Falcon Heavy Compendium

This article will be regularly updated based on the latest information (list of recent changes can be found at the end of the article). You can easily access the article from the main menu in the “Compendiums” section.

Last Update: August 23, 2019
(changelog)

Falcon Heavy (Credit: SpaceX)

Falcon Heavy (FH) is the most powerful member of SpaceX’s Falcon rocket family. Public first learned about FH back in 2005, a few years before Falcon 1’s first successful launch. In 2008, Falcon Heavy’s first launch was scheduled for 2013. The inaugural launch kept being postponed and Falcon Heavy finally launched for the first time in February 2018.

The idea behind Falcon Heavy is simple, it’s basically three Falcon 9 boosters assembled together (however, Elon Musk revealed during the SES-10 press conference that FH’s development was far more challenging than originally expected). Falcon Heavy is powered by Merlin 1D engines and is the most powerful rocket currently in operation (it has the highest thrust and also the highest LEO payload capability). In addition, FH is able to launch large payloads beyond Earth’s orbit.

After the successful Falcon Heavy demonstration mission in February 2018, Elon Musk revealed that the rocket cost at least half a billion dollars to develop.

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Parameters

  • Price (real price could be higher based on type of mission and additional customer requirements):
    • 90 million USD (boosters recovered)
    • 95 million USD (only side boosters recovered)
    • 150 million USD (expendable)
  • Payload Capability:
    • LEO
      • 63,800 kg (expendable)
      • 30,000 kg (boosters recovered)
    • GTO
      • 26,700 kg (expendable)
      • 10,000 kg (all 3 boosters landing on droneships)
      • 8,000 kg (side booster landing on land, center booster landing on droneship)
    • Mars: 16,800 kg (expendable)
    • Pluto: 3,500 kg (expendable)
  • Height: 70 m (incl. second stage and fairing)
  • Width: 12.2 m (diameter of each stage: 3.66 m)
  • Total Mass (fueled): 1,420,788 kg
  • Total Thrust (at sea level): 22,819 kN
  • Propellants: RP-1 and liquid oxygen

Merlin Engine

Merlin 1D Block 5 (Credit: SpaceX)

Merlin is an open combustion cycle rocket engine running on RP-1 (highly refined kerosene) and liquid oxygen. SpaceX manufactures several hundred of these engines per year and is therefore also the world’s largest manufacturer of rocket engines. Merlin has undergone many changes over the years and there have been several variations. Falcon Heavy uses the latest version called Merlin 1D – the rocket’s first stage consists of three cores, each equipped with 9 Merlin 1D engines, and the upper stage is propelled by a single Merlin 1D-Vac engine (a modified engine variant optimized for vacuum).

Merlin 1D has the highest thrust-to-weight ratio (TWR) of all rocket engines in the world. It weighs 470 kg and the latest variant has a thrust of 845 kN at sea level (981 kN in vacuum for the vacuum engine variant). One of the advantages of the Merlin is its restartability (it can be easily turned off and later turned on again). This allows SpaceX to test fire each engine prior to actual launch and it also enables the first stage to land, which requires several engine restarts.

Another advantage is regenerative cooling that makes the Merlin easy to reuse. The principle behind regenerative cooling is that, before combustion in the chamber, the very cold fuel first passes through tiny channels in the walls of the engine nozzle, thereby continuously cooling it. You can see how it works in this animated diagram from Financial Times.

Tip: Watch a short video in which Tom Mueller of SpaceX explains how the Merlin engine works.

Merlin 1D was used for the first time in 2013 and is used on Falcon rockets to this day. A new feature compared to the previous Merlin 1C was the ability to throttle engine thrust down to 70% (and later to 56%). This is particularly useful when landing the first stage. Later, other enhancements have led to increased performance and reliability, and reduced manufacturing effort. Merlin 1D has never failed during a mission. The latest version of this engine, which has a slightly increased thrust and other improvements, is sometimes referred to as Merlin 1D Block 5 or even Merlin 1E.

