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. 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 —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. Final flights 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 in altitude, a record for the series, snapping the highest altitude photographs of the Earth to date. Viking 11 carried a successful emulsions experiment, measuring cosmic rays at high altitudes. The final Viking flight was that of Viking 12, launched 4 February 1955. Reaching an altitude of , the rocket's K-25 camera snapped an infrared picture of the Southwestern United States, from the Pacific coast to Phoenix, just after reaching its apogee. Viking into Vanguard The Viking series returned a bonanza of scientific information measuring temperature, pressure, density, composition and winds in the upper atmosphere and electron density in the ionosphere, and recording the ultraviolet spectra of the Sun, The success