The F-1 is a

rocket engine A rocket engine is a reaction engine, producing thrust in accordance with Newton's third law by ejecting reaction mass rearward, usually a high-speed Jet (fluid), jet of high-temperature gas produced by the combustion of rocket propellants stor ...

developed by Rocketdyne. The engine uses a gas-generator cycle developed in the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

in the late 1950s and was used in the Saturn V rocket in the 1960s and early 1970s. Five F-1 engines were used in the S-IC first stage of each Saturn V, which served as the main launch vehicle of the

Apollo program The Apollo program, also known as Project Apollo, was the United States human spaceflight program led by NASA, which Moon landing, landed the first humans on the Moon in 1969. Apollo followed Project Mercury that put the first Americans in sp ...

. The F-1 remains the most powerful single combustion chamber

liquid-propellant rocket A liquid-propellant rocket or liquid rocket uses a rocket engine burning liquid rocket propellant, liquid propellants. (Alternate approaches use gaseous or Solid-propellant rocket , solid propellants.) Liquids are desirable propellants because th ...

engine ever developed.

History

Rocketdyne developed the F-1 and the E-1 to meet a 1955 U.S. Air Force requirement for a very large rocket engine. The E-1, although successfully tested in static firing, was quickly seen as a technological dead-end, and was abandoned for the larger, more powerful F-1. The Air Force eventually halted development of the F-1 because of a lack of requirement for such a large engine. However, the recently created National Aeronautics and Space Administration (NASA) appreciated the usefulness of an engine with so much power and contracted Rocketdyne to complete its development. Test firings of F-1 components had been performed as early as 1957. The first static firing of a full-stage developmental F-1 was performed in March 1959. The first F-1 was delivered to NASA MSFC in October 1963. In December 1964, the F-1 completed flight rating tests. Testing continued at least through 1965. Early development tests revealed serious combustion instability problems which sometimes caused catastrophic failure. Initially, progress on this problem was slow, as it was intermittent and unpredictable. Oscillations of 4 kHz with harmonics to 24 kHz were observed. Eventually, engineers developed a diagnostic technique of detonating small explosive charges (which they called "bombs") outside the combustion chamber, through a tangential tube ( RDX, C-4 or

black powder Gunpowder, also commonly known as black powder to distinguish it from modern smokeless powder, is the earliest known chemical explosive. It consists of a mixture of sulfur, charcoal (which is mostly carbon), and potassium nitrate, potassium ni ...

were used) while the engine was firing. This allowed them to determine exactly how the running chamber responded to variations in pressure, and to determine how to nullify these oscillations. The designers could then quickly experiment with different co-axial fuel-injector designs to obtain the one most resistant to instability. These problems were addressed from 1959 through 1961. Eventually, engine combustion was so stable, it would self-damp artificially induced instability within one-tenth of a second.

Design

The F-1 engine is the most powerful single-nozzle liquid-fueled rocket engine ever flown. The M-1 rocket engine was designed to have more thrust, but it was only tested at the component level. The later developed RD-170 is much more stable, technologically more advanced, more efficient and produces more thrust, but uses four nozzles fed by a single pump. The F-1 burned

RP-1 RP-1 (Rocket Propellant-1 or Refined Petroleum-1) and similar fuels like RG-1 and T-1 are highly refined kerosene formulations used as rocket fuel. Liquid-fueled rockets that use RP-1 as fuel are known as kerolox rockets. In their engines, RP- ...

(rocket grade kerosene) as the fuel and used liquid oxygen (LOX) as the oxidizer. A turbopump was used to inject fuel and oxygen into the combustion chamber. One notable challenge in the construction of the F-1 was regenerative cooling of the thrust chamber. Chemical engineer Dennis "Dan" Brevik was faced with the task of ensuring the preliminary combustion chamber tube bundle and manifold design produced by Al Bokstellar would run cool. In essence, Brevik's job was to "make sure it doesn’t melt." Through Brevik's calculations of the hydrodynamic and thermodynamic characteristics of the F-1, he and his team were able to fix an issue known as ‘starvation’. This is when an imbalance of static pressure leads to 'hot spots' in the manifolds. The material used for the F-1 thrust chamber tube bundle, reinforcing bands and manifold was Inconel-X750, a refractory nickel based alloy capable of withstanding high temperatures. The heart of the engine was the thrust chamber, which mixed and burned the fuel and oxidizer to produce thrust. A domed chamber at the top of the engine served as a manifold supplying liquid oxygen to the injectors, and also served as a mount for the gimbal bearing which transmitted the thrust to the body of the rocket. Below this dome were the injectors, which directed fuel and oxidizer into the thrust chamber in a way designed to promote mixing and combustion. Fuel was supplied to the injectors from a separate manifold; some of the fuel first traveled in 178 tubes down the length of the thrust chamber — which formed approximately the upper half of the exhaust nozzle — and back in order to cool the nozzle. A gas generator was used to drive a

turbine A turbine ( or ) (from the Greek , ''tyrbē'', or Latin ''turbo'', meaning vortex) is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced can be used for generating electrical ...

