Uprated Saturn I (Saturn IB)

The space agency, using the building-block approach, conceived the Uprated Saturn I as the quickest, most reliable, and most economical means of provid­ing a vehicle with greater payload than the Saturn

I. This vehicle was planned for orbital missions with the Apollo spacecraft before the Satum V vehicle would be available.

The Uprated Satum I is based on a blending of existing elements of Saturn I and Saturn V. A re­designed Saturn I booster (designated the S-IB stage), and an S-IVB upper stage and instrument unit from the Satum V are used on this launch vehicle.

Maximum use of designs and facilities available from the earlier approved Satum programs saved both time and costs. .

The Satum I first stage was redesigned in several areas by NASA and the Chrysler Corporation, the stage contractor, for the expanded role as the Up­rated Saturn I booster. Basically, it retained the same shape and size, but required some modifica­tion for mating with the upper stage, which has a greater diameter and weight than the Satum I upper stage.

Stage weight was cut by more than 20,000 pounds to increase payload capacity. The Rocketdyne H-l engine was uprated to 200,000 pounds of thrust, compared with 188,000 pounds of thrust for each engine in the final Saturn I configuration. The en­gines will be improved again to 205,000 pounds beginning with the SA-206.

For the Uprated Saturn I, a guidance computer used in the early Satum I was replaced by another IBM computer of completely new design which in­corporates the added flexibility and extreme re­liability necessary to carry out the intended Uprated Satum I missions.

The Uprated Satum I, topped by the Apollo spaee-

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craft, stands approximately 224 feet tall, and is about 21.7 feet in diameter. Total empty weight is about 85 tons, and liftoff weight fully fueled is approximately 650 tons.

Several uprated Saturn I vehicles have been launched since the original SA 201 launch on Feb. 26, 1966.