§ 420.5 Definitions. For the purpose of this part. *Ballistic coefficient* means the weight of an object divided by the quantity product of the coefficient of drag of the object and the area of the object.
*Compatibility* means the chemical property of materials that may be located together without increasing the probability of an accident or, for a given quantity, the magnitude of the effects of such an accident.
*Debris dispersion radius* (Dmax) means the estimated maximum distance from a launch point that debris travels given a worst-case launch vehicle failure and flight termination early in flight. For an expendable launch vehicle, flight termination is assumed to occur at 10 seconds into flight.
*Downrange area* means a portion of a flight corridor beginning where a launch area ends and ending 5,000 nautical miles from the launch point, or where the IIP leaves the surface of the Earth, whichever is shorter, for an orbital launch vehicle; and ending with an impact dispersion area for a guided sub-orbital launch vehicle.
*E,F,G coordinate system* means an orthogonal, Earth-fixed, geocentric, right-handed system. The origin of the coordinate system is at the center of an ellipsoidal Earth model. The E-axis is positive directed through the Greenwich meridian. The F-axis is positive directed though 90 degrees east longitude. The EF-plane is coincident with the ellipsoidal Earth model's equatorial plane. The G-axis is normal to the EF-plane and positive directed through the north pole.
*E,N,U coordinate system* means an orthogonal, Earth-fixed, topocentric, right-handed system. The origin of the coordinate system is at a launch point. The E-axis is positive directed east. The N-axis is positive directed north. The EN-plane is tangent to an ellipsoidal Earth model's surface at the origin and perpendicular to the geodetic vertical. The U-axis is normal to the EN-plane and positive directed away from the Earth.
Effective casualty area (A c ) means the aggregate casualty area of each piece of debris created by a launch vehicle failure at a particular point on its trajectory. The effective casualty area for each piece of debris is the area within which 100 percent of the unprotected population on the ground are assumed to be a casualty, and outside of which 100 percent of the population are assumed not to be a casualty. An effective casualty area accounts for the characteristics of the debris piece, including its size, the path angle of its trajectory, impact explosions, and debris skip, splatter, and bounce. An effective casualty area also accounts for the size of a person.
*Energetic liquid* means a liquid, slurry, or gel, consisting of, or containing an explosive, oxidizer, fuel, or combination of the above, that may undergo, contribute to, or cause rapid exothermic decomposition, deflagration, or detonation.
*Explosive* means any chemical compound or mechanical mixture that, when subjected to heat, impact, friction, detonation or other suitable initiation, undergoes a rapid chemical change that releases large volumes of highly heated gases that exert pressure in the surrounding medium. The term applies to materials that either detonate or deflagrate.
*Explosive division* means the division within hazard class 1 of an explosive as defined in the United Nations Organization classification system for transport of dangerous goods, and as determined in accordance with 49 CFR part 173, subpart C.
*Explosive equivalent* means a measure of the blast effects from explosion of a given quantity of material expressed in terms of the weight of trinitrotoluene (TNT) that would produce the same blast effects when detonated.
*Explosive hazard facility* means a facility or location at a launch site where solid propellants, energetic liquids, or other explosives are stored or handled.
*Flight azimuth* means the initial direction in which a launch vehicle flies relative to true north expressed in degrees-decimal-degrees.
*Flight corridor* means an area on the Earth's surface estimated to contain the hazardous debris from nominal flight of a launch vehicle, and non-nominal flight of a launch vehicle assuming a perfectly functioning flight termination system or other flight safety system.
*Guided suborbital launch vehicle* means a suborbital rocket that employs an active guidance system.
*Hazard class* means the class of an explosive as defined by the United Nations Organization classification system for transport of dangerous goods, and as determined in accordance with 49 CFR part 173, subpart C.
*Impact dispersion area* means an area representing an estimated three standard deviation dispersion about a nominal impact point of an intermediate or final stage of a suborbital launch vehicle.
*Impact dispersion factor* means a constant used to estimate, using a stage apogee, a three standard deviation dispersion about a nominal impact point of an intermediate or final stage of a suborbital launch vehicle.
Impact dispersion radius (R i ) means a radius that defines an impact dispersion area.
*Impact range* means the distance between a launch point and the impact point of a suborbital launch vehicle stage.
