RL-10
Encyclopedia
The RL10 was USA's first liquid hydrogen fueled rocket engine. An updated version is used in several current launch vehicle
s. Six RL10 engines were used in the S-IV
second stage of the Saturn I
rocket. One or two RL10 engines are used in the Centaur
upper stages of Atlas and Titan
rockets. One RL10 is used in the upper stage of Delta IV rockets.
The first flight using production versions of the RL10 engine launched November 27, 1963. For that launch, two RL10A-3 engines powered the Centaur
upper stage of an Atlas
launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.
ing for reduced weight and increased reliability. Current specific impulse is 464 s (equivalent to an exhaust velocity of 4.55 km/s).
(66.7 kN)
Burn Time: 470 s
Design: Expander cycle
Specific impulse
: 433 s (4.25 kN·s/kg)
Engine weight - dry
: 298 lb (135 kg)
Height: 68 in (1.73 m)
Diameter: 39 in (0.99 m)
Nozzle expansion ratio: 40 to 1
Propellants: LOX & LH2
Propellant flow: 35 lb/s (16 kg/s)
Contractor: Pratt & Whitney
Vehicle application: Saturn I
/ S-IV
2nd stage - 6-engines
Vehicle application: Centaur
upper stage - 2-engines
RL10B-2 Specifications
A flaw in the brazing of an RL10B-2 combustion chamber was identified as the cause of failure for the Delta III launch carrying the Orion-3 communications satellite
.
RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on Centaur
upper stage for Atlas V
.
.
The DIRECT
version 3.0 proposal to replace Ares I
and Ares V
with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles. Up to seven (7) RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the Ares V
Earth Departure Stage
.
(LSAM) would be powered by liquid hydrogen and liquid oxygen. The original plan called for the ascent stage to use liquid methane and liquid oxygen, but that has changed and the ascent stage will now also use LH2/LOX.
Because of the choice of propellents, along with the need to land the spacecraft in the polar regions of the Moon from an equatorial orbit, NASA decided to use the RL10 as the main powerplant for the descent stage engine. Current specifications call for four RL10 engines to be used on the descent stage and a single RL10 for the ascent stage. Currently, the RL10B-2 engines used on the Delta III and Delta IV can thrust at 20% of maximum thrust. Because of the need for the LSAM to hover above the lunar surface, along with providing a smooth landing, the new RL10 engines must be able to thrust as low as 10%. The use of the RL10 will allow NASA to keep costs on the lunar program down by using existing hardware, albeit modified to enhance performance or allow for manned spaceflight.
to develop the CECE demonstrator engine. In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios. In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.
(ACES), a long-duration, low-boiloff extension of existing ULA
Centaur
and Delta Cryogenic Second Stage (DCSS) technology. Long-duration ACES technology is explicitly designed to support geosynchronous, cislunar, and interplanetary missions as well as provide in-space propellant depot
s in LEO or at that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or interplanetary missions. Additional missions could include the provision of the high-energy technical capacity for the cleanup of space debris
.
Launch vehicle
In spaceflight, a launch vehicle or carrier rocket is a rocket used to carry a payload from the Earth's surface into outer space. A launch system includes the launch vehicle, the launch pad and other infrastructure....
s. Six RL10 engines were used in the S-IV
S-IV
The S-IV was the second stage of the Saturn I, a rocket-powered launch vehicle used by NASA for early flights in the Apollo program.The S-IV was manufactured by the Douglas Aircraft Company and later modified by them to the S-IVB, a similar but distinct stage used on the Saturn IB and Saturn V...
second stage of the Saturn I
Saturn I
The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...
rocket. One or two RL10 engines are used in the Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
upper stages of Atlas and Titan
Titan (rocket family)
Titan was a family of U.S. expendable rockets used between 1959 and 2005. A total of 368 rockets of this family were launched, including all the Project Gemini manned flights of the mid-1960s...
rockets. One RL10 is used in the upper stage of Delta IV rockets.
History
The RL10 was first tested on the ground in 1959 and first flown in 1963.The first flight using production versions of the RL10 engine launched November 27, 1963. For that launch, two RL10A-3 engines powered the Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
upper stage of an Atlas
Atlas (rocket family)
Atlas is a family of U.S. space launch vehicles. The original Atlas missile was designed in the late 1950s and produced by the Convair Division of General Dynamics, to be used as an intercontinental ballistic missile...
launch vehicle. The launch was used to conduct a heavily instrumented performance and structural integrity test of the vehicle.
Improvements
The RL10 has been upgraded over the years. One current model, the RL10B-2, powers the Delta IV second stage, as well as the Delta III second stage. It has been significantly modified from the original RL10 to improve performance. Some of the enhancements include an extendable nozzle and electro-mechanical gimbalGimbal
A gimbal is a pivoted support that allows the rotation of an object about a single axis. A set of two gimbals, one mounted on the other with pivot axes orthogonal, may be used to allow an object mounted on the innermost gimbal to remain immobile regardless of the motion of its support...
ing for reduced weight and increased reliability. Current specific impulse is 464 s (equivalent to an exhaust velocity of 4.55 km/s).
