Falcon Heavy is a partially reusable heavy-lift launch vehicle designed and manufactured by SpaceX. It is derived from the Falcon 9 vehicle and consists of a strengthened Falcon 9 first stage as the center core with two additional Falcon 9-like first stages as strap-on boosters. Falcon Heavy has the highest payload capacity of any currently operational launch vehicle, and the third-highest capacity of any rocket ever to reach orbit, trailing the Saturn V and Energia.

SpaceX conducted Falcon Heavy's maiden launch on 6 February 2018, at 20:45 UTC. The rocket carried a Tesla Roadster belonging to SpaceX founder Elon Musk, with a dummy dubbed "Starman" in the driver's seat, as a dummy payload. The second Falcon Heavy launch occurred on 11 April 2019 and all three booster rockets successfully returned to Earth. The third Falcon Heavy launch successfully occurred on 25 June 2019. Since then, Falcon Heavy has been certified for the National Security Space Launch (NSSL) program.

Falcon Heavy was designed to be able to carry humans into space beyond low Earth orbit, although as of February 2018, SpaceX has confirmed that they will not transport people on Falcon Heavy, nor pursue the human-rating certification process to transport NASA astronauts. Both Falcon Heavy and Falcon 9 will eventually be superseded by the in-development Starship launch system.

History

Concepts for a Falcon Heavy launch vehicle using three Falcon 1 core boosters were initially discussed as early as 2003. The concept for three core booster stages of the company's as-yet-unflown Falcon 9 was referred to in 2005 as the Falcon 9 Heavy.

SpaceX unveiled the plan for the Falcon Heavy to the public at a Washington, D.C. news conference in April 2011, with initial test flight expected in 2013.

A number of factors delayed the planned maiden flight by 5 years to 2018, including two anomalies with Falcon 9 launch vehicles, which required all engineering resources to be dedicated to failure analysis, halting flight operations for many months. The integration and structural challenges of combining three Falcon 9 cores were much more difficult than expected.

In July 2017, Elon Musk said, "It actually ended up being way harder to do Falcon Heavy than we thought. ... We were pretty naive about that".

The initial test flight for a Falcon Heavy lifted off on 6 February 2018, at 20:45 UTC, carrying its dummy payload, Elon Musk's personal Tesla Roadster, beyond Mars orbit.

Conception and funding

Musk mentioned Falcon Heavy in a September 2005 news update, referring to a customer request from 18 months prior. Various solutions using the planned Falcon 5 (which was never flown) had been explored, but the only cost-effective, reliable iteration was one that used a 9-engine first stage — the Falcon 9. The Falcon Heavy was developed with private capital with Musk stating that the cost was more than US$500 million. No government financing was provided for its development.

Design and development

The Falcon Heavy design is based on Falcon 9's fuselage and engines. By 2008, SpaceX had been aiming for the first launch of Falcon 9 in 2009, while "Falcon 9 Heavy would be in a couple of years". Speaking at the 2008 Mars Society Conference, Musk also indicated that he expected a hydrogen-fueled upper stage would follow 2–3 years later (which would have been around 2013).

By April 2011, the capabilities and performance of the Falcon 9 vehicle were better understood, SpaceX having completed two successful demonstration missions to low Earth orbit (LEO), one of which included reignition of the second-stage engine. At a press conference at the National Press Club in Washington, D.C. on 5 April 2011, Musk stated that Falcon Heavy would "carry more payload to orbit or escape velocity than any vehicle in history, apart from the Saturn V Moon rocket ... and Soviet Energia rocket". In the same year, with the expected increase in demand for both variants, SpaceX announced plans to expand manufacturing capacity "as we build towards the capability of producing a Falcon 9 first stage or Falcon Heavy side booster every week and an upper stage every two weeks".

In 2015, SpaceX announced a number of changes to the Falcon Heavy rocket, worked in parallel to the upgrade of the Falcon 9 v1.1 launch vehicle. In December 2016, SpaceX released a photo showing the Falcon Heavy interstage at the company headquarters in Hawthorne, California.

Testing

In April 2011, Musk was planning for a first launch of Falcon Heavy from Vandenberg Air Force Base on the West Coast in 2013. SpaceX refurbished Launch Complex 4E at Vandenberg AFB to accommodate Falcon 9 and Heavy. The first launch from the Cape Canaveral East Coast launch complex was planned for late 2013 or 2014.

Due partly to the failure of SpaceX CRS-7 in June 2015, SpaceX rescheduled the maiden Falcon Heavy flight in September 2015 to occur no earlier than April 2016, but by February 2016 had postponed it again to late 2016. The flight was to be launched from the refurbished Kennedy Space Center Launch Complex 39A.

In August 2016, the demonstration flight was moved to early 2017, then to summer 2017, to late 2017 and was launched in February 2018.

At a July 2017 meeting of the International Space Station Research and Development meeting in Washington, D.C., Musk downplayed expectations for the success of the maiden flight:

There's a real good chance the vehicle won't make it to orbit ... I hope it makes it far enough away from the pad that it does not cause pad damage. I would consider even that a win, to be honest.

In December 2017, Musk tweeted that the dummy payload on the maiden Falcon Heavy launch would be his personal Tesla Roadster playing David Bowie's "Life on Mars", and that it would be launched into an orbit around the Sun that will reach the orbit of Mars. He released pictures in the following days. The car had three cameras attached to provide "epic views".

