AS-104 was the fourth orbital test of a
boilerplate Apollo spacecraft
The Apollo spacecraft was composed of three parts designed to accomplish the American Apollo program's goal of landing astronauts on the Moon by the end of the 1960s and returning them safely to Earth. The expendable (single-use) spacecraft ...
, and the second flight of the
Pegasus micrometeoroid detection satellite. It was launched by SA-8, the ninth
Saturn I
The Saturn I was a rocket designed as the United States' first medium lift launch vehicle for up to low Earth orbit payloads.Terminology has changed since the 1960s; back then, 20,000 pounds was considered "heavy lift". The rocket's first sta ...
carrier rocket.
Objectives
The primary mission objective was to demonstrate the launch vehicle's iterative guidance mode and to evaluate system accuracy. The launch trajectory was similar to that of mission AS-103.
The Saturn launch vehicle SA-8 and payload were similar to those of mission AS-103, except that a single reaction control engine assembly was mounted on the boilerplate
service module
A service module (also known as an equipment module or instrument compartment) is a component of a crewed space capsule containing a variety of support systems used for spacecraft operations. Usually located in the uninhabited area of the spacec ...
(BP-26). The assembly was instrumented to acquire additional data on launch environment temperatures. This assembly also differed from the one on the AS-101 mission in that two of the four engines were of a prototype configuration instead of all engines being simulated.
Launch
This was the first nighttime launch in the Saturn I series. A built-in 35 minute hold was used to ensure that launch time coincided with the opening of the launch window.
AS-104 was launched from Cape Kennedy Launch Complex 37B at 2:35:01 a.m. EST (07:35:01 GMT) on May 25, 1965. The launch was normal and the payload was inserted into orbit approximately 10.6 minutes after lift-off. The total mass placed in orbit, including the spacecraft, Pegasus B, adapter, instrument unit, and
S-IV
The S-IV was the second stage of the Saturn I rocket 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 t ...
stage, was 34,113 pounds (15,473 kg). The perigee and apogee were 314.0 and 464.1 miles (505 and 747 km), respectively; the orbital inclination was 31.78'. The 1397 kilogram (3080-pound)
Pegasus 2
Pegasus 2 or Pegasus II, known before launch as Pegasus B was an American satellite which was launched in 1965 to study micrometeoroid impacts in Low Earth orbit. It was the second of three Pegasus satellites to be launched, following the launc ...
satellite was also carried to orbit by SA-8, being stowed inside the boilerplate's service module, and remaining attached to the S-IV stage.
The actual trajectory was close to the one predicted, and the spacecraft was separated 806 seconds after lift-off. Several minor malfunctions occurred in the S-I stage propulsion system; however, all mission objectives were achieved.
References
External links
NSSDC: SA-8Manned space flight network performance analysis for the SA-8 mission
{{Use American English, date=January 2014
Apollo program
Spacecraft launched in 1965
1965 in the United States
Test spaceflights
Spacecraft launched by Saturn rockets