From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: * X-Spam-Status: No, score=1.3 required=5.0 tests=BAYES_00,INVALID_MSGID, MSGID_RANDY autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,58ccdc162acdfc04 X-Google-Attributes: gid103376,public From: Ted Dennison Subject: Re: What language was used on Deep Space 1? Date: 1999/07/30 Message-ID: <7nsj4b$ks9$1@nnrp1.deja.com>#1/1 X-Deja-AN: 506933069 References: <37A12E5C.DD1F8720@easystreet.com> X-Http-Proxy: 1.0 x23.deja.com:80 (Squid/1.1.22) for client 204.48.27.130 Organization: Deja.com - Share what you know. Learn what you don't. X-Article-Creation-Date: Fri Jul 30 16:16:23 1999 GMT X-MyDeja-Info: XMYDJUIDtedennison Newsgroups: comp.lang.ada X-Http-User-Agent: Mozilla/4.6 [en] (WinNT; I) Date: 1999-07-30T00:00:00+00:00 List-Id: In article <37A12E5C.DD1F8720@easystreet.com>, Al Christians wrote: > JPL's Deep Space 1 probe just did quite well using an advanced > autopilot. JPL did use Ada on their Mars mission a little while > back. Did Deep Space 1 use it too? Can anyone here tell how this > software was built? It just so happens that I have a paper here that was required reading for my AI class titled "Smart Executives for Autonomous Spacecraft", written by Erann Gat of JPL and Barney Pell of NASA Ames Research Center. It was published in the September/October 1998 IEEE Intelligent Systems, for those who may be interested. The paper discusses the development of an executive for an autonomous spacecraft, dubbed "Remote Agent". According to the article, "RA's implementation language is Common Lisp. RA runs in Allegro Common Lisp under Unix and on the flight processor (a Rad6000--radiation-hardened processor similar to a PowerPC) under a custom port of Harlequin Common Lisp for the vxWorks real-time operating system." It appears that some sub-components of the Remote Agent were written in their own modelling languages that were built upon lisp. Since this is primarily an expert system problem, its not at all shocking to find that it was written in Lisp. I've gotten farily familiar with how forward-chaining inference engines operate thanks the the class project I've spent the better part of this week working on. It would be a fairly difficult thing to program directly in a procedural language. However there are some similarities between how an inference engine works and how a compiler works. Both are basicly in the business of matching expressions. I've given some thought to one day seeing if the OpenToken approch to providing compilation services to an Ada program could be used in the expert system domain as well. Anyway, it appears the project's homepage is http://ic-www.arc.nasa.gov/ic/projects/Executive/ . There are links to lots more papers there if you are interested. -- T.E.D. Sent via Deja.com http://www.deja.com/ Share what you know. Learn what you don't.