doing such tests until they can do a return to the launch site and a powered landing. ... [SpaceX] expect several failures before they 'learn how to do it right.'"[83]

Falcon 9 Flight 17's first stage attempting a controlled landing on the Autonomous Spaceport Drone Ship following the launch of CRS-6 to the ISS in April 2015.

For Falcon 9 Flight 6 in September 2013, after stage separation, the flight test plan called for the first-stage booster to first burn to reduce its reentry velocity, and then effect a second burn just before it reached the water. SpaceX stated they expected several powered-descent tests to achieve successful recovery,[84] before they could then attempt a landing on a solid surface.[83] Although not a complete success, the stage was able to change direction and make a controlled entry into the atmosphere.[128] During the final landing burn, the ACS thrusters could not overcome an aerodynamically induced spin. The centrifugal force deprived the landing engine of fuel leading to early engine shutdown and a hard splashdown that destroyed the first stage.[128]

After four more ocean landing tests, the first stage of the CRS-5 launch vehicle attempted a landing on a floating landing platform, the "Autonomous Spaceport Drone Ship" (ASDS) in January 2015. The rocket incorporated (for the first time in an orbital mission) grid fin aerodynamic control surfaces, and guided itself to the ship successfully, but ran out of hydraulic fluid and lost its steering ability, destroying it on impact with the landing platform.[129] A second attempt to land on a floating platform occurred in April 2015, on CRS-6. After the launch, Elon Musk communicated that the bipropellant valve had become stuck, and therefore the control system could not react rapidly enough for a successful landing.[130]

The first attempt to land the first stage of Falcon 9 on a ground pad near the launch site occurred on flight 20, the maiden flight of the Falcon 9 Full Thrust version in December 2015. The landing was successful and the first stage was recovered.[131][132] This was the first time in history that a rocket first stage returned to Earth after propelling an orbital launch mission and achieving a controlled vertical landing. The first successful first-stage landing on an ASDS occurred in April 2016 on the drone ship Of Course I Still Love You during the CRS-8 mission.

In total, sixteen test flights were conducted from 2013 to 2016, six of which achieved a soft landing and recovery of the booster. Since January 2017, SpaceX has stopped referring to landing attempts as "experimental" in their press releases, indicating that they are now considered a routine procedure; with the exceptions of the center core from the Falcon Heavy Test Flight, Falcon Heavy USAF STP-2 mission, the Falcon 9 CRS-16 resupply mission and the Starlink 4 and 5 (version 1.0) missions, every landing attempt since has been successful. The only post-landing loss of a first stage occurred on Falcon Heavy Arabsat-6A after the center core fell overboard during rough seas on trip to land.

The first operational reuse of a previously-flown Falcon 9 booster was accomplished in March 2017[133] with B1021 on the SES-10 mission after CRS-8 in April 2016.[134] The booster landed a second time and was retired.[135] In June 2017, booster B1029 helped carry BulgariaSat-1 towards GTO after an Iridium NEXT LEO mission in January, again achieving the reuse and second landing of a recovered booster.[136] The third flight of a reused booster was first performed in November 2018 on the SSO-A mission. The core for the mission, B1046, was the first Block 5 booster produced, flown initially on the Bangabandhu-1 mission.[137]

Despite public statements that they would endeavor to make the Falcon 9 second-stage reusable as well, by late 2014, SpaceX determined that the mass needed for a re-entry heat shield, landing engines, and other equipment to support recovery of the second stage was at that time prohibitive, and indefinitely suspended their second-stage reusability plans for the Falcon line.[17][138] However, in 2017 they indicated that they might do experimental tests on recovering one or more second-stages to learn more about reusability to inform their new, much-larger, Starship launch vehicle development process.[139] Elon Musk announced April 15, 2018 that the company will be returning the second stage of a future Falcon 9 mission using "a giant party balloon".[140]

Payload fairings have survived descent and splashdown in the Pacific Ocean. In June 2015, wreckage of an unidentified Falcon 9 launch vehicle was found off the coast of The Bahamas, which was confirmed by SpaceX CEO Elon Musk to be a component of the payload fairing that washed ashore. Musk noted the possibility of fairing reusability in a statement: "This is helpful for figuring out fairing reusability."[141] In March 2017, SpaceX for the first time recovered a fairing from the SES-10 mission, aided by thrusters and a steerable parachute helping it glide towards a gentle touchdown on water.[56]

On April 11, 2019, SpaceX recovered both fairing halves during the Arabsat-6A mission. Following stage separation, the fairing pieces were ejected and fell back to Earth. The pieces landed in the Atlantic Ocean intact and were recovered by the SpaceX recovery teams. Following recovery, Elon Musk tweeted that the fairing halves were successfully recovered and were going to be refurbished for a Starlink launch.[142] Starting in June 2019 SpaceX managed to catch fairing parts with a big net on a ship, avoiding contact with corrosive saltwater.[143]

In November 2018, SpaceX announced work on a heavily modified Falcon 9 second stage that would be used for atmospheric reentry testing of a number of technologies needed for the full-scale Starship, including an ultra-light heat shield and high-Mach control surfaces. Musk indicated it would be "upgraded to be like a mini-BFR ship" but that the stage would not be used for landing tests, as the company already believes it has a good handle on propulsive landings. In November 2018, the first test flight of the modified stage was planned to be no earlier than mid-2019.[144] In the event, the design work did not proceed all the way to flight testing, and no reentry tests were done using a returning Falcon 9 second stage. All SpaceX second stage design/development work for atmospheric reentry moved to the two Starship orbital prototype vehicles.[145]

Falcon 9 payload services include secondary and tertiary payload connection via an EELV Secondary Payload Adapter ring, the same interstage adapter first used for launching secondary payloads on US DoD missions that use the Evolved Expendable Launch Vehicles (EELV) Atlas V and Delta IV. This enables secondary and even tertiary missions with minimal impact to the original mission. In 2011, SpaceX announced pricing for ESPA-compatible payloads on the Falcon 9.[162]