BARRY@RICEVM1.BITNET (01/17/90)
In my original "Direct Ascent Trajectory" posting, it took great restraint to avoid using even more acronyms than I did. Here's what they were intended to mean (and a few others): AOA Abort Once Around AOS Acquisition of signal ATO Abort To Orbit ET External Tank HAC Heading Alignment Cone LOS Loss of signal/Line of sight MECO Main engine cutoff NASA Nasty Acronym Socety of America OMS Orbital Maneuvering System RCS Reaction Control System RTLS Return to Launch Site SRM Solid Rocket Motor SSME Space Shuttle Main Engine TAL Transatlantic Abort Landing * TIG Time of ignition * This is the currently accepted expansion of TAL. We use it in this way because back in 1985, when we were practicing for WTR (Western Test Range) launches from VAFB (Vandenberg Air Force Base), there was an equivalent launch abort mode over the Pacific, thus we have Transpacific Abort Landing, still called TAL. Some even prefer Transoceanic Abort Landing. There's a nice, out-of-date, book published by NASA describing the accepted use of any and all acronyms ever conceived. The best ones are those with Greek letters in them. ------------------------------------------------------------------------- Matthew R. Barry Department of Mechanical Engineering Guidance and Propulsion Systems Rice University NASA/Johnson Space Center DF63 Houston, TX 77252 Houston, TX 77058 barry@ricevm1.rice.edu mbarry@nasamail.nasa.gov -------------------------------------------------------------------------