Launch Profile and Landing Options

At launch, both Falcon Heavy side boosters are running at full thrust, while the center core is running at low thrust. After a few minutes, the side boosters separate, while the central stage, with the upper stage on top, keeps going (this time at full thrust) and then separates later. Recovery of all three boosters will likely be attempted for most missions, but there are several different landing options:

Standard Falcon Heavy mission profile

  1. Both side boosters land on land, while the central lands on droneship (since it goes much farther downrange and reaches much higher velocity). This method is likely to be the most common.
  2. All three boosters could land back on land in the case of missions to low orbits or with light payloads. An example of such a mission is STP-2. However, SpaceX has only two landing pads on land in Florida (LZ-1 and LZ-2), so in such cases the center core would land on a droneshop which would be positioned only a short distance from the coast (a few dozen kilometers instead of the usual 600–1000 km).
  3. For more demanding missions (heavy payload or high orbit), it’s possible for the side boosters to land on droneships in the ocean, while the center core would be expended. Elon Musk said that one of the reasons why SpaceX is working on a third droneship (called A Shortfall of Gravitas) was the potential need to land both side boosters at sea.
  4. On extremely demanding missions where maximum performance is needed (such as interplanetary launches), Falcon Heavy could launch in fully expendable mode. In this scenario, the rocket wouldn’t be equipped with landing hardware, would burn pretty much all its fuel to maximize performance, and then all three boosters would be expended and eventually destroyed by impacting the ocean’s surface.

Launch Pads

The first Falcon Heavy launch was initially planned from launch pad SLC-4E in California, but now it seems unlikely it will ever launch from that pad. It is unclear whether the pad was ever actually ready for Falcon Heavy launches, but it was designed for FH. For example, the transporter/erector (T/E) is large enough to accomodate Falcon Heavy. The pad infrastructure, however, was upgraded in 2016 in order to support subcooled propellants used by the new Falcon variant v1.2, but pad compatibility with Falcon Heavy was presumably not maintained when the upgrades were made. This is supported by the fact that the latest revision of the Falcon User’s Guide no longer offers Falcon Heavy launches from California.

Launch pad SLC-4E at Vandenberg Air Force Station in California (Credit: SpaceX)

Falcon Heavy eventually launched for the first time from Florida’s pad LC-39A at Kennedy Space Center. The first SpaceX launch from this pad took place in February 2017, but initially only the smaller Falcon 9 rocket could be launched from here. The pad’s construction became a priority after the nearby pad SLC-40 was destroyed in September 2016 during the Amos-6 anomaly. After SpaceX started using the completed pad LC-39A, additional work was still needed to make it compatible with Falcon Heavy. SpaceX did this work in between Falcon 9 launches during 2017.

Aerial view of pad 39A (Credit: Hope Geiger / Air National Guard)

On October 1, 2017, photos of the transporter/erector on pad ramp 39A appeared, showing two newly mounted FH side booster clamps. At the end of October, shots from Falcon 9’s roll-out seen during the live KoreaSat 5A webcast showed that the work progressed further and additional clamps were installed. The T/E modifications were probably completed in November, as the fully-assembled Falcon Heavy was mated to it by early December.

LC-39A is currently the only pad from which Falcon Heavy can launch, but the SpaceX pad that’s being built in South Texas near Boca Chica Village was also originally intended to launch Falcon 9 and Falcon Heavy rockets. However, plans have changed over the years, and SpaceX has decided that the Texas pad will be used primarily to launch the upcoming Super Heavy Starship.

Advantages Over Falcon 9

Falcon Heavy has triple the thrust of the smaller Falcon 9, and thus roughly three times the payload capacity. As a result, the rocket is capable of carrying payloads directly to geostationary orbit and still recover the boosters. Falcon 9 does not have enough performance for this.

Falcon rocket family

Falcon Heavy’s higher payload capacity also means satellites can be deployed to a higher than standard (supersynchronous) geostationary transfer orbit. That way, the customer saves time and money because the satellite reaches final geostationary orbit sooner and consumes less fuel, which can then be used to maintain orbit for longer, which actually extends the overall lifetime of the satellite. Although Falcon 9 can also launch a heavy satellite into a supersynchronous orbit, it’s usually only possible in expendable configuration (first stage is not recovered). However, boosters being expended are a waste of resources for SpaceX, and so it is better to use Falcon Heavy for such missions because it is capable of recovering of three boosters even after launching payloads to a supersynchronous orbit.

USAF Certification

In November 2017, SpaceX President and COO Gwynne Shotwell clarified the Falcon Heavy certification process for EELV military launches (later renamed to NSSL – National Security Space Launch). Three successful missions are needed (with two successes in a row). However, SpaceX was allowed to apply for the EELV contracts before completing the three launches. Falcon Heavy won its first such contract in June 2018 and another one in February 2019.

