Viking Meteorology Instrument System testing at NASA Langley Research Center

<P> A meteorology sensor test plan was developed by NASA Langley Research Center, LRC, TRW (the meteorology instrument supplier), and the Meteorology Team. Because TRW's proposed cost to enhance its Biology-Meteorology test set to provide adequate recording capabilities was $ 200,000, Jim Tillman proposed a UW test facility both to operate VMIS, and process its data. Department engineer Henry LaHore, Fred weller, and Tillman designed the interface and Tillman prepared the Request for Proposal and benchmarks for purchasing the computer. NASA LRC developed a cold CO₂ flow system for testing down to -70° C and obtained uique wind tunnel test resources. Testing of the Viking Meteorology Instrument System, VMIS was carried out in the NASA Langley Research Center's Transonic Dynamics Tunnel, TDT, one of the world's major wind tunnels. It is described in<A HREF="http://www.atmos.washington.edu/local-httpdocs/k12/viking_history_npug_84.html#meteorology_testing"> <B><I>this Viking overview</I></B></A>, along with Mars background information and the Viking Mission from a meteorological perspective. The significance of our developing the VCF for TDT testing can be garnered from the facts: 1) we were given a two week slot during 1975 in the TDT, 2) the <B>TDT's 1975 cost was $4,000/hour </B>, 3) the tunnel consumes 1.0 Million watts at idle, 4) is scheduled years in advance, and 5) we were allocated the F-18's scheduled time slot. In this environment, delays and problems were not an option. After completing testing in November of 1975, the system was moved back to UW from NASA Langley to help analyze test results that were incorporated into our Mission software. This was greatly facilitated by upgrading our VCF Prime 300 computer to a Prime 400, Serial # 2, the first major, virtual memory super-mini computer in early 1976. It easily ran programs hundreds of times larger than could be run on most mainframes of that era, including our JPL Viking Science Univac 1108 mainframe without ``overlaying''. This computer now belongs to the Boston Computer Museum. <P><A HREF="tdt_cutaway8_100.jpg" align ="left"> <IMG SRC=tdt_cutaway_half_size.jpg =left></A> <P> An idea of the size of the facility is illustrated by clicking on this image where the larger version illustrates the red silhouette of a fighter aircraft model shown via the cut away of the large subsection of the wind tunnel in the foreground. The rust red, box like structure surrounding the fighter is 16 feet wide while the long, teardrop wind tunnel motor with vanes at the rear, produces 20,000 horsepower at maximum power. The tunnel covers speeds from a few meters/second to transonic and pressures ranging from atmospheric to 1/100th of an atmosphere, Martian pressures.