25,042 research outputs found
Orbit determination and control for the European Student Moon Orbiter
No full textThis paper presents the preliminary navigation and orbit determination analyses for the European Student Moon Orbiter. The severe constraint on the total mission Delta nu and the all-day piggy-back launch requirement imposed by the limited available budget, led to the choice of using a low-energy transfer, more specifically a Weak Stability Boundary one, with a capture into an elliptic orbit around the Moon. A particular navigation strategy was devised to ensure capture and fulfil the requirement for the uncontrolled orbit stability at the Moon. This paper presents a simulation of the orbit determination process, based on an extended Kalman filter, and the navigation strategy applied to the baseline transfer of the 2011-2012 window. The navigation strategy optimally allocates multiple Trajectory Correction Manoeuvres to target a so-called capture corridor. The capture corridor is defined, at each point along the transfer, by back-propagating the set of perturbed states at the Moon that provides an acceptable lifetime of the lunar orbit. (C) 2012 Elsevier Ltd. All rights reserved
Moon\u27s hardy trees & plants for every place & purpose
No full textGlenwood Nurseries: [catalog]:1904-1906? Moon\u27s t
Moon Phases, Mood and Stock Market Returns: International Evidence
No full textWe employ recent data from 59 international emerging and mature stock markets to provide new evidence of a lunar cycle (full and new moon) effect on their stock market returns. Using a TGARCH model, we further examine the linkages between efficient-market theory, calendar-related effects and investors' mood resulted from moon phases. The empirical results show significant full moon effects in 6 markets, and significant new moon effects in 8 markets. In line with the theory, we report significant positive effect of new moon on stock market returns in 5 cases (UK, Switzerland, Bangladesh, Chile and Cyprus), while a negative effect of full moon is reported for the case of Jordan only. In addition, we find that lunar effects are strongly influenced by the calendar anomalies (Monday effect and January effect); several markets -mostly emerging markets- show evidence of full/new moon effects as well as Monday/January effects (Bangladesh, Brazil, Chile, Tunisia, Belgium, Cyprus). Further, we prove that the lunar phases are stronger outside America. These findings are recommended to investors, financial managers and analysts dealing with international stock indices
Navigation analysis and manoeuvres design for the European Student Moon Orbiter
No full textThis paper presents the latest results on the navigation and orbit determination analysis of the European Student Moon Orbiter (ESMO). The paper contains an investigation into the required orbit determination accuracy to inject the spacecraft into an orbit around the Moon that can be maintained without control for at least six months. A new baseline transfer is proposed together with a navigation strategy which fulfil the stringent requirement on the total propellant budget available for this challenging mission
Optimal design of low-energy transfers to highly eccentric frozen orbits around the moon
No full textScheduled for launch in 2014-2015, the European Student Moon Orbiter (ESMO) offers the opportunity for University students across Europe to design and build a microsatellite. Through the use of an all-day-piggy-back launch opportunity, ESMO will exploit the relative benefits of a Weak Stability Boundary (WSB) transfer to reach the Moon. ESMO will then enter a highly elliptical frozen orbit, gathering high resolution images of the surface of the South Pole. This paper will present ESMO’s optimal WSB transfer and insertion into its desired orbit. Highly elliptical frozen orbits have the benefit of a low orbital insertion delta-V that is combined with no or very small long-term variations of eccentricity and argument of periapsis. This significantly reduces the requirements on orbit maintenance. Coupled with the mission & scientific requirements, a highly elliptical frozen orbit is considered to be the optimal orbit design for ESMO. Furthermore, an optimal multi-burn strategy for both Earth departure and lunar arrival is also added to the transfer. This is to minimise gravity losses, error in the navigation budget and to provide flexibility in the final launch date selection. ESMO is considered to be an ambitious mission design
Low-thrust trajectories design for the European Student Moon Orbiter mission
No full textThe following paper presents the mission analysis studies performed for the phase A of the solar electric propulsion option of the European Student Moon Orbiter (ESMO) mission. ESMO is scheduled to be launched in 2011, as an auxiliary payload on board of Ariane 5. Hence the launch date will be imposed by the primary payload. A method to efficiently assess wide launch windows for the Earth-Moon transfer is presented here. Sets of spirals starting from the GTO were propagated forward with a continuous tangential thrust until reaching an apogee of 280,000 km. Concurrently, sets of potential Moon spirals were propagated backwards from the lunar orbit injection. The method consists of ranking all the admissible lunar spiral-down orbits that arrive to the target orbit with a simple tangential thrust profile after a capture through the L1 Lagrange point. The 'best' lunar spiral is selected for each Earth spiral. Finally,comparing the value of the ranking function for each launch date, the favourable and unfavourable launch windows are identified
On the survivability and detectability of terrestrial meteorites on the moon
No full textMaterials blasted into space from the surface of early Earth may preserve a unique record of our planet's early surface environment. Armstrong et al. (2002) pointed out that such materials, in the form of terrestrial meteorites, may exist on the Moon and be of considerable astrobiological interest if biomarkers from early Earth are preserved within them. Here, we report results obtained via the AUTODYN hydrocode to calculate the peak pressures within terrestrial meteorites on the lunar surface to assess their likelihood of surviving the impact. Our results confirm the order-of-magnitude estimates of Armstrong et al. (2002) that substantial survivability is to be expected, especially in the case of relatively low velocity (ca. 2.5 km/s) or oblique (≤45°) impacts, or both. We outline possible mechanisms for locating such materials on the Moon and conclude that searching for them would be a scientifically valuable activity for future lunar exploration
Moon's hardy trees & plants for every place & purpose / the William H. Moon Co.
