Falcon 9 is a two-stage rocket. It was designed and manufactured by SpaceX in the United States. Parts of the rocket can be used more than one time. The latest version of the first stage can return to Earth and be flown again many times. Both the first and second stages are powered by SpaceX Merlin engines. They use cryogenic liquid oxygen and rocket-grade kerosene (RP-1) as feul. Its name comesfrom the fictional Star Wars spacecraft, the Millennium Falcon. The 9 is for the nine engines of the rocket's first stage. There have been many versions of the rocket. These include v1.0 (2010–2013), v1.1 (2013–2016) and  v1.2 Full Thrust (2015–present). It also includes the Falcon 9 Block 5 version.

It also includes the Block 5 Full Thrust version. This version has been used since May 2018. Most rockets can only be used one time. SpaceX has landed Falcon 9 boosters over a hundred times.  The first stages have been used as many as eleven times.

Falcon 9 can carry of up to  to low Earth orbit (LEO). If fully used, it can carry  to geostationary transfer orbit (GTO). The rocket can carry  to GTO when the first stage is recovered. It has a cargo size of ]145 cubic meters of volume The heaviest GTO loads carried have been Intelsat 35e () and Telstar 19V ().   

In 2008, SpaceX won a Commercial Resupply Services (CRS) contract in NASA's Commercial Orbital Transportation Services (COTS) program. They would take cargo to the International Space Station (ISS) using the Falcon 9 and Dragon capsule. The first mission under this contract launched on 8 October 2012. Falcon 9 can take NASA astronauts to the ISS. It is also certified for the National Security Space Launch program and NASA Launch Services Program as "Category 3". This means it can be used with the most expensive, important and complex NASA missions. Falcon 9 is said to be the world's most advanced space launch vehicle by many sources. As of January 2021, Falcon 9 has the most launches among all U.S. rockets that are currently being used. It is the only U.S. rocket fully certified for transporting humans to the International Space Station. It is also the only commercial rocket to take humans to orbit. On 24 January 2021, Falcon 9 set a new record for the most satellites launched by a single rocket. It carried 143 satellites into orbit.

Five rockets of the version 1.0 design were launched from June 2010 to March 2013. Version 1.1 had fifteen launches from September 2013 to January 2016. The "Full Thrust" version has been used since December 2015. There are many upgrades to this version. The latest Full Thrust variant, Block 5, was introduced in May 2018. It has more thrust, improved landing legs and other minor improvements to help recovery and reuse. The Falcon Heavy version was first flown in February 2018. It has a stronger Falcon 9 first stage as its center core. It also has two added Falcon 9 first stages used as boosters. SpaceX plans to replace Falcon 9 and Falcon Heavy with the much larger Starship launch system.

Development history

Conception and funding 
In October 2005, SpaceX said it was going to launch Falcon 9 in the first half of 2007. The first launch took place in 2010.

SpaceX spent its own money to create the Falcon 1. Creating the Falcon 9 was faster because NASA helped with the cost. They also said they would buy several commercial flights. This started with money from the Commercial Orbital Transportation Services (COTS) program in 2006. The contract was a Space Act Agreement (SAA) "to develop and demonstrate commercial orbital transportation service". It included NASA paying for of three demonstration flights. The contract was US$278 million to provide development funding for Dragon, Falcon 9, and demonstration launches of Falcon 9 with Dragon. In 2011 other milestones were added, This made the total contract value US$396 million.

NASA became the main user for the vehicle in 2008. They agreed to buy 12 Commercial Resupply Services launches to the International Space Station. The money would be paid after the demonstration missions were completed successfully. The space logistics delivery contract was worth US$1.6 billion for a minimum of 12 missions to carry supplies to and from the International Space Station.

Elon Musk has said that it would have taken longer without the NASA money.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.

