SRC-582

Satellite Power Systems (SPS) [Concept] Definition Study (Exhibit D), Volume VII - System/Subsystems Requirements Databook -- NASA CR-3399; Contract NAS8-32475; March 1981

Commissioned by Marshall Space Flight Center, Contract NAS8-32475, Exhibit D. Who paid for a study is recorded because it bears on how its conclusions should be read, not because it makes them wrong.

Published claims resting on this source

• CLM-0995 The whole ten-kilometre satellite was designed to sway once every fourteen minutes, and the antenna was required to be at least as stiff as once every ten minutes so that ordinary control could keep it pointed to a twentieth of a degree.
• CLM-0996 The beams the reference satellite would be built from are specified down to the wall thickness, and two contractors give the stiffness numbers.
• CLM-0997 The designers said how flat the antenna had to stay: within about half a metre overall, with the surface elements out of true by no more than a twelfth of a degree, under sunlight, gravity and a 24 degree temperature difference across the frame.
• CLM-0999 Rockwell hung a small transmitter above the antenna to give every patch the same timing reference, and each patch corrected its own received timing back to what a perfectly flat antenna would see.
• CLM-1432 Rockwell's chart puts a price in mass on a flatter antenna. The frame for the 1,000 m radius weighs about 85 tonnes if it may deviate by 48 cm and about 226 tonnes if only 12 cm is allowed. The 500 m frame goes from about 16 to about 30 tonnes over the same range.

Cite this