Heavy Lift Launch Vehicle
Encyclopedia
A Heavy Lift Launch Vehicle, or HLLV, is a launch vehicle
capable of lifting more mass into Low Earth Orbit
(LEO) than Medium Lift or Mid-Heavy Lift Launch Vehicles.
There is no universally accepted capability requirements for heavy-lift launch vehicles.
The minimum threshold for Super Heavy Lift Vehicles defined in the Augustine report
of 2009 is 50,000 kg to low-Earth orbit
.
and liquid oxygen
, which, when combined, produces a very significant amount of thrust, and whose only combustion byproducts are heat and water vapor
. This approach was used for the main engines of the Space Shuttle
and for the upper stages of the Saturn V
, and is still used for the main engines on some HLLVs, such as the Ariane 5 and Delta IV. It is also often used for upper-stage motors, due to its high specific impulse
.
Other fuel options include those used by solid-fuel rockets,
combinations of various liquid fuels such as RP-1
and liquid oxygen as used in the Atlas 5 first stage
or in both the main and upper stages of the Falcon Heavy
,
and hypergolic fuels, such as unsymmetrical dimethyl hydrazine
and nitrogen tetroxide, used in the Proton rocket
.
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....
capable of lifting more mass into Low Earth Orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
(LEO) than Medium Lift or Mid-Heavy Lift Launch Vehicles.
There is no universally accepted capability requirements for heavy-lift launch vehicles.
The minimum threshold for Super Heavy Lift Vehicles defined in the Augustine report
Review of United States Human Space Flight Plans Committee
The Review of United States Human Space Flight Plans Committee was a group reviewing the human spaceflight plans of the United States...
of 2009 is 50,000 kg to low-Earth orbit
Low Earth orbit
A low Earth orbit is generally defined as an orbit within the locus extending from the Earth’s surface up to an altitude of 2,000 km...
.
Fuel requirements
Several different fuel combinations have been used in heavy lift launch vehicles. The earliest ones were simply liquid hydrogenLiquid hydrogen
Liquid 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...
and liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
, which, when combined, produces a very significant amount of thrust, and whose only combustion byproducts are heat and water vapor
Water vapor
Water vapor or water vapour , also aqueous vapor, is the gas phase of water. It is one state of water within the hydrosphere. Water vapor can be produced from the evaporation or boiling of liquid water or from the sublimation of ice. Under typical atmospheric conditions, water vapor is continuously...
. This approach was used for the main engines of the Space Shuttle
Space Shuttle
The Space Shuttle was a manned orbital rocket and spacecraft system operated by NASA on 135 missions from 1981 to 2011. The system combined rocket launch, orbital spacecraft, and re-entry spaceplane with modular add-ons...
and for the upper stages of the Saturn V
Saturn V
The Saturn V was an American human-rated expendable rocket used by NASA's Apollo and Skylab programs from 1967 until 1973. A multistage liquid-fueled launch vehicle, NASA launched 13 Saturn Vs from the Kennedy Space Center, Florida with no loss of crew or payload...
, and is still used for the main engines on some HLLVs, such as the Ariane 5 and Delta IV. It is also often used for upper-stage motors, due to its high 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 ,...
.
Other fuel options include those used by solid-fuel rockets,
combinations of various liquid fuels such as RP-1
RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...
and liquid oxygen as used in the Atlas 5 first stage
or in both the main and upper stages of the Falcon Heavy
Falcon Heavy
Falcon Heavy, previously known as the Falcon 9 Heavy, is a spaceflight launch system that uses rocket engines currently being designed and manufactured by SpaceX. Both stages of the two-stage-to-orbit vehicles use liquid oxygen and rocket-grade kerosene propellants...
,
and hypergolic fuels, such as unsymmetrical dimethyl hydrazine
Dimethyl hydrazine
Dimethylhydrazine is the name of two compounds with the molecular formula C2H8N2. These are:* unsymmetrical dimethylhydrazine or 1,1-dimethylhydrazine, with both methyl groups are bonded to the same nitrogen atom...
and nitrogen tetroxide, used in the Proton rocket
Proton rocket
Proton is an expendable launch system used for both commercial and Russian government space launches. The first Proton rocket was launched in 1965 and the launch system is still in use as of 2011, which makes it one of the most successful heavy boosters in the history of spaceflight...
.
Further reading
- Mallove, Eugene F. and Matloff, Gregory L. The Starflight Handbook: A Pioneer's Guide to Interstellar Travel, Wiley. ISBN 0-471-61912-4.