the engine, and both tumbled to the ground, where they were recovered for analysis. With successful tests of the engine and guidance systems conducted (though not on the same missions), Viking was deemed ready for its most ambitious test: shipboard launch from the deck of the USS Norton Sound. Viking 4 was identical to Viking 3, the first of the series not incorporate design changes to fix a problem on a previous Viking.} On 10 May 1950, from a site in the Pacific Ocean between Jarvis Island and Christmas Island, the fourth Viking became the first sounding rocket ever launched from a sea-going vessel. The flight was perfect, reaching , more than double that reached by Vikings 1 and 3. Viking 5, launched 21 November 1950 carried a vast array of photomultiplier tubes, ionization chambers and Geiger counters, for the detection radiation across a wide variety of energies and types. The rocket also carried two movie cameras to take high altitude film of the Earth all the way to its peak height of as well as Pirani gauges to measure air densities in the upper atmosphere. Viking 6, launched 11 December, carried a much lighter payload, but its experiments included a battery of custom built pressure gauges. The rocket underperformed, however, only reaching a maximum altitude of . The first generation of Vikings reached its acme of performance with the flight of Viking 7, the sole Viking launch of 1951. Launched 7 August from White Sands, the rocket set a new world altitude record of . Second model (Vikings 8-12) In the late spring of 1952, the Naval Research Laboratory team under the management of Milton Rosen prepared to launch the first second-generation Viking, Viking 8, from White Sands Missile Range in New Mexico. The new Viking design was nearly half-again as wide as its precursor, affording the highest fuel-to-weight ratio of any rocket yet developed. The tail fins no longer supported the weight of the rocket, has had previously been the case. Now, the Viking rocket rested on the base of its fuselage. This allowed the tail fins to be made much lighter, one of many ways the Viking was redesigned to carry a heavier tank without weighing more than the first Viking design. On 6 June 1952, Viking 8 broke loose of its moorings during a static firing test. After it was allowed to fly for 55 seconds