Improved Syncom C Set for May Launch—Hughes News April 10, 1964

Syncom C, an improved version of Syncom 2 that has performed so spectactularly since last July 26, will be shipped from the El Segudno plant next week to the John F. Kennedy Space Center in preparation for launching into a synchronous orbit early in May.

Syncom C has been undergoing extensive tests for several weeks and at presstime all systems aboard the tine spacecraft were “go.”

Leaning heavily on experience gained from the success of the Syncom 2 spacecraft, personnel in Space Systems Division have incorporated several improvements into Syncom C, which will become Syncom 3 the moment it lifts off the pad at Cape Kennedy in May.

Probably the most significant improvement will be in the solar cells which help provide power for the spacecraft’s systems. On Syncom 2 the soar cells were the P on N type with a 6 mill glass cover, providing minimal protection against radiation.

In Syncom C, N on P type solar cells with a 12-mil fused silica quartz cover will be used, providing 10 times the resistance to radiation.

“This will assure in excess of three years of oribital operation before any restriction will be placed on full 24-hour day use of the satellite’s communication systems,” said R. M. “Dick Bentley, Syncom manager, Communications Satellite Laboratory.

The major threat to the solar cells , Mr. Bentley said is the Van Allen radiation belt, which extends on past the 22,300 mile orbit on the synchronous Syncoms. Solar cells on Syncom 2, for example have shown 24 per cent degradation from radiation. It now appears that it will continue to operate effectively until March 1965, though becoming somewhat marginal after September 1964.

A second major improvement involving solar cells in the new fabrication technique which provides a better solar panel structurally from the adhesive standpoint. Preston DuPont of Space Systems developed the technique, which with the support of Components and Materials Lab, which saved 1 pound of weight on the spacecraft, a significant reduction.

With Mr. DuPont’s technique all solar cells are applied to the panel simultaneously through a vacuum differential method, with only a thin layer of epoxy provided the adhesive. The technique has proved extremely successful in ground tests in the Space Environmental Laboratory, with no structural defects or loss of cells due to failure in the bonding.

Syncom is the first spacecraft in history to make use of a hydrogen peroxide control system for a period longer than two weeks.  Syncom 2 uses a combination of hydrogen and nitrogen systems and both have operated effectively, but the dual hydrogen peroxide in the Syncom C system will give increased satellite control capability.

Hydrogen peroxide, with a higher specific impulse, gives more energy per pound of fuel, resulting in 600 feet per second of control capability in the continual pulse mode of Syncom C. The nitrogen-hydrogen combination systems on Syncom 2 gave 350 feet per second capability.

“We’re completely confident, from our experience with the hydrogen peroxide system on Syncom 2, which has performed all types of space maneuvering, that we have a perfectly clean system not subject to corrosion associated with hydrogen peroxide and its containers,” Mr. Bentley said. “Though even a speck of contamination can adversely effect a hydrogen peroxide system, we feel that our procedures are adequate so that no corrosion will exist.”

The other major improvement to Syncom C involves changing one of the transponders from two 500 kc channels for two-way voice communication to dual mode capability.  By command from the ground, the transponder bandwidth can be switched from 10 megacycles for transmitting television to 50 kc for optimum relaying of messages from small terminals.

Syncom C, built in 1962, served as the backup spacecraft for the earlier Syncom launches and has been under the direction of Spacecraft Engineer Bill Penprase from the start of assembly.

“Bill has virtually lived with this spacecraft for two years being totally in charge,” Mr. Bentley said. “He deserves a great deal of credit for getting Syncom C rebuilt, including a new wiring harness, and supervising all the subsequent tests to keep us right on the launch schedule established by NASA.”

Mr. Penprase will continue his vigil over Syncom C right up until it is launched, being one of the last men on the pad before it is boosted into its orbit.

One thought on “Improved Syncom C Set for May Launch—Hughes News April 10, 1964

  1. Hi jack

    I remember getting the airlines ready for the launch. We picked up the telemetry signal on launch from the bendix location( twa). That morning I was having breakfast with Harold Rosen at the Madison hotel in Washngthion when (Boris Subbotin ?) came in and said “we cant inject because all the orientation signals appear to be backwards!! Harold said how do they read when read backwards. Boris cane back in a little while and said they read ok– Harold said “Then read then backwards and inject”

    – everything went fine and Syncom 3 was injected into a stationary orbit.

    Roland