Star tracker axis-to-sunlit earth horizon angle constraint evaluations for rendezvous operations

The results are presented of a study initiated to evaluate the star tracker axis-to-sunlit earth horizon angle constraint with respect to limitations imposed on the passive target rendezvous capability. The data presented include considerations for dispersions and sensor pointing capabilities and generalizations with respect to the uncertainties associated with the angle constraint available in practice

Rendezvous radar requirements analysis for mission 3B

Data are presented verifying the compatibility of currently proposed rendezvous radar measurement accuracies with Mission 3B rendezvous requirements. In addition, data presented indicate a potential for increasing the acceptable time lag between termination of thrusting and availability of accurate measurement data. Additional investigation is recommended to define any acceptable time lag above the current proposed value. Finally, Mission 3B rendezvous performance is shown to be sensitive to variations in the relative downrange position dispersions at insertion. It is therefore recommended that insertion relative state dispersions used in studies of 3B rendezvous be reviewed when results of 3B ascent dispersion studies are available

U.S. budget deficits and the real value of the dollar

Foreign exchange rates ; Dollar, American ; Fiscal policy ; Budget deficits

Transient engine simulation program. NERVA program

IBM 7094 transient engine simulation program for NERV

Impact of Simulated Insect Defoliation and Timing of Injury on Cabbage Yield in Minnesota

In 1992 and 1994, field studies were done to assess the tolerance of transplanted cabbage to simulated insect defoliation and to determine if the defoliation level and growth stage at which defoliation begins influences final yield. In both years, 6 defoliation levels ranging from 0-100% were applied to transplanted cabbage at 4 time intervals. The time intervals began at transplanting, pre-head and head stages and continued until either head stage or harvest. For both years, the only time interval with significantly higher yield than the trans- plant to harvest interval (longest interval) was the head to harvest interval (shortest interval) and significant yield loss occurred only when defoliation was \u3e12.5%. Results suggest that transplanted cabbage can withstand relatively low levels of defoliation before yield loss occurs but that yield loss is also related to the duration over which defoliation occurs. In early growth stages, to protect yield, pest management practices should focus on reducing the interval over which damage occurs. The use of cultural practices that delay the onset of defoliation or allow avoidance of pests could protect yield. These strategies may include using transplants to shorten the time from planting to harvest or using planting dates that allow significant plant growth (i.e., head stage) before defoliators are able to infest the crop and cause significant damage. In addition, management strategies that reduce pest populations can also protect yield but at the head stage should switch to managing pests to protect marketability by reducing aesthetic damage and head contaminants

Early-Season Phenology and Temporal Dynamics of the Common Asparagus Beetle, \u3ci\u3eCrioceris Asparagi\u3c/i\u3e (Coleoptera: Chrysomelidae), in Southern Minnesota

During the years 1991-1994, studies were conducted to determine the early-season phenology and temporal dynamics of Crioceris asparagi (L.) (Co- leoptera: Chrysomelidae) in southern Minnesota asparagus. To document the early-season phenology, asparagus plots were sampled for egg, larval, and adult stages of C. asparagi during the months of May and June. Temporal dynamics of C. asparagi were determined by measuring the diurnal activity of adults and sampling asparagus plots at specific times (7 am, 9 am, 11 am, 1 pm, 3 pm and 5 pm) throughout May and June. We first detected C. asparagi adults in early May and they remained active throughout the sampling period. Eggs and larvae were also found; larval infestations on spears, however, were consistently lower than those for eggs. The temporal dynamics of C. asparagi adults showed that a higher percentage of asparagus plants were observed to be infested with beetles during the afternoon hours of 1 and 5 pm. The information provided in this paper illustrates the importance of determining the optimum time of day for sampling and will assist in properly targeting sampling efforts in future asparagus research and integrated pest management (IPM) programs