In 2011, SpaceX saidthat Falcon 9 v1.0 costs were about US$300 million. NASA said that costs would have been US$3.6 billion if a traditional cost-plus contract approach had been used. In 2014, SpaceX released total costs for both the Falcon 9 and the Dragon capsule. NASA provided US$396 million. SpaceX provided over US$450 million.

A 2011 NASA report said that it would have cost them about US$4 billion to develop a rocket like the Falcon 9 booster. "A more commercial development" approach might have let the agency to pay only US$1.7 billion".

Congressional testimony by SpaceX in 2017 said that the normal NASA process of setting only a requirement and leaving the details to SpaceX let them make the Falcon 9 rocket at a muchlower cost.

Development 
At first, SpaceX wanted to follow the Falcon 1 with a larger capacity vehicle, the Falcon 5. In 2005, SpaceX said it was working on the Falcon 9 instead. They said that they already had a government customer. The Falcon 9 was said to be able of carrying approximately  to low Earth orbit. They said it would cost US$27 million per flight with a  payload. It would cost US$35 million with a  payload. SpaceX also said a heavy version of the Falcon 9 would have a payload capacity of about . The Falcon 9 was intended to enable launches to Low-Earth orbit (LEO), Geosynchronous Transfer Orbit (GTO), as well as both crew and cargo vehicles to the International Space Station (ISS). The rocket was not full reusable at this time. This caused the price estimates to be higher than expected.

Testing 
The original NASA contract called for a demonstration flight of Falcon in September 2008. It also called for all three demonstration missions to be done by September 2009. In February 2008, the plan for the first demo flight was delayed until early 2009. According to Elon Musk, the delay was  caused by how cpmplex the work was the rules for launching from Cape Canaveral.

The first test with two engines connected to the first stage was done in January 2008. Other tests led to the Falcon 9 being tested with nine engines. The engine were tested for a full mission length (178 seconds for stage one) in November 2008. In October 2009, the first stage had a successful all-engine test fire for the first time. This was done  in McGregor, Texas. In November 2009, SpaceX held the first test of the second stage. This test lasted forty seconds. In January 2010, a full-duration (329 seconds)  firing of the Falcon 9 second stage was held. SpaceX  scheduled launch date of March 2010. 

In February 2010, SpaceX's first flight stack was set up at Space Launch Complex 40, Cape Canaveral. On 9 March 2010, SpaceX  was to test-fire the first stage. The test was stopped 2 seconds before firing. This was because of a failure in the system designed to pump high-pressure helium from the launch pad into the first stage. The problem was with the pad and not with the rocket itself. All of Falcon 9's systems leading up to the abort worked as expected. Another test on 13 March 2010 was successful.

Production 
In December 2010, SpaceX was making one Falcon 9 (and Dragon spacecraft) every three months. They wanted to double the rate to one every six weeks. By September 2013, SpaceX's manufacturing space had increased to nearly . The factory had set up to make 40 rocket cores per year. The factory was making one Falcon 9 vehicle per month as of November 2013. The company wanted to increase that to 18 vehicles per year in mid-2014 and  24 per year by the end of 2014. They wanted to be making 40 rocket cores per year by the end of 2015.

These production rates were not achieved by February 2016. The company said that production rate for Falcon 9 cores had only increased to 18 per year. They also said that the number of first stage cores that can be made at one time had doubled from three to six. The rate was expected to grow to 30 cores per year by the end of 2016. Still, By August 2016, SpaceX was working towards a production capacity of 40 cores per year. 

Since 2018, SpaceX has usually reused first stages. This has reduced the need for new cores. In 2021, SpaceX had 31 F9 launches. Only two of those used new boosters. They recovered the booster on all but one flight.

Design 

The Falcon 9 is a two-stage rocket. it is powered by LOX and RP-1.   Both stages have Merlin 1D rocket engines. The first stage has nine that are adapted for use at sea-level. The second stage has one that is adapted for use in a vacuum. The engines uses a pyrophoric mixture of triethylaluminum-triethylborane (TEA-TEB) to ignite the engine. The first stage engines are set in a form SpaceX calls "Octaweb." Many cores have four landing legs at the base of the Octaweb. To control the core while it falls through the atmosphere, SpaceX uses grid fins. They deploy from the vehicle after separation. The legs deploy moments before landing.