*Impact range factor* means a constant used to estimate, when multiplied by a stage apogee, the nominal impact point of an intermediate or final stage of a suborbital launch vehicle.
*Instantaneous impact point (IIP)* means an impact point, following thrust termination of a launch vehicle. IIP may be calculated with or without atmospheric drag effects
*Intraline distance* means the minimum distance permitted between any two explosive hazard facilities in the ownership, possession or control of one launch site customer.
*Launch area* means, for a flight corridor defined in accordance with appendix A of this part, the portion of a flight corridor from the launch point to a point 100 nautical miles in the direction of the flight azimuth. For a flight corridor defined in accordance with appendix B of this part, a launch area is the portion of a flight corridor from the launch point to the enveloping line enclosing the outer boundary of the last debris dispersion circle.
*Launch point* means a point on the Earth from which the flight of a launch vehicle begins, and is defined by its geodetic latitude, longitude and height on an ellipsoidal Earth model.
*Liquid propellant* means: ( 1 ) A monopropellant on a launch vehicle or related device; or
( 2 ) Incompatible energetic liquids co-located for purposes of serving as propellants on a launch vehicle or a related device where the incompatible energetic liquids are housed in tanks connected by piping for purposes of mixing.
*Maximum credible event* means a hypothesized worst-case accidental explosion, fire, or agent release that is likely to occur from a given quantity and disposition of explosives, chemical agents, or reactive material.
*Net explosive weight (NEW)* means the total weight, expressed in pounds, of explosive material or explosive equivalency contained in an item.
*Nominal* means, in reference to launch vehicle performance, trajectory, or stage impact point, a launch vehicle flight where all launch vehicle aerodynamic parameters are as expected, all vehicle internal and external systems perform as planned, and there are no external perturbing influences (e.g., winds) other than atmospheric drag and gravity.
*Overflight dwell time* means the period of time it takes for a launch vehicle's IIP to move past a populated area. For a given populated area, the overflight dwell time is the time period measured along the nominal trajectory IIP ground trace from the time point whose normal with the trajectory intersects the most uprange part of the populated area to the time point whose normal with the trajectory intersects the most downrange part of the populated area.
*Overflight exclusion zone* means a portion of a flight corridor which must remain clear of the public during the flight of a launch vehicle.
*Populated area* means a land area with population.
*Population density* means the number of people per unit area in a populated area.
*Position data* means data referring to the current position of a launch vehicle with respect to flight time expressed through the X, Y, Z coordinate system.
*Public area* means any area outside a hazard area and is an area that is not in the possession, ownership or other control of a launch site operator or of a launch site customer who possesses, owns or otherwise controls that hazard area.
*Public area distance* means the minimum distance permitted between a public area and an explosive hazard facility.
*Public traffic route* means any highway or railroad that the general public may use.
*Public traffic route distance* means the minimum distance permitted between a public highway or railroad line and an explosive hazard facility.
*Trajectory* means the position and velocity components as a function of time of a launch vehicle relative to an x, y, z coordinate system, expressed in x, y, z, ẋ, ẏ, ż.
*Unguided sub-orbital launch vehicle* means a sub-orbital rocket that does not have a guidance system.
*X, Y, Z coordinate system* means an orthogonal, Earth-fixed, topocentric, right-handed system. The origin of the coordinate system is at a launch point. The x-axis coincides with the initial launch azimuth and is positive in the downrange direction. The y-axis is positive to the left looking downrange. The xy-plane is tangent to the ellipsoidal earth model's surface at the origin and perpendicular to the geodetic vertical. The z-axis is normal to the xy-plane and positive directed away from the earth.
φ *0* , *λ* *0*, *h* *0* means a latitude, longitude, height system where φ0 is the geodetic latitude of a launch point, λ0 is the east longitude of the launch point, and h0 is the height of the launch point above the reference ellipsoid. φ0 and λ0 are expressed in degrees-decimal-degrees.
[Doc. No. FAA-1999-5833, 65 FR 62861, Oct. 19, 2000, as amended by Amdt. 420-3, 72 FR 17019, Apr. 6, 2007; Amdt. 420-6, 77 FR 55113, Sept. 7, 2012; Doc. No. FAA-2019-0229, Amdt. 420-9, 85 FR 79716, Dec. 10, 2020]