SA-5 (Apollo)
Encyclopedia
SA-5 was the first launch of the Block II Saturn I
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...

 rocket and was part of the Apollo Program
Project Apollo
The Apollo program was the spaceflight effort carried out by the United States' National Aeronautics and Space Administration , that landed the first humans on Earth's Moon. Conceived during the Presidency of Dwight D. Eisenhower, Apollo began in earnest after President John F...

.

Upgrades and objectives

The major changes that occurred on SA-5 were that for the first time the Saturn I would fly with two stages - the S-I first stage and the S-IV
S-IV
The S-IV was the second stage of the Saturn I, a rocket-powered launch vehicle used by NASA for early flights in the Apollo program.The S-IV was manufactured by the Douglas Aircraft Company and later modified by them to the S-IVB, a similar but distinct stage used on the Saturn IB and Saturn V...

 second stage. The second stage featured six engines burning liquid hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

. Although this design was meant to be tested several years earlier in the Centaur rocket design, in the end the first Centaur launch was only two months before SA-5. This rocket stage was delivered to the Cape by a modified B-377 aircraft, nicknamed the Pregnant Guppy.

Other major design changes included the enlargement of the fuel tanks on the first stage. For the first time the rocket would carry its planned 750,000 lb
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...

 (340,000 kg) of propellant and would use eight upgraded engines producing a thrust each of 188,000 lbf
Pound-force
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...

 (836 kN). The first stage also featured for the first time eight fins for added stability during flight. But as with the earlier flight the rocket would still carry only a Jupiter-C
Jupiter-C
The Jupiter-C was an American sounding rocket used for three sub-orbital spaceflights in 1956 and 1957 to test re-entry nosecones that were later to be deployed on the more advanced PGM-19 Jupiter mobile missile....

 nosecone instead of a boilerplate Apollo spacecraft.

Also the guidance and control computer on the rocket was positioned above the second stage. This was where it would be found on the Saturn V flights that would take astronauts to the moon. The Instrument Unit controlled the ascent of the rocket through the atmosphere, automatically compensating for any winds or loss of thrust during the ascent.

For the first time in the Apollo program, this flight would be an orbital mission. This was possible because of the upgraded first stage and the addition of the second stage. It would enter into a highly ellipitical
Ellipse
In geometry, an ellipse is a plane curve that results from the intersection of a cone by a plane in a way that produces a closed curve. Circles are special cases of ellipses, obtained when the cutting plane is orthogonal to the cone's axis...

 orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...

 and re-enter a couple of days later as its orbit decayed.

U.S. President John F. Kennedy
John F. Kennedy
John Fitzgerald "Jack" Kennedy , often referred to by his initials JFK, was the 35th President of the United States, serving from 1961 until his assassination in 1963....

 referred specifically to this launch in a speech he gave at Brooks AFB in San Antonio, Texas, on November 21, 1963, the day before he was assassinated. He said:
And in December, while I do not regard our mastery of space as anywhere near complete, while I recognize that there are still areas where we are behind -at least in one area, the size of the booster- this year I hope the United States will be ahead.

Flight

The first scheduled launch attempt was for 27 January 1964, with all going well until 93% of the liquid oxygen
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...

 (LOX) had been loaded into the first stage. At this time, the ground crews switched it from a fast fill to a replenish system. However, the LOX in the tanks began to fall, i.e., it was not being replenished. The cause was found to be a flange (a plate without an opening) in the line. This could not be removed easily and the launch had to be postponed for two days.

The second launch attempt had no such problems and lifted off into overcast skies at January 29, 1964, 11:25 EST
Eastern Time Zone
The Eastern Time Zone of the United States and Canada is a time zone that falls mostly along the east coast of North America. Its UTC time offset is −5 hrs during standard time and −4 hrs during daylight saving time...

. The rocket
Rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

 sent back 1,183 measurements to the ground during the flight while at the same time it was tracked by six telescopes. For the first 1000 meters the rocket was filmed by 13 cameras that looked for any pitch, yaw, and roll
Flight dynamics
Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw .Aerospace engineers develop control systems for...

 movements.

The separation of the two rocket stages was filmed by eight cameras that themselves separated from the rocket to be recovered 800 km downrange in the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

. The whole stage separation system worked perfectly with the retrorockets firing on the first stage to decelerate it and ullage rockets on the S-IV firing to settle its fuel to aft of the stage.

After an eight minute burn, the second stage entered into a 262 km by 785 km orbit. At 16,965 kg it was the largest satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....

 ever to go into orbit at that time. However, the achievement of Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

 orbit was not an objective of the mission but merely a bonus. It did show to the American public that the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 had bridged the missile gap
Missile gap
The missile gap was the term used in the United States for the perceived disparity between the number and power of the weapons in the U.S.S.R. and U.S. ballistic missile arsenals during the Cold War. The gap only existed in exaggerated estimates made by the Gaither Committee in 1957 and United...

.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK