Additional Details Disclosed
First launching of the National Aeronautics and Space Administration-Hughes synchronous communications satellite will be possible late in 1962 because of the simplicity of its design and its light weight, Project Manager C. Gordon Murphy, associate manger of the Space Systems Division, said in disclosing details of the spacecraft.
Under Project Syncom, Hughes will build three experimental high altitude communications satellites for NASA, Mr. Murphy said.
Hughes scientists have designed a small satellite which is stabilized by spinning, like a gyroscope, and which transmits a signal beam in the shape of a pancake with the “edge” toward the earth.
“This design did away with the need for complex controls and large size,” Mr. Murphy said. “Syncom will be only 28 inches in diameter, weigh 55 pounds and can be boosted to a 22,300-mile orbit by the Delta rocket of proved reliability. Yet, the satellite will be fully capable of relaying telephone conversations to Europe across thousands of miles of space.”
First of Its Type
Syncom will be the first spacecraft to be placed in a synchronous orbit, one in which a satellite’s orbital velocity is matched by the earth’s rotation so that it appears to hover over a given area, according to the project manager.
Maneuvering Syncom into a synchronous orbit and the correct longitude probably will require several days, according to Mr. Murphy. He listed the following sequence of events:
After burnout of the second stage of the Delta, the satellite will be spun up to approximately 1- ½ revolutions per second. After burnout of the third stage, Syncom will be at 160 miles altitude and at the perigee of an elliptical orbit. About 5-1/2 hours later the satellite will have “coasted” to the 22,300-mile apogee of tis orbit and will be over the Indian Ocean.
An apogee rocket motor attached to the satellite will then be fired to place it in to circular and nearly synchronous orbit. It will then drift westward to a longitude near the eastern United States. A number of small vernier rockets will then be fired to bring it to approximate synchronism with the earth’s rotation. Final precise adjustments in velocity and in the spacecraft’s attitude in space will be made by pulsing small nitrogen gas jets.
Mr. Murphy said communication experiments with the satellites will be performed by the U.S. Army’s Advent Management Agency, using Project Advent facilities, in cooperation with NASA.
The design objective of Syncom is to have an operational lifetime of one year. The project is managed by NASA’s Goddard Space Flight Center, Greenbelt, Md.
A model of Syncom was on display in the Hughes exhibit at the American Rocket Society Space Flight Report to the Nation in New York Oct 9-15.