Viking (rocket)

Launch of Viking 4

On 3 May 1949, after two static firings (11 March and 25 April), the first Viking rocket took off from White Sands Missile Range in New Mexico. Its engine fired for 55 seconds, ten seconds short of the hoped-for maximum of 65, but the rocket flew on course and reached an altitude of 51 mi (82 km)—deemed a good start to the program.[1]^: 84–93 Viking 2, launched four months later, also suffered from premature engine cutoff and only made it to 33 mi (53 km). Both had suffered from leaks in their turbines, the intense heat of the steam breaking the seal of the turbine casing. The solution was to weld the casing shut, there being no reason to access the turbine wheel again after a flight.[1]^: 98–102

The fix worked, and Viking 3, launched 9 February 1950 and incorporating an integrated (rather than discrete) oxygen tank, reached 50 mi (80 km) and could have gone higher. However, after 34 seconds of accurately guided flight, the rocket veered westward and threatened to leave the launch range. Range safety triggered charges in the rocket to separate the nose from the engine, and both tumbled to the ground, where they were recovered for analysis.[1]^{: 108–114}

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.[1]^{: 108–114} Viking 4 was identical to Viking 3, the first of the series not incorporate design changes to fix a problem on a previous Viking.}[5]^: 255 On 10 May 1950, from a site in the Pacific Ocean between Jarvis Island and Kiritimati, the fourth Viking became the first sounding rocket ever launched from a sea-going vessel. The flight was perfect, reaching 106.4 mi (171.2 km), more than double that reached by Vikings 1 and 3.[1]^{: 108–114}

Viking 5, launched 21 November 1950 carried a vast array of photomultiplier tubes, ionization chambers and Geiger counters, for the detection of 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 108 miles (174 km) as well as Pirani gauges to measure air densities in the upper atmosphere.[1]^{: 148, 236} 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 40 miles (64 km).[1]^{: 151–153, 236}

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 136 miles (219 km).[1]^{: 167–171, 236}

Viking 9 takes off 15 December 1952

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, allowing the rocket 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 in the hope that it would clear the immediate area and thus pose no danger to ground crew, Nat Wagner, head of the "Cutoff group" delivered a command to the rocket to cease its thrust. 65 seconds later, the rocket crashed 4 miles (6.4 km) or 5 miles (8.0 km) downrange to the southeast.[1]^{: 172–181}

With lessons learned from the Viking 8 failure, the successful 9 December static firing of Viking 9 was followed on 15 December by a successful launch from White Sands. The rocket reached an altitude of 135 miles (217 km), roughly the same as that of the first-generation Viking 7, launched in 1950. In addition to cameras that photographed the Earth during flight, Viking 9 carried a full suite of cosmic ray, ultraviolet, and X-ray detectors, including sixteen plates of emulsion gel for tracking the path of individual high energy particles. The experiment package was recovered intact after it had secured measurements high in the Earth's upper atmosphere.[1]^{: 185–203}

On 25 May 1953, Viking 10, originally planned to be the last of the Vikings, arrived at White Sands Missile Range in New Mexico. A successful static firing on 18 June cleared the way for a 30 June launch date, a schedule that had been made months prior, before the rocket had even left the Glenn L. Martin Company plant where it had been built. At the moment of liftoff, the tail of Viking 10 exploded, setting the rocket afire. Water was immediately flooded into the rocket's base in an attempt to extinguish the fire, but flames continued to burn in the East Quadrant of the firing platform. Half an hour after launch, two of the launch team under manager Milton Rosen were dispatched to put out the fire to salvage what remained of the rocket.

Their efforts were successful but then were threatened by a slow leak in the propellant tank. The vacuum created by the departing fuel was causing the tank to dimple with the danger of implosion that would cause the rocket to collapse. Lieutenant Joseph Pitts, a member of the launch team, shot a rifle round into the tank, equalizing the pressure and saving the rocket. Three hours after the attempted launch, the last of the alcohol propellant had been drained from Viking 10. The launch team was able to salvage the instrument package of cameras, including X-ray detectors, cosmic ray emulsions, and a radio-frequency mass-spectrometer, valued at tens of thousands of dollars, although there was concern that the rocket was irreparable.

A thorough investigation of the explosion began in July, but a conclusive cause could not be determined. In a report presented in September, Milton Rosen noted that a similar occurrence had not happened in more than 100 prior tests of the Viking motor. It was decided to rebuild Viking 10, and a program for closer monitoring of potential fail points was implemented for the next launch, scheduled for 1954.[1]^{: 204–221} Ten months of salvage, testing, and troubleshooting followed the failed launch.

On 30 June 1953, the rebuilt rocket was once again ready for launch. A successful static firing took place at the end of April 1954, and launch was scheduled for 4 May. Control issues revealed in the static firing as well as gusty, sand-laden winds caused a delay of three days. At 10:00 AM local time, Viking 10 blasted off from its pad at the White Sands Missile Range in New Mexico, reaching an altitude of 136 mi (219 km)—a tie with the highest altitude ever reached by a first-generation Viking (Viking 7 on 7 August 1951). Data was received from the rocket for all stages of the flight, and its scientific package, including an emulsion experiment, returned the first measurement of positive ion composition at high altitudes.[1]^{: 221–236}

Viking 12 infrared photo of the Earth taken 4 February 1955

Viking 11, which was ready for erection on 5 May, also had a successful static test and was ready for launch, 24 May 1954. Again, the countdown went without hold, and Viking 11, the heaviest rocket yet in the series, was launched at 10:00 AM. Forty seconds into the flight, several puffs of smoke issued from the vehicle, but these accidental excitations of the rocket's roll jets did no harm. Viking 11 ultimately reached 158 mi (254 km) in altitude, a record for the series, taking the highest altitude photographs of the Earth to date. Viking 11 carried a successful emulsions experiment, measuring cosmic rays at high altitudes.[1]^{: 221–236}

The final Viking flight was that of Viking 12, launched 4 February 1955. Reaching an altitude of 143.5 mi (230.9 km), the rocket's K-25 camera took an infrared picture of the Southwestern United States, from the Pacific coast to Phoenix, just after reaching its apogee.[6]