Original RL10
Thrust (altitude): 15,000 lbfPound-force
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...
(66.7 kN)
Burn Time: 470 s
Design: Expander cycle
Expander cycle (rocket)
The expander cycle is a power cycle of a bipropellant rocket engine meant to improve the efficiency of fuel delivery.In an expander cycle, the fuel is heated before it is combusted, usually with waste heat from the main combustion chamber. As the liquid fuel passes through coolant passages in the...
Specific impulse
Specific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
: 433 s (4.25 kN·s/kg)
Engine weight - dry
Dry weight
Dry weight is the weight of a vehicle without any consumables, passengers, or cargo.It is one of the two common weight measurements included in road vehicle specifications, the other one being curb weight....
: 298 lb (135 kg)
Height: 68 in (1.73 m)
Diameter: 39 in (0.99 m)
Nozzle expansion ratio: 40 to 1
Propellants: LOX & LH2
Propellant flow: 35 lb/s (16 kg/s)
Contractor: Pratt & Whitney
Vehicle application: Saturn I
Saturn I
The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...
/ S-IV
S-IV
The S-IV was the second stage of the Saturn I, a rocket-powered launch vehicle used by NASA for early flights in the Apollo program.The S-IV was manufactured by the Douglas Aircraft Company and later modified by them to the S-IVB, a similar but distinct stage used on the Saturn IB and Saturn V...
2nd stage - 6-engines
Vehicle application: Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
upper stage - 2-engines
Current design
- Thrust (altitude): 24,750 lbf (110.1 kN)
- Design: Expander cycle
- Burn time: 1,152 seconds
- Specific impulseSpecific impulseSpecific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
: 464 s (4.55 kN·s/kg) - Engine weight - dry: 610 lb (277 kg)
- Height: 163 in (4.14 m)
- Diameter: 87 in (2.21 m)
- Expansion ratioExpansion ratioThe expansion ratio of a liquefied and cryogenic substance is the volume of a given amount of that substance in liquid form compared to the volume of the same amount of substance in gaseous form, at a given temperature and pressure....
: 250 to 1 - Mixture ratio: 5.85 to 1
- Propellants: Liquid oxygenLiquid oxygenLiquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
& liquid hydrogenLiquid hydrogenLiquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecular H2 form.To exist as a liquid, H2 must be pressurized above and cooled below hydrogen's Critical point. However, for hydrogen to be in a full liquid state without boiling off, it needs to be... - Propellant flow: Oxidizer 41.42 lb/s (20.6 kg/s), fuel 7.72 lb/s (3.5 kg/s)
- Contractor: Pratt & Whitney
- Vehicle application: Delta IIIDelta III rocketThe Delta III rocket was an expendable launch vehicle made by Boeing. The first Delta III launch was on August 26, 1998. Of its three flights, the first two were failures, and the third, though declared successful, reached the low end of its targeted orbit range and carried only a dummy payload...
, Delta IV second stage (1 engine)
A flaw in the brazing of an RL10B-2 combustion chamber was identified as the cause of failure for the Delta III launch carrying the Orion-3 communications satellite
Communications satellite
A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...
.
RL10A-4-2
The other current model, the RL10A-4-2, is the engine used on Centaur
Centaur
In Greek mythology, a centaur or hippocentaur is a member of a composite race of creatures, part human and part horse...
upper stage for Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
.
Other rockets using RL10
Four modified RL10A-5 engines, all of them with the ability to be throttled, were used in the McDonnell Douglas DC-XMcDonnell Douglas DC-X
The DC-X, short for Delta Clipper or Delta Clipper Experimental, was an unmanned prototype of a reusable single stage to orbit launch vehicle built by McDonnell Douglas in conjunction with the United States Department of Defense's Strategic Defense Initiative Organization from 1991 to 1993...
.
The DIRECT
DIRECT
DIRECT is a proposed alternative heavy lift launch vehicle architecture supporting NASA's Vision for Space Exploration, which would replace the space agency's planned Ares I and Ares V rockets...
version 3.0 proposal to replace Ares I
Ares I
Ares I was the crew launch vehicle that was being developed by NASA as part of the Constellation Program. The name "Ares" refers to the Greek deity Ares, who is identified with the Roman god Mars...
and Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
with a family of rockets sharing a common core stage, recommends the RL10 for the second stage of their proposed J-246 and J-247 launch vehicles. Up to seven (7) RL10 engines would be used in the proposed Jupiter Upper Stage, serving an equivalent role to the Ares V
Ares V
The Ares V was the planned cargo launch component of the Constellation program, which was to have replaced the Space Shuttle after its retirement in 2011. Ares V was also planned to carry supplies for a human presence on Mars...