However, since Falcon Heavy still isn’t fully certified, SpaceX can’t actually fulfill those contracts yet. The three required launches need to be completed first. Falcon Heavy successfully completed the demonstration mission in February 2018, and if Arabsat 6A and STP-2 go well, SpaceX will then receive the Falcon Heavy certification.

Additionally, STP-2 will launch with reused side boosters and the data collected during the mission will inform the certification process that would eventually allow SpaceX to use flight-proven boosters on military launches.

Cancelled Plans and Features

Falcon 9 with mini-BFR on top – one of the concepts for a reusable Falcon upper stage that were considered (Credit: /u/purpleefilthh)

Falcon Heavy was originally supposed to use crossfeed, which is a way of distributing fuel across rocket stages during flight. This increases efficiency and hence performance and payload capacity. However, it is a challenging engineering problem and no such system has been developed yet. Eventually, SpaceX abandoned the idea of crossfeed, saying that if it’s ever needed in the future, the company might reconsider it.

For a long time, Elon Musk also considered the idea of ​​a reusable Falcon upper stage. He even said in March 2017 that SpaceX might attempt experimental recovery of the upper stage during the Falcon Heavy demonstration mission. However, that experiment never came to pass and Musk announced at the end of 2018 that Falcon rockets won’t be getting any more major upgrades (that means there are no plans for a reusable upper stage to be developed). SpaceX will instead focus on the development of fully-reusable Super Heavy Starship which is expected to evetually replace the Falcon rocket family anyway.

Falcon Heavy was also supposed to be capable of crewed flights. In February 2017, SpaceX announced that Falcon Heavy would send the Crew Dragon spacecraft around the moon and back. Later, however, the company changed this plan. In the fall of 2018, SpaceX announced that the private lunar flyby mission is called dearMoon and that it will be performed using BFR (now called Starship) instead of Falcon Heavy. SpaceX said that it will human-rate Falcon Heavy for crewed launches only if Super Heavy Starship development goes significantly slower than expected.

History of Falcon Heavy

The first mention of Falcon Heavy (formerly called Falcon 9 Heavy) dates back to 2005, even before the first launch of Falcon 1. In 2011, SpaceX had several Falcon 9 launches under its belt and therefore a better idea of ​​the planned Falcon Heavy. The company initially planned to launch the first Falcon Heavy from pad SLC-4E ramp in California but that never happened. The first launch from the East Coast (Cape Canaveral) was then planned for 2013 or 2014. The company also released a video in 2011 showing a Falcon Heavy based on the now outdated Falcon 9 v1.0 variant. Another video was released in January 2015 and depicted a much updated Falcon Heavy as we know it today, even showing all three boosters landing:

In March 2015, first signs of actual Falcon Heavy development appeared online. SpaceX published (and quickly deleted) photos of the Falcon Heavy scale model used for wind-tunnel testing:

In early 2016, Falcon Heavy nose cone was spotted in the background of a photo from SpaceX’s factory in Hawthorne. Then later, that same nose cone was spotted being transported out of Hawthorne.

At the end of 2016, SpaceX published a photo on the company’s official Instagram showing the rocket interstage with Falcon Heavy logo:

Falcon Heavy interstage in Hawthorne (Credit: SpaceX)

In the spring of 2017, Falcon Heavy boosters were spotted being transported from Hawthorne to McGregor where they were tested afterwards:

In May 2017, the center core and one of the side boosters were test fired in McGregor. The other side booster and the upper stage were test-fired in September. SpaceX released videos from the static fires:

In October 2017, the last remaining components arrived to LC-39A and by early December, the first Falcon Heavy was assembled in the HIF (Horizontal Integration Facility). Final tests of the fully-assembled rocket could then begin in preparation for the demonstration mission.

Demonstration Mission

Pre-flight Preparations

In December 2017, SpaceX released first photos of the assembled Falcon Heavy before and after the roll-out to pad 39A where a dry dress rehearsal was conducted. In January 2018, several wet dress rehearsals took place, which culminated in a successful static fire on January 24. It was the first time that all 27 Merlin engines were ignited at once (before that, boosters could only be test fired individually in McGregor).

