کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8143369 1523930 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Touchdown on Venus: Analytic wind models and a heuristic approach to estimating landing dispersions
ترجمه فارسی عنوان
دست زدن به ونوس: مدل های باد تحلیلی و یک رویکرد اکتشافی برای تخمین پراکندگی فرود
کلمات کلیدی
سیاره زهره، باد، مسیریابی فضاپیما، پراکندگی فرود
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فیزیک زمین (ژئو فیزیک)
چکیده انگلیسی
The 'landing ellipse' or region of uncertainty within which an unguided probe to Venus may be expected to land is calculated. The region can be usefully seen as the convolution of three different factors: an initial circular delivery uncertainty which is smeared at a grazing entry angle onto the planetary sphere, an along-track uncertainty due to atmospheric density and vehicle aerodynamic variations during hypersonic entry, and a descent dispersion due to uncertain and/or variable zonal and meridional winds. This decomposition allows the various contributions to be instructively exposed and conveniently traded-off, without conducting explicit entry and descent dynamics simulations. It is seen that for descent durations and delivery errors typical of past Venus missions, the zonal wind contribution (determined with an analytic fit to Pioneer Venus tracking data) generally dominates, causing a ~200 km E-W (99%) dispersion, with meridional dispersions being about 4 times smaller. However, when entry angles become shallower than about 8°, the along-track dispersions may dominate, with the resulting ellipse becoming longer or wider depending on the entry azimuth. The analytic wind descriptions presented here may be applied to scientific problems, such as the dispersal of volcanic plumes or impact ejecta.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Planetary and Space Science - Volume 108, April 2015, Pages 66-72
نویسندگان
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