which drove separate fuel and oxygen pumps, each feeding the thrust chamber assembly. The turbine was driven at 5,500 RPM, producing . The fuel pump delivered of RP-1 per minute while the oxidizer pump delivered of liquid oxygen per minute. Environmentally, the turbopump was required to withstand temperatures ranging from input gas at to liquid oxygen at . Structurally, fuel was used to lubricate and cool the turbine bearings. F-1 Engine Test Firing

Below the thrust chamber was the nozzle extension, roughly half the length of the engine. This extension increased the expansion ratio of the engine from 10:1 to 16:1. The exhaust from the turbine was fed into the nozzle extension by a large, tapered manifold; this relatively cool gas formed a film which protected the nozzle extension from the hot () exhaust gas. Each second, a single F-1 burned of oxidizer and fuel: of liquid oxygen and of RP-1, generating of thrust. This equated to a flow rate of per second; of LOX and of RP-1. During their two and a half minutes of operation, the five F-1s propelled the Saturn V vehicle to a height of and a speed of . The combined flow rate of the five F-1s in the Saturn V was or per second. Each F-1 engine had more thrust than three Space Shuttle Main Engines combined.

Pre and post ignition procedures

During static test firing, the kerosene-based RP-1 fuel left

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ...

deposits and vapors in the engine post test firing. These had to be removed from the engine to avoid problems during engine handling and future firing, and the solvent trichloroethylene (TCE) was used to clean the engine's fuel system immediately before and after each test firing. The cleaning procedure involved pumping TCE through the engine's fuel system and letting the solvent overflow for a period ranging from several seconds to 30–35 minutes, depending upon the engine and the severity of the deposits. Sometimes the engine's gas generator and LOX dome were also flushed with TCE prior to test firing. The F-1 rocket engine had its LOX dome, gas generator, and thrust chamber fuel jacket flushed with TCE during launch preparations.

Specifications

Sources:

F-1 improvements

F-1 rocket engine at United States Space and Rocket Center in 2006

F-1 thrust and efficiency were improved between

Apollo 8 Apollo 8 (December 21–27, 1968) was the first crewed spacecraft to leave Sphere of influence (astrodynamics), Earth's gravitational sphere of influence, and the first human spaceflight to reach the Moon. The crew orbited the Moon ten times ...

(SA-503) and

Apollo 17 Apollo 17 (December 7–19, 1972) was the eleventh and final mission of NASA's Apollo program, the sixth and most recent time humans have set foot on the Moon. Commander Gene Cernan and Lunar Module Pilot Harrison Schmitt walked on the Moon, ...

(SA-512), which was necessary to meet the increasing payload capacity demands of later

Apollo Apollo is one of the Twelve Olympians, Olympian deities in Ancient Greek religion, ancient Greek and Ancient Roman religion, Roman religion and Greek mythology, Greek and Roman mythology. Apollo has been recognized as a god of archery, mu ...

missions. There were small performance variations between engines on a given mission, and variations in average thrust between missions. For

Apollo 15 Apollo 15 (July 26August 7, 1971) was the ninth crewed mission in the Apollo program and the fourth Moon landing. It was the first List of Apollo missions#Alphabetical mission types, J mission, with a longer stay on the Moon and a greate ...

, F-1 performance was: *Thrust (average, per engine, sea level liftoff): *Burn time: 159 seconds *

Specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

: *Mixture ratio: 2.2674 * S-IC total sea level liftoff thrust: Measuring and making comparisons of rocket engine thrust is more complicated than it may first appear. Based on actual measurement the liftoff thrust of

was , which equates to an average F-1 thrust of – slightly more than the specified value.