Launch and Landing

The inaugural launch finally happened on February 6, 2018. Side boosters landed successfully and almost simultaneously on LZ-1 and LZ-2, but the center core landing on OCISLY failed because two of the rocket’s engines ran out of TEA-TEB, a pyrophoric ignition fluid, and therefore only one of three engines needed for the landing burn ignited. The booster crashed into water right next to OCISLY.

The side boosters were reused and previously launched on Thaicom-8 and CRS-9 missions . They were Falcon 9s numbered B1023 and B1025 of the v1.2 Block 2 variant (but according to unofficial information, the boosters were essentially upgraded to Block 3 during the refurbishment process). The center core was new (number B1033), and it was a Block 3. All future FHs will consist of boosters of the much improved Block 5 version. The side boosters on this launch had titanium grid fins while the center core had aluminum fins. The reason for this was the need for better maneuverability of the side boosters due to different aerodynamics (side boosters have nose cones instead of a flat interstage).

Tesla and Starman

Instead of a boring mass simulator, like a block of concrete, Elon Musk decided to use his own Tesla Roadster as the payload for this test launch. Behind the wheel was Starman, a dummy in a SpaceX spacesuit. The car spent several hours in orbit around Earth and then was successfully sent to a heliocentric orbit that reaches beyond Mars’ orbit around the Sun. According to Elon Musk, the Roadster will spend “a billion year” in space.

Mission Arabsat 6A

The second Falcon Heavy launch occured on April 11, 2019. It was the first flight of the upgraded Falcon Heavy Block 5 and also the rocket’s first commercial launch, carrying the Arabsat 6A satellite.

The mission was a success. The satellite was deployed in the correct supersynchronous geostationary transfer orbit, all three boosters landed successfully (first time for the center core). Both side boosters were then reused on the STP-2 mission. Even the fairings were recovered during the Arabsat launch and might be reused later.

However, the center core tipped over some time after landing, due to rough sea conditions. The rocket was heavily damaged and OCISLY came back to port with only the bottom section of the rocket. Elon Musk stated that the engines might still be reused.

Mission STP-2

The STP-2 mission was successfully completed on June 25, 2019, and according to SpaceX, it was the most challenging mission in the company’s history. The reason was that the payload consisted of USAF’s 24 satellites that had to be deployed into three different orbits in LEO and MEO. It took over three hours and required four separate burns of the upper-stage Merlin engine. The deployment was 100% successful and SpaceX also managed to softly land the side boosters on LZ-1 and LZ-2 and to catch the rocket’s fairing for the very first time, using the ship Ms. Tree (formerly Mr. Steven) equipped with a large net.

The only flaw in this otherwise perfect launch was the unsuccessful landing of the center core on OCISLY. Elon Musk explained that “high entry force & heat breached engine bay & center engine TVC failed”. TVC stands for Thrust Vector Control and without it the center engine, which is used during landing, was unable to steer the rocket and therefore crashed in the water next to OCISLY.

Past and Future Launches

Date (UTC) Mission Orbit Notes
Feb 6, 2018 FH Demo TMI Demonstration mission. Elon Musk’s Tesla Roadster served as the payload.
Apr 11, 2019 Arabsat 6A GTO First launch of FH Block 5. Carried a telecommunications satellite for Saudi Arabia.
June 25, 2019 STP-2 LEO/MEO Mission for USAF. 24 satellites were deployed to 3 different orbits.
2020 AFSPC-44 GEO NSSL contract
2021–2022 ViaSat-3 GEO Telecommunications satellite that will be launched into “a nearly geostationary orbit”
2021 AFSPC-52 GTO First competitively won NSSL contract

(More specific launch dates can be found on the Launch Manifest page.)

More Falcon Heavy Photos

Falcon Heavy Videos

Demo Mission Webcast:

Side Boosters Landing:

Falcon Heavy on Pad:

Falcon Heavy Going Vertical on Pad:

Demo Mission Animation:

Official Video Celebrating the Demo Mission:


Changelog:

  • August 23 – Ovzon-3 removed from the list of missions (will launch on Ariane 5)
  • June 27 – Added information and photos from the STP-2 launch + updated the mission manifest
  • April 21 – Added information and photos about the Arabsat center core mishap
  • April 14 – Added some basic information about Arabsat 6A launch (more details will be added later)
  • March 31 – Article first published

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