HPM%SU-AI@sri-unix.UUCP (01/14/84)
From: Hans Moravec <HPM@SU-AI>
BC-PATENTS-COLUMN
(BizDay)
By STACY V. JONES
c.1984 N.Y. Times News Service
WASHINGTON - Improved control of its communication satellites that
orbit around the world has been invented for the RCA Corp. Patent
4,424,948, assigned to the company, was granted this week to three
technical staff members. The system is called magnetic torquing.
One problem frequently encountered by spacecraft is nutation, or
undesirable wobbling, and another is the need to maintain proper
attitude, or pointing, of the craft. Magnetic torquing, an answer to
both problems, involves passing current through coils on the
satellite, which interacts with the earth's magnetic field. The roll
and yaw errors are minimized.
The inventors are Ludwig Muhlfelder and Kevin J. Phillips of the RCA
Astroelectronics Division in East Windsor, N.J., and Steven L.
Blasnik of Cambridge, Mass.
Since 1958, RCA has launched 82 satellites and 12 of them are still
in operation. Those most recently launched are called Satcoms, and
the invention has been installed in five of these. Space is leased to
various companies and is used for transmission of radio and
television programs, weather data and other information.karn@allegra.UUCP (Phil Karn) (01/15/84)
Funny how magnetic torquing has been used on dozens of non-RCA satellites over the past 25 years. AMSAT-Oscar-10, the amateur radio satellite launched last summer, uses it exclusively. I never thought somebody could patent the electric motor. Maybe I should try for one on the electromagnet. Phil
lmc@denelcor.UUCP (01/17/84)
Funny, but it seems to me that magnetic torquing has been around quite a while. Iremember that the DMSP satellites (Defense Meteorological Satellite Program) used 6 months of magnetic torquing to bring their second bird back out of the pitching that a malfunction after launch caused, and that was circa 1975. What gives? -- Lyle McElhaney (hao,brl-bmd,nbires,csu-cs,scgvaxd)!denelcor!lmc