F-1A after Apollo

During the 1960s, Rocketdyne undertook uprating development of the F-1 resulting in the new engine specification F-1A. While outwardly very similar to the F-1, the F-1A produced about 20% greater thrust, in tests, and would have been used on future Saturn V vehicles in the post-

era. However, the Saturn V production line was closed prior to the end of Project Apollo and no F-1A engines ever flew. There were proposals to use eight F-1 engines on the first stage of the Saturn C-8 and Nova rockets. Numerous proposals have been made from the 1970s and on to develop new expendable boosters based around the F-1 engine design. These include the Saturn-Shuttle, and the Pyrios booster (see below) in 2013. , none have proceeded beyond the initial study phase. The Comet HLLV would have used five F-1A engines on the main core and two on each of the boosters. The F-1 is the largest, highest-thrust single-chamber, single-nozzle liquid-fuel engine flown. Larger solid-fuel engines exist, such as the Space Shuttle Solid Rocket Booster with a sea-level liftoff thrust of apiece. The Soviet (now Russian) RD-170 can develop more thrust than the F-1, at per engine at sea level, however, each engine uses four combustion chambers instead of one, to solve the combustion instability problem.

F-1B booster

As part of the Space Launch System (SLS) program, NASA had been running the Advanced Booster Competition, which was scheduled to end with the selection of a winning booster configuration in 2015. In 2013, engineers at the Marshall Space Flight Center began tests with an original F-1, serial number F-6049, which was removed from Apollo 11 due to a glitch. The engine was never used, and for many years it was at the

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. The tests are designed to refamiliarize NASA with the design and propellants of the F-1 in anticipation of using an evolved version of the engine in future deep-space flight applications. In 2012, Pratt & Whitney, Rocketdyne, and Dynetics, Inc. presented a competitor known as Pyrios, a liquid rocket booster, in NASA's Advanced Booster Program, which aims to find a more powerful successor to the five-segment Space Shuttle Solid Rocket Boosters intended for early versions of the Space Launch System. Pyrios uses two increased-thrust and heavily modified F-1B engines per booster. Due to the engine's potential advantage in

specific impulse Specific impulse (usually abbreviated ) is a measure of how efficiently a reaction mass engine, such as a rocket engine, rocket using propellant or a jet engine using fuel, generates thrust. In general, this is a ratio of the ''Impulse (physics), ...

, if this F-1B configuration (using four F-1Bs in total) were integrated with the SLS Block 2, the vehicle could deliver to

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

, while is what is regarded as achievable with the planned solid boosters combined with a four-engine RS-25 core stage. The F-1B engine has a design goal to be at least as powerful as the unflown F-1A, while also being more cost effective. The design incorporates a greatly simplified combustion chamber, a reduced number of engine parts, and the removal of the F-1 exhaust recycling system, including the turbine exhaust mid-nozzle and the "curtain" cooling manifold, with the turbine exhaust having a separate outlet passage beside the shortened main nozzle on the F-1B. The reduction in parts costs is aided by using

selective laser melting Selective laser melting (SLM) is one of many proprietary names for a metal Additive Manufacturing, additive manufacturing (AM) technology that uses a bed of powder with a source of heat to create metal parts. Also known as direct metal laser sin ...

in the production of some metallic parts. The resulting F-1B engine is intended to produce of thrust at sea level, a 15% increase over the approximate of thrust that the mature

F-1 engines produced.

Locations of F-1 engines

Sixty-five F-1 engines were launched aboard thirteen Saturn Vs, and each first stage landed in the Atlantic Ocean. Ten of these followed approximately the same flight

azimuth An azimuth (; from ) is the horizontal angle from a cardinal direction, most commonly north, in a local or observer-centric spherical coordinate system. Mathematically, the relative position vector from an observer ( origin) to a point ...

of 72 degrees, but

and

followed significantly more southerly azimuths (80.088 degrees and 91.503 degrees, respectively). The Skylab launch vehicle flew at a more northerly azimuth to reach a higher inclination orbit (50 degrees versus the usual 32.5 degrees). Ten F-1 engines were installed on two production Saturn Vs that never flew. The first stage from SA-514 is on display at the Johnson Space Center in

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(although owned by the Smithsonian) and the first stage from SA-515 is on display at the INFINITY Science Center at John C. Stennis Space Center in Mississippi. Another ten engines were installed on two ground-test Saturn Vs never intended to fly. The S-IC-T "All Systems Test Stage," a ground-test replica, is on display as the first stage of a complete Saturn V at the

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in Florida. SA-500D, the Dynamic Test Vehicle, is on display at the U.S. Space and Rocket Center in

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. A test engine is on display at the

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. It was the 25th out of 114 research and development engines built by Rocketdyne and it was fired 35 times. The engine is on loan to the museum from the Smithsonian's National Air and Space Museum. It is the only F-1 on display outside the United States. An F-1 engine, on loan from the National Air and Space Museum, is on display at the Air Zoo in Portage, Michigan. An F-1 engine is on a horizontal display stand at Science Museum Oklahoma in

Oklahoma City Oklahoma City (), officially the City of Oklahoma City, and often shortened to OKC, is the List of capitals in the United States, capital and List of municipalities in Oklahoma, most populous city of the U.S. state of Oklahoma. The county seat ...

