A-104 (spacecraft)

The mission A-104 (also called Pegasus 2) was the second of three flights as part of the Apollo program, NASA, took an active research satellite into space. A two-stage Saturn I with a dummy of the Apollo spacecraft transported the satellite Pegasus 2 into a low Earth orbit (LEO ). The mission differed only slightly from A- 103.


The object of the Pegasus missions was to investigate the incidence of micrometeorites on the order of 1.E - 7 to 1.E -4 g in the near-Earth space. Demonstration of the iterative control mode offers the rocket. Evaluation of the functions of Apollo and Saturn, as well as the Apollo rocket apparatus (LES ).


Active Launch Escape System ( LES): Functional rescue rocket with 4.70 m height. Escape tower, a 3.05 m high support structure for the rescue rocket.

Apollo dummy (BP -26), the lifelike model (English Boilerplate called ) weighed 4400 kg and consisted of the Command Module (CM ): a conical aluminum construction with a base diameter of 3.91 m and 3.56 m in height and the service module (SM): an aluminum construction served as a payload fairing of the satellite was mounted on the instrument unit of the second stage by means of an adapter section. One of the simulated control jets ( RCS) was fitted to the temperatures during the start record. One difference from A-101 was that there were now two out of four of these control thrusters prototypes and not all just dummies.

The Pegasus satellite was firmly attached to the second stage, measure 5.28 x 2.13 x 2.41 meters and weighed 1805 kg. The central unit comprised the electronics, sensors, solar panels and the mechanics of deploying the two retractable detector surfaces. These were 29.3 meters long, 4.3 meters wide and registered the micro- meteorite impact.


The steps were delivered 25 February to 8 March 1965 Kennedy Space Center and built on the Launch Complex 37B. There were no significant complications.

History of the flight

The launch took place on 25 May in 1965 7:41:00 UTC, he was ( 02:41 local time ) the first night launch of a Saturn I. After the first stage was separated and had the second ignited, and the LES through which was engines of rescue rocket separated as planned.

10 minutes and 42 seconds after the start waving the rocket into orbit. Approximately two and a half minutes later, the Apollo spacecraft from the second stage was ( and to their mounted satellite ) isolated and placed on a separate trajectory. Pegasus remained in the planned orbit and unfolded a minute later his detector surfaces.

His life had been planned for about 1220 days. The satellite instruments and the radio signals were switched off on August 29, 1968. On November 3, 1979, the satellite burned up in the atmosphere.

Impact on the Apollo program

The mission was a complete success. While were minor malfunctions at the first stage, there were but achieved all goals.

The next mission was to bring the third and final Pegasus satellites into space.


NASA joined in 1964 the first stage manufacturer. Model Serial No. SA -9 is the last of eight, which was manufactured by Marshall; SA -8, SA -10 and the following for the Saturn IB should come from Chrysler. Since Chrysler for the development took some time longer flew SA -9 first. The mission designations ( A-101 to A -105 ), however, remained chronologically. So A-103/SA-9 and A-104/SA-8 revealed.