The propellant tank walls and domes are made from aluminum–lithium alloy.  The second stage tank of a Falcon 9 is a shorter version of the first stage tank. This decreases the cost to make them. The connection between the two stages is a carbon-fiber and aluminum-core structure. The original stage separation system had twelve attachment points. This was which was reduced to three in the v1.1 launcher.

The Falcon 9 uses a payload fairing to protect satellites during launch. The fairing is  long,  in diameter, weighs approximately .  It is made of a carbon fiber skin on an aluminum honeycomb core. Testing of the design was done at NASA's Plum Brook Station facility in spring 2013.

SpaceX uses multiple flight computers. This makes the system less affected by faults. Each Merlin rocket engine is controlled by three computers. Each of these computers has two processors that check each other. The software runs on Linux. It is written in C++. Each stage has its own flight computers. This is in addition to the controllers on each engine.  Each engine microcontroller CPU runs on a PowerPC architecture.

The Falcon 9 rocket can lose up to two of the engines and still complete the mission. Each engine creates  of thrust.

Launcher versions 
The Falcon 9 v1.0 flew five times in 2010–2013. The Falcon 9 v1.1 made its first flight in September 2013. The mission carried a very small  payload, the CASSIOPE satellite. It later launched larger things. This included the SES-8 GEO communications satellite. Both Falcon 9 v1.0 and Falcon 9 v1.1 were expendable launch vehicles (ELVs). The Falcon 9 Full Thrust made its first flight in December 2015. The first stage of the Falcon 9 Full Thrust version can be used many times. The current version, known as Falcon 9 Block 5, made its first flight in May 2018.

Pricing 
In 2010, the price of a Falcon 9 v1.0 launch was US$49.9 to US$56 million. By 2012, the listed price range had increased to US$54–US$59.5 million. In August 2013, the price for a Falcon 9 v1.1 was US$56.5 million; it was raised to US$61.2 million by June 2014. Since May 2016, the price for a Falcon 9 Full Thrust mission (allowing booster recovery) is US$62 million. Dragon cargo missions to the ISS have an average cost of US$133 million  The DSCOVR mission, for National Oceanic and Atmospheric Administration (NOAA), cost US$97 million.

In 2004, Elon Musk said "long term plans call for development of a heavy lift product and even a super-heavy, if there is customer demand. [...] Ultimately, I believe US$500 per pound (US$1100/kg) [of payload delivered to orbit] or less is very achievable". At its 2016 price, a Falcon 9 FT launch costs just over US.

In 2011, Musk estimated that materials needed for the Falcon 9 v1.0 launch cost about US$200,000. The first stage uses  of liquid oxygen and  of RP-1 fuel, while the second stage uses  of liquid oxygen and  of RP-1.

In October 2019, data from NASA showed that the Falcon 9's "base price" of US$62 million per launch would be lowered to US$52 million for flights scheduled in 2021 and beyond.

CNBC reported in April 2020 that the United States Air Force's launches were costing US$95 million This was because of the extra security used. SpaceX executive Christopher Couluris stated that reusing rockets can bring prices even lower, that it "costs US$28 million to launch it, that's with everything".

Gallery

References

Other Websites 

 Falcon 9 official page
 SAOCOM 1B | Launch and Landing
 Test firing of two Merlin 1C engines connected to Falcon 9 first stage, Movie 1, Movie 2 (18 January 2008)
 Press release announcing design (9 September 2005)
 SpaceX hopes to supply ISS with new Falcon 9 heavy launcher (Flight International, 13 September 2005)
 SpaceX launches Falcon 9, With A Customer  (Defense Industry Daily, 15 September 2005)

SpaceX
2010 establishments