Earth Departure Stage
Earth Departure Stage
The Ares V Earth Departure Stage was a rocket stage which NASA planned to design at its Marshall Space Flight Center in Huntsville, Alabama as part of Project Constellation...
.
Future use of the RL10
Several potential uses of enhanced versions of the RL10 engine have been proposed:Manned lunar missions
In 2005 NASA announced the decision to use an Apollo-like spacecraft configuration for the proposed Orion spacecraft. At that time NASA decided that the descent stage of the new Lunar Surface Access ModuleLunar Surface Access Module
The Altair spacecraft, previously known as the Lunar Surface Access Module or LSAM, was the planned lander spacecraft component of NASA's cancelled Project Constellation. Astronauts would have used the spacecraft for landings on the Moon, which had been intended to begin around 2019...
(LSAM) would be powered by liquid hydrogen and liquid oxygen. The original plan called for the ascent stage to use liquid methane and liquid oxygen, but that has changed and the ascent stage will now also use LH2/LOX.
Because of the choice of propellents, along with the need to land the spacecraft in the polar regions of the Moon from an equatorial orbit, NASA decided to use the RL10 as the main powerplant for the descent stage engine. Current specifications call for four RL10 engines to be used on the descent stage and a single RL10 for the ascent stage. Currently, the RL10B-2 engines used on the Delta III and Delta IV can thrust at 20% of maximum thrust. Because of the need for the LSAM to hover above the lunar surface, along with providing a smooth landing, the new RL10 engines must be able to thrust as low as 10%. The use of the RL10 will allow NASA to keep costs on the lunar program down by using existing hardware, albeit modified to enhance performance or allow for manned spaceflight.
Common Extensible Cryogenic Engine
The Common Extensible Cryogenic Engine (CECE) is a testbed to develop RL10 engines that throttle well. NASA has contracted with Pratt & Whitney RocketdynePratt & Whitney Rocketdyne
Pratt & Whitney Rocketdyne is a United States company that designs and produces rocket engines that use liquid propellants. Pratt & Whitney Rocketdyne, headquartered in Canoga Park, California, is a division of Pratt & Whitney, itself a wholly owned subsidiary of United Technologies Corporation...
to develop the CECE demonstrator engine. In 2007 its operability (with some "chugging") was demonstrated at 11-to-1 throttle ratios. In 2009 NASA reported successfully throttling from 104 percent thrust to eight percent thrust, a record for an engine of this type. Chugging was eliminated by injector and propellant feed system modifications that control the pressure, temperature and flow of propellants.
Advanced Common Evolved Stage
, an enhanced version of the RL10 rocket engine was proposed to power the upper-stage versions of the Advanced Common Evolved StageAdvanced Common Evolved Stage
The Advanced Common Evolved Stage, or ACES, is a proposed upper stage rocket for use on space launch vehicles. The design concept is from the U.S. company United Launch Alliance . ACES is intended to boost satellite payloads to geosynchronous orbit or, in the case of an interplanetary space...
(ACES), a long-duration, low-boiloff extension of existing ULA
United Launch Alliance
United Launch Alliance is a joint venture of Lockheed Martin and Boeing. ULA was formed in December 2006 by combining the teams at these companies which provide spacecraft launch services to the government of the United States. U.S...
Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
and Delta Cryogenic Second Stage (DCSS) technology. Long-duration ACES technology is explicitly designed to support geosynchronous, cislunar, and interplanetary missions as well as provide in-space propellant depot
Propellant depot
An orbital propellant depot is a cache of propellant that is placed on an orbit about the Earth or another body to allow spacecraft to be fuelled in space. Launching a spacecraft separately from some of its propellant enables missions with more massive payloads...
s in LEO or at that could be used as way-stations for other rockets to stop and refuel on the way to beyond-LEO or interplanetary missions. Additional missions could include the provision of the high-energy technical capacity for the cleanup of space debris
Space debris
Space debris, also known as orbital debris, space junk, and space waste, is the collection of objects in orbit around Earth that were created by humans but no longer serve any useful purpose. These objects consist of everything from spent rocket stages and defunct satellites to erosion, explosion...
.
See also
- Spacecraft propulsionSpacecraft propulsionSpacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
- RD-0146RD-0146The RD-0146 is a Russian cryogenic rocket engine. It is said to be the Russian version of the Pratt & Whitney Rocketdyne RL10 engine. The RD-0146 engine was developed by KBKhA design bureau in Voronezh, Russia, in cooperation with the American Pratt & Whitney Rocketdyne company...
- XCOR/ULA aluminum alloy nozzle engine, under development in 2011 ff.