kwan@smeagol.UUCP (Richard Kwan) (01/25/86)
(Before someone in authority discovers my errors and chastises me...) A few weeks ago, I mentioned that Galileo and Magellan will be equipped with radiation-hardened RCA 1802 processors when they fly to Jupiter and Venus, respectively. Those ain't very powerful processors. I suggested to someone, wouldn't be nice if the craft had an on-board star catalog, and had enough on-board intelligence to recognize the stars in figuring its position? That, in fact, is what happens, I was told. A separate bit-slice design with floating point capability (including sines and cosines) is used to compute orientation for attitude control and depends on recognizing a number of objects. The design dates back to Voyager. Rick Kwan JPL Spacecraft Data Systems group P.S.: I've been having a hard time trying to track all this info down, so don't take this as authoritative. However, I think my sources are reliable.
doug@escher.UUCP (Douglas J Freyburger) (01/27/86)
->Discussion about using Rad-hard RCA 1802's on Galileo and ->also some bit-slice processors, to by Rick Kwan, JPL Spacecraft ->Data Systems group When I was in one of the VLSI design groups doing a Mariner Mark II chip at JPL, one of the things we were constantly told about was how 3 different companies did rad-hard 2901's for use on Galileo. The 2901 is a 4-bit machine used in all sorts of bit-slice designs. Galileo is carrying over a dozen each of 1802s and 2901s. RCA, Sandia, and "I forgot" did the Galileo chips. The Mariner Mark II series will carry 80C86 or 32C016s most likely. The 1802 and 2901 are very dependable machines, but are hard to use. It demostrates the NASA can't afford to fix it beyond Earth orbit. Remember that the 1802 was the latest and greatest about 10 years ago and it will be about 10 years until today's latest and greatest is reliable enough to launch. -- Doug Freyburger DOUG@JPL-VLSI, JPL Mail Stop 23 escher!doug, escher!teleop!doug Pasadena, CA 91109 etc. <Generic Disclaimer>