Trailblazer was an American series of

rocket A rocket (from , and so named for its shape) is a vehicle that uses jet propulsion to accelerate without using any surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely ...

s used between 1959 and 1973 for research on

atmospheric reentry Atmospheric entry (sometimes listed as Vimpact or Ventry) is the movement of an object from outer space into and through the gases of an atmosphere of a planet, dwarf planet, or natural satellite. Atmospheric entry may be ''uncontrolled entry ...

. Both vehicles were tested at the

Wallops Flight Facility Wallops Flight Facility (WFF) is a rocket launch site on Wallops Island on the Eastern Shore of Virginia, United States, just east of the Delmarva Peninsula and approximately north-northeast of Norfolk, VA, Norfolk. The facility is operated ...

Wallops Island Wallops Island is a island in Accomack County, Virginia, part of the Virginia Barrier Islands that stretch along the eastern seaboard of the United States. It is just south of Chincoteague Island, a popular tourist destination. Wallops Isla ...

, Accomack County,

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

and were located under the

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

Langley program (itself located at the

Langley Research Center The Langley Research Center (LaRC or NASA Langley), located in Hampton, Virginia, near the Chesapeake Bay front of Langley Air Force Base, is the oldest of NASA's field centers. LaRC has focused primarily on aeronautical research but has also ...

near

Hampton Hampton may refer to: Places Australia *Hampton bioregion, an IBRA biogeographic region in Western Australia * Hampton, New South Wales *Hampton, Queensland, a town in the Toowoomba Region * Hampton, Victoria ** Hampton railway station, Melbour ...

, Virginia).

Trailblazer 1

Trailblazer 1 (

thrust Thrust is a reaction force described quantitatively by Newton's third law. When a system expels or accelerates mass in one direction, the accelerated mass will cause a force of equal magnitude but opposite direction to be applied to that ...

: 365 kN/82,055 lbf; mass: 3,400 kg/7,400 lb; height: 17.1 m/56.1 ft; diameter: 0.58 m/1.9 ft) was first launched on March 3, 1959, and was retired in 1963 (last launch: February 16, 1963). The vehicle had six stages: TX-77, M-6, M5E1, Cygnus 5, T-40, and T-55. Its first three stages took the upper stage package (Cygnus 5, T-40, and T-55 motors) to an apogee, either 260 km/162 mi or 280 km/170 mi, when the upper stages fired in unison, pushing the

payload Payload is the object or the entity that is being carried by an aircraft or launch vehicle. Sometimes payload also refers to the carrying capacity of an aircraft or launch vehicle, usually measured in terms of weight. Depending on the nature of t ...

(a 13 cm sphere) back into Earth's atmosphere at sizable reentry speeds. In each test, a different material was used, and ground workers could observe the

spectral density In signal processing, the power spectrum S_(f) of a continuous time signal x(t) describes the distribution of power into frequency components f composing that signal. According to Fourier analysis, any physical signal can be decomposed into ...

and

luminance Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls wit ...

of the artificial "

meteorite A meteorite is a rock (geology), rock that originated in outer space and has fallen to the surface of a planet or Natural satellite, moon. When the original object enters the atmosphere, various factors such as friction, pressure, and chemical ...

s" that had been created. On the 1G mission, a more realistic artificial meteorite (a 5.8 g steel bearing) was used as the payload, which was launched into the atmosphere with a reentry speed of 6 km/s by a "seventh stage", used after the sixth stage had been depleted. Thus, a reference was provided for the luminance of the trails of the artificial meteorites resulting from later tests.

Trailblazer 2

Trailblazer 2 (thrust: 547 kN/122,970 lbf; mass: 6,100 kg/13,400 lb; height: 15.7 m/51.5 ft; diameter: 0.79 m/2.59 ft) was first launched on December 14, 1961, and was retired in 1973 (last launch: December 6, 1973). Trailblazer 2 sent objects back into the atmosphere much in the same way Trailblazer 1 did, however it was much larger and stronger than Trailblazer 1. Also, due to the sheer size of it, Trailblazer 2 could hold

instruments Instrument may refer to: Science and technology * Flight instruments, the devices used to measure the speed, altitude, and pertinent flight angles of various kinds of aircraft * Laboratory equipment, the measuring tools used in a scientific lab ...

for measuring and sending

data Data ( , ) are a collection of discrete or continuous values that convey information, describing the quantity, quality, fact, statistics, other basic units of meaning, or simply sequences of symbols that may be further interpreted for ...

to the ground, greatly enhancing its utility to researchers. Trailblazer 2's apogee was around 300 km/180 mi, and its payload was around 18 kg. Its stages were Altair 1, Cygnus 15, TX-77, 1.5KS35000, and Castor 1. Like Trailblazer 1, Trailblazer 2 carried out artificial meteorite experiments. It used 0.7-0.8 g steel balls that were launched at 6.1 km/s.

References

Description and Performance of Three Trailblazer II

Trailblazer 2 Rocket Tests on the Reentry Plasma Sheath

Jonathan C. McDowell Sounding rockets of the United States {{rocket-stub