The Ancient Mariner and the transit of Venus.
The achievements of William Wales FRS - astronomer, classical scholar, demographer, editor, mathematician, meteorologist and humane teacher - have been overshadowed by the fame of Cook's extraordinary voyages, and overlooked as a significant influence on Samuel Taylor Coleridge's early development. The Royal Society sent Wales to Hudson Bay, Canada, and James Cook to Tahiti, both to observe the 1769 transit of Venus as part of an international project to calculate solar parallax, and hence the distance to the Sun. Wales later taught mathematics and navigation science at Christ's Hospital School to a precocious Coleridge, whose creative mind translated tales of polar adventures into memorable poetry.
The Hudson's Bay Company and its critics in the eighteenth century
As the Hudson's Bay Company prepares to celebrate its tercentenary it is not mere academic perverseness which prompts a paper on a period in the Company's history when it was threatened with extinction. Longevity has its own fascination, and crucial in the story of the Company's growth into one of the great business enterprises of the modern world was its survival amid the bitter criticism directed at chartered companies in the eighteenth century. Small and apparently vulnerable, it showed unexpected stubbornness in resisting attacks which overwhelmed several of its fellows. The controversies which buffeted the Hudson's Bay Company also help to illuminate those mercantile pressure groups working against monopolies in the mid-eighteenth century, and reveal something of the friction at home which accompanied the steady expansion of British commerce overseas.
Space Qualification Testing of a Shape Memory Alloy Deployable CubeSat Antenna
Abstract : Increasingly capable CubeSat missions require antenna with improved Radio Frequency performance over the traditional CubeSat antennas. Deployable quadrifilar helical antennas (QHA) enable an acceptable stowing volume and deploy to provide increased gain and bandwidth over traditional patch and dipole antennas. Extensive ground testing is required to ensure the antenna is space qualified and to characterize the antenna deployment in the space environment. AFIT requires a QHA to perform a future CubeSat geolocation mission and contracted Helical Communication Technologies (HCT) to design and manufacture a Shape Memory Alloy (SMA) L-band deployable QHA. Vibration, thermal vacuum, laser vibrometer, and Voltage Standing Wave Ratio (VSWR) experiments were conducted on the HCT antenna to verify the hardware in a simulated launch environment and to characterize the SMA deployment in the simulated space environment.The HCT QHA successfully passed all required NASA General Environmental Verification Standards space qualification testing. Several anomalies experienced by the QHA encourage a redesign. The deployed antenna length varied from 250-290 mm and future RF testing is required to determine if the antenna geometry variations are significant enough to impact the geolocation mission.This research documents the test results for a QHA deployable CubeSat antenna testing and aids the development of CONOPS for the future AFIT CubeSat mission utilizing the HCT QHAs.