On December 28, 2017, the Falcon Heavy was moved to the launch pad in preparation of a static fire test of all 27 engines, which was expected on 19 January 2018. However, due to the U.S. government shutdown that began on 20 January 2018, the testing and launch were further delayed.

The static fire test was conducted on 24 January 2018. Musk confirmed via Twitter that the test "was good" and later announced the rocket would be launched on 6 February 2018.

Maiden launch of the Falcon Heavy On 6 February 2018, after a delay of over two hours due to high winds, Falcon Heavy lifted off at 20:45 UTC. Its side boosters landed safely on Landing Zones 1 and 2 a few minutes later. However, only one of the three engines on the center booster that were intended to restart ignited during its descent, causing it to hit the water next to the droneship at a speed of over 480 km/h (300 mph).

Initially, Elon Musk tweeted that the Roadster had overshot its planned heliocentric orbit, and would reach the asteroid belt. In fact, observations by telescopes showed that the Roadster would only slightly exceed the orbit of Mars at aphelion.

Later flights

A year after the successful demo flight, SpaceX had signed five commercial contracts worth US$500–750 million, meaning that it had managed to cover the development cost of the rocket. The second flight, and first commercial one, occurred on 11 April 2019, launching Arabsat-6A, with all three boosters landing successfully for the first time.

The third flight occurred on 25 June 2019, launching the STP-2 (DoD Space Test Program) payload. The payload was composed of 25 small spacecraft. Operational Geostationary transfer orbit (GTO) missions for Intelsat and Inmarsat, which were planned for late 2017, were moved to the Falcon 9 Full Thrust rocket version as it had become powerful enough to lift those heavy payloads in its expendable configuration.

Following the announcement of NASA's Artemis program of returning humans to the Moon, the Falcon Heavy rocket has been mentioned several times as an alternative to the expensive Space Launch System (SLS) program. NASA director Jim Bridenstine announced that Falcon Heavy is powerful enough to launch the Orion capsule, but cannot launch it on top of the European Service Module in the same flight, and thus Falcon Heavy cannot be used as a replacement for SLS. However, Falcon Heavy will support commercial missions for the Artemis program, since it will be used to transport the Dragon XL spacecraft to the Gateway. It was also selected to launch the first two elements of the Lunar Gateway, the Power and Propulsion Element (PPE), and the Habitation And Logistics Outpost (HALO), on a single launch in 2026.

Design

Falcon Heavy consists of a structurally strengthened Falcon 9 as the "core" component, with two additional Falcon 9 first stages acting as liquid fuel strap-on boosters, which is conceptually similar to Evolved Expendable Launch Vehicle (EELV) Delta IV Heavy launcher and proposals for the Atlas V Heavy and Russian Angara A5V. Falcon Heavy has more lift capability than any other operational rocket, with a payload of 63,800 kg (140,700 lb) to low Earth orbit, 26,700 kg (58,900 lb) to Geostationary Transfer Orbit, and 16,800 kg (37,000 lb) to trans-Mars injection. The rocket was designed to meet or exceed all current requirements of human rating. The structural safety margins are 40% above flight loads, higher than the 25% margins of other rockets. Falcon Heavy was designed from the outset to carry humans into space and it would restore the possibility of flying crewed missions to the Moon or Mars.

The first stage is powered by three Falcon 9 derived cores, each equipped with nine Merlin 1D engines. The Falcon Heavy has a total sea-level thrust at liftoff of 22,819 kN (5,130,000 lbf), from the 27 Merlin 1D engines, while thrust rises to 24,681 kN (5,549,000 lbf) as the craft climbs out of the atmosphere. The upper stage is powered by a single Merlin 1D engine modified for vacuum operation, with a thrust of 934 kN (210,000 lbf), an expansion ratio of 117:1 and a nominal burn time of 397 seconds. At launch, the center core throttles to full power for a few seconds for additional thrust, then throttles down. This allows a longer burn time. After the side boosters separate, the center core throttles back up to maximum thrust. For added reliability of restart, the engine has dual redundant pyrophoric igniters (Triethylaluminium-Triethylborane) (TEA-TEB). The interstage, which connects the upper and lower stage for Falcon 9, is a carbon fiber aluminum core composite structure. Stage separation occurs via reusable separation collets and a pneumatic pusher system. The Falcon 9 tank walls and domes are made from Aluminium–lithium alloy. SpaceX uses an all-friction stir welded tank. The second stage tank of Falcon 9 is simply a shorter version of the first stage tank and uses most of the same tooling, material, and manufacturing techniques. This approach reduces manufacturing costs during vehicle production.

All three cores of the Falcon Heavy arrange the engines in a structural form SpaceX calls Octaweb, aimed at streamlining the manufacturing process, and each core includes four extensible landing legs. To control the descent of the boosters and center core through the atmosphere, SpaceX uses small grid fins which deploy from the vehicle after separation. Immediately after the side boosters separate, the center engine in each burns for a few seconds in order to control the booster's trajectory safely away from the rocket. The legs then deploy as the boosters turn back to Earth, landing each softly on the ground. The center core continues to fire until stage separation, after which its legs deploy and land back on Earth on a drone ship. The landing legs are made of carbon fiber with aluminum honeycomb structure. The four legs stow along the sides of each core during liftoff and later extend outward and down for landing.

(Wikipedia)