. F-1 engine F-6049 is displayed vertically at the Museum of Flight in

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as part of the Apollo exhibit. An F-1 engine is installed vertically as a memorial to the Rocketdyne builders on De Soto Avenue, across the street from the former Rocketdyne plant in Canoga Park, California. It was installed in 1979, and moved from the parking lot across the street some time after 1980. An F-1 Engine is on display outside of The New Mexico Museum of Space History in Alamogordo, New Mexico. A recovered F-1 thrust chamber is on display at the Cosmosphere. An intact engine (without nozzle extension) is displayed outdoors.

Recovery

On March 28, 2012, a team funded by Jeff Bezos, founder of Amazon.com, reported that they had located the F-1 rocket engines from an Apollo mission using sonar equipment. Bezos stated he planned to raise at least one of the engines, which rest at a depth of , about east of Cape Canaveral, Florida. However, the condition of the engines, which had been submerged for more than 40 years, was unknown. NASA Administrator Charles Bolden released a statement congratulating Bezos and his team for their find and wished them success. He also affirmed NASA's position that any recovered artifacts would remain property of the agency, but that they would likely be offered to the

and other museums, depending on the number recovered. On March 20, 2013, Bezos announced he had succeeded in bringing parts of an F-1 engine to the surface, and released photographs. Bezos noted, "Many of the original serial numbers are missing or partially missing, which is going to make mission identification difficult. We might see more during restoration."Walker, Brian (March 20, 2013)
"Apollo Mission Rocket Engines Recovered"
, CNN ''Light Years'' blog The recovery ship was '' Seabed Worker'', and had on board a team of specialists organized by Bezos for the recovery effort. On July 19, 2013, Bezos revealed that the serial number of one of the recovered engines is Rocketdyne serial number 2044 (equating to NASA number 6044), the #5 (center) engine that helped Neil Armstrong, Buzz Aldrin, and Michael Collins to reach the Moon with the

Apollo 11 Apollo 11 was a spaceflight conducted from July 16 to 24, 1969, by the United States and launched by NASA. It marked the first time that humans Moon landing, landed on the Moon. Commander Neil Armstrong and Lunar Module pilot Buzz Aldrin l ...

mission."Updates: 19 July 2013"
, Bezos Expeditions, July 19, 2013, accessed July 21, 2013. The recovered parts were brought to the Kansas Cosmosphere and Space Center in Hutchinson for the process of conservation. In August 2014, it was revealed that parts of two different F-1 engines were recovered, one from Apollo 11 and one from another Apollo flight, while a photograph of a cleaned-up engine was released. Bezos plans to put the engines on display at various places, including the National Air and Space Museum in Washington, D.C. On May 20, 2017, the Apollo permanent exhibit opened at the Museum of Flight in Seattle, WA and displays engine artifacts recovered including the thrust chamber and thrust chamber injector of the number 3 engine from the Apollo 12 mission, as well as a gas generator from an engine that powered the Apollo 16 flight.

References

External links

* ttps://web.archive.org/web/20161210045811/http://www.christophermadsen.com/docs/19750070175_1975070175.pdf F-1 Engine Operating Instructions(310MB)
The Saturn V F-1 Engine: Powering Apollo into History
at Springer.com
Remembering The Giants: Apollo Rocket Propulsion Development
2009, John C. Stennis Space Center. Monograph in Aerospace History No. 45 NASA
How NASA brought the monstrous F-1 “moon rocket” engine back to life

New F-1B rocket engine upgrades Apollo-era design with 1.8M lbs of thrust

MSFC History office F-1 Fact sheet

Anthony Young Collection, The University of Alabama in Huntsville Archives and Special Collections
Research material on the development of the F-1 engine. * U.S. Space & Rocket Center: . {{DEFAULTSORT:F-1 (Rocket Engine) Rocket engines using kerosene propellant Rocketdyne engines North American Aviation Rocket engines using the gas-generator cycle Rocket engines of the United States