Heavy lift launch vehicle
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A Heavy Lift Launch Vehicle, or HLV / HLLV, is a launch vehicle capable of lifting more mass into low Earth orbit (LEO) than Medium Lift[clarification needed] or Mid-Heavy Lift[clarification needed] 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. The Ariane 5 launcher is described by its operator Arianespace as a heavy lifter. The three-core configuration of the Atlas V launch vehicle family is also referred to as an HLV by its operator ULA. It is being offered, but to date this configuration has never flown. The very similar three-core configuration of ULA's other EELV launch vehicle, the Delta IV Heavy has similar performance. All the lauch vehicles mentioned here can lift 20,000 kg or more to low Earth orbit.
Several different fuel/oxidiser combinations have been used in heavy lift launch vehicles. The earliest ones were simply liquid hydrogen and liquid oxygen, which, when combined, release a very significant[clarification needed] amount of energy, 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 propellant 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 V first stage or in both the main and upper stages of the Falcon Heavy, and hypergolic propellants, such as unsymmetrical dimethylhydrazine and nitrogen tetroxide, used in the Proton rocket.
- HSF Final Report: Seeking a Human Spaceflight Program Worthy of a Great Nation, October 2009, Review of U.S. Human Spaceflight Plans Committee, p. 64-66: "5.2.1 The Need for Heavy Lift ... require a “super heavy-lift” launch vehicle ... range of 25 to 40 mt, setting a notional lower limit on the size of the super heavy-lift launch vehicle if refueling is available ... this strongly favors a minimum heavy-lift capacity of roughly 50 mt ..."
- "US co. SpaceX to build heavy-lift, low-cost rocket". Reuters. 5 April 2011. Archived from the original on 5 April 2011. Retrieved 6 April 2011. "Falcon Heavy can put about 117,000 pounds (53,071 kg) into orbit, twice the shuttle's 50,000-pound (22,680-kg) lift capability."
- Mallove, Eugene F. and Matloff, Gregory L. The Starflight Handbook: A Pioneer's Guide to Interstellar Travel, Wiley. ISBN 0-471-61912-4.