was the first Saturn I
The Saturn I was the United States' first heavy-lift dedicated space launcher, a rocket designed specifically to launch large payloads into low Earth orbit. Most of the rocket's power came from a clustered lower stage consisting of tanks taken from older rocket designs and strapped together to make...
space launch vehicle, the first in the Saturn family, and was part of the American Apollo program. The rocket was launched on October 27, 1961 from Cape Canaveral
Cape Canaveral Air Force Station is an installation of the United States Air Force Space Command's 45th Space Wing, headquartered at nearby Patrick Air Force Base. Located on Cape Canaveral in the state of Florida, CCAFS is the primary launch head of America's Eastern Range with four launch pads...
The Saturn I booster was a huge increase in size and power over anything previously launched. It was three times taller, required six times more fuel and produced ten times more thrust than the Jupiter-C rocket that had launched the first American satellite, Explorer 1
, into orbit in 1958.
At the time, NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
had decided to not use all-up testing, when an entire system is tested at once. The agency planned to test each rocket stage in separate launches, so for SA-1 the only live stage was the S-I first stage.
This first flight was designed to test the structure of the launch vehicle during a suborbital flight using the nose cone from a Jupiter rocket.
As this was the first Saturn flight, the systems were still being developed. It was the first time that a stage had been delivered to Cape Canaveral by barge and it demonstrated this could be done for the larger stages of future Saturn rockets.
The first stage and the two dummy upper stages arrived on August 15, 1961 on the barge Compromise
. It had encountered some problems on the voyage, running aground four times due to poor nautical chart
A nautical chart is a graphic representation of a maritime area and adjacent coastal regions. Depending on the scale of the chart, it may show depths of water and heights of land , natural features of the seabed, details of the coastline, navigational hazards, locations of natural and man-made aids...
s. On the return trip, the barge hit a bridge, causing some minor damage.
The booster was erected at Pad 34
Cape Canaveral Air Force Station Launch Complex 34 is a launch site on Cape Canaveral, Florida. LC-34 and its twin to the north, LC-37, were used by NASA as part of the Apollo Program to launch Saturn I and IB rockets from 1961 through 1968...
five days later with little trouble. Testing proceeded, albeit a little behind schedule. At this time, testing was not automated and amounted to flicking switches in the control center and observing how the rocket responded.
At 12:30 p.m. EST on October 26, 1961, the RP-1
RP-1 is a highly refined form of kerosene outwardly similar to jet fuel, used as a rocket fuel. Although having a lower specific impulse than liquid hydrogen , RP-1 is cheaper, can be stored at room temperature, is far less of an explosive hazard and is far denser...
propellant started to flow into the rocket. One hundred and three percent of the fuel required was put into the rocket, as it was possible to easily drain fuel. Just before launch, surplus fuel was removed from the tanks.
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
began flowing into its tanks at 3:00 a.m. the next day. It followed the same procedure as the RP-1 with the tanks being filled to 10 percent to check for leaks, then fast filled to 97 percent, then slowly topped off.
Despite a couple of delays due to bad weather, the rocket was launched only one hour behind schedule. The engineers had given the rocket only a 75 percent chance of lifting off and only a 30 percent chance of completing a nominal flight. Even with a nominal flight some damage was thought possible. At the Redstone Arsenal
Redstone Arsenal is a United States Army base and a census-designated place adjacent to Huntsville in Madison County, Alabama, United States and is part of the Huntsville-Decatur Combined Statistical Area...
, ground testing had shattered windows 12 km away.
The sound of the launch was a disappointment for some witnesses, being described as like an Atlas rocket launch, when observers stood 1.5 miles (2.4 km) away instead of three miles (5 km) for a Saturn launch. It was later determined that the cause of the difference between the Cape and the Redstone Arsenal was atmospheric conditions damping the sound.
The flight itself was nearly perfect. The rocket reached a height of 136.5 km and impacted 345.7 km down range from the launch site in the Atlantic Ocean. The only real problem was the rocket cut off 1.6 seconds ahead of schedule. This was traced to the fact that there was 400 kg too much liquid oxygen and 410 kg too little RP-1. For the test flight, SA-1 only carried a propellant load that was 83 percent full.