S-I

{{Infobox rocket stage

|name=S-I

|status=Retired

|country-origin=United States

|last=July 30, 1965

|first=October 27, 1961

|family=Saturn

|image=S-I rocket stage.jpg

|success=10|launches=10

|rockets=Saturn I

|diameter=6.5 m (21.4 feet)

|length=

|height=24.5 m (80.3 feet)

|country=United States

|caption=S-I diagram

|manufacturer=Chrysler

|propmass=397,414 kg (854,101 lb)

|mass=432,681 kg (953,898 lb)

|empty=45,267 kg (99,796 lb)

|stagedata=

{{Infobox rocket/stage

|name=S-I engine details

|fuel=RP-1 / LOX

|time=150 s

|thrust=(vac) 7,582.1 KN (1,704,524 lbf)

|engines=8 H-1 engines

|SI=289 sec

}}

The S-I was the first stage of the Saturn I rocket used by NASA for the Apollo program.{{Cite web|last=|first=|date=|title=S-I stage|url=http://www.astronautix.com/s/s-istage.html|url-status=live|archive-url=https://web.archive.org/web/20161228040121/http://astronautix.com/s/s-istage.html|archive-date=December 28, 2016|access-date=|website=}}

Design

The S-I stage was powered by eight H-1 rocket engines{{Cite web|last=|first=|date=|title=Saturn family|url=https://space.skyrocket.de/doc_lau_fam/saturn.htm|access-date=|website=}} burning RP-1 fuel with liquid oxygen (LOX) as oxidizer. The design of the S-I was based on Jupiter and Redstone tanks to leverage existing chains. A central Jupiter tank{{Cite web|last=|first=|date=|title=Saturn Illustrated Chronology – Part 1|url=https://history.nasa.gov/MHR-5/part-1.htm|access-date=|website=}} was surrounded by a cluster of eight Redstone tanks. Four of these Redstone tanks contained LOX and four contained RP-1. The outer tanks were painted to alter thermal conditions inside the tanks and to provide a "roll pattern" used to estimate radial motion during flight.{{Cite web|last=|first=|date=|title=Saturn Illustrated Chronology - Part 2|url=https://history.nasa.gov/MHR-5/part-2.htm|access-date=|website=}} The engines were arranged in two clusters, a group of four fixed central engines and a group of four outer gimbaled engines. The gimbals allowed the stage to be controlled with thrust vectoring. On launches after SA-5, eight fins were added to enhance control during atmospheric flight.

History

The S-I stage was developed by Chrysler and consisted of 9 tanks that were previously used on existing rockets. The central tank was a Jupiter tank that held liquid oxygen. This Jupiter tank was sounded by eight Redstone tanks, four for liquid oxygen and four for RP-1. The first four launches had no fins on the S-I, but the remaining six added them to improve stability during atmospheric flight.{{Cite web|last=|first=|date=|title=Saturn I & IB Rockets|url=https://historicspacecraft.com/Rockets_Saturn.html|access-date=|website=}} The initial launch of the Saturn I consisted of an active S-I, an inactive S-IV and inactive S-V stage. Tensions were high as a launch vehicle of this size had never flown before. The S-I was partially loaded with propellant to lessen the destruction if an anomaly occurred near or on the pad.{{Cite web|last=|first=|date=|title=Saturn I|url=http://www.astronautix.com/s/saturni.html|url-status=live|archive-url=https://web.archive.org/web/20160820171246/http://www.astronautix.com/s/saturni.html|archive-date=August 20, 2016|access-date=|website=}} In the end, the launch was successful and the subsequent SA-5 launch was identified by John F. Kennedy as the launch that put the U.S. above the USSR in terms of lift capability.{{Cite web|last=|first=|date=|title=President John F. Kennedy's Remarks at Brooks Air Force Base, San Antonio, TX – November 21, 1963|url=https://www.youtube.com/watch?v=6DTX9OiKi9U&t=6m4s|access-date=|website=}}

Flight history

class="wikitable"

!Mission serial number

!Launch date

(UTC)

!Launch notes

SA-1

|October 27, 1961