No full textAnnual Established 1872 by William H. Moon, incorporated in 1890. Purchased the Samuel C. Moon nursery in 1911. Located in Chesapeake City, Maryland, since 1989 under the leadership of John Pursell. The legacy of the nursery goes back to 1767, when James Moon sold apple and pear trees in what would become Bucks County, Pennsylvania. Moon's son Moses and grandson James continued selling fruit trees. By the mid-1800's, great grandson Mahlon Moon was growing trees full-time on 40 acres that he called Morrisville Nursery. In 1872 his sons William and James founded the William H. Moon Company. William was president of the Pennsylvania Horticultural Society, founder and first president of the National Nurserymen's Association, and an organizer of the Ornamental Growers' Association. William's sons Henry T. and J. Edward continued in the business. A Japanese beetle infestation, the death of J. Edward Moon and the stock market crash in the 1920's brought hard times, and the nursery went bankrupt in 1936. Most of the land went to real estate development, and Hiram Rickert purchased the rest and continued to operate a nursery as a "successor to Moon's." In the 1960's, Richard H. Washburn bought the land from Hiram Rickert for development, and Walter C. Flowers bought the Moon and Rickert names for a new business, and in 1971 revived the nursery. More company history available on the website at http://www.moonnurseries.com/history/index.html Description based on: 1908; title from cover
Moon's hardy trees & plants for every place & purpose / the William H. Moon Co.
No full textAnnual Established 1872 by William H. Moon, incorporated in 1890. Purchased the Samuel C. Moon nursery in 1911. Located in Chesapeake City, Maryland, since 1989 under the leadership of John Pursell. The legacy of the nursery goes back to 1767, when James Moon sold apple and pear trees in what would become Bucks County, Pennsylvania. Moon's son Moses and grandson James continued selling fruit trees. By the mid-1800's, great grandson Mahlon Moon was growing trees full-time on 40 acres that he called Morrisville Nursery. In 1872 his sons William and James founded the William H. Moon Company. William was president of the Pennsylvania Horticultural Society, founder and first president of the National Nurserymen's Association, and an organizer of the Ornamental Growers' Association. William's sons Henry T. and J. Edward continued in the business. A Japanese beetle infestation, the death of J. Edward Moon and the stock market crash in the 1920's brought hard times, and the nursery went bankrupt in 1936. Most of the land went to real estate development, and Hiram Rickert purchased the rest and continued to operate a nursery as a "successor to Moon's." In the 1960's, Richard H. Washburn bought the land from Hiram Rickert for development, and Walter C. Flowers bought the Moon and Rickert names for a new business, and in 1971 revived the nursery. More company history available on the website at http://www.moonnurseries.com/history/index.html Description based on: 1908; title from cover
Moon's hardy trees & plants for every place & purpose / the William H. Moon Co.
No full textAnnual Established 1872 by William H. Moon, incorporated in 1890. Purchased the Samuel C. Moon nursery in 1911. Located in Chesapeake City, Maryland, since 1989 under the leadership of John Pursell. The legacy of the nursery goes back to 1767, when James Moon sold apple and pear trees in what would become Bucks County, Pennsylvania. Moon's son Moses and grandson James continued selling fruit trees. By the mid-1800's, great grandson Mahlon Moon was growing trees full-time on 40 acres that he called Morrisville Nursery. In 1872 his sons William and James founded the William H. Moon Company. William was president of the Pennsylvania Horticultural Society, founder and first president of the National Nurserymen's Association, and an organizer of the Ornamental Growers' Association. William's sons Henry T. and J. Edward continued in the business. A Japanese beetle infestation, the death of J. Edward Moon and the stock market crash in the 1920's brought hard times, and the nursery went bankrupt in 1936. Most of the land went to real estate development, and Hiram Rickert purchased the rest and continued to operate a nursery as a "successor to Moon's." In the 1960's, Richard H. Washburn bought the land from Hiram Rickert for development, and Walter C. Flowers bought the Moon and Rickert names for a new business, and in 1971 revived the nursery. More company history available on the website at http://www.moonnurseries.com/history/index.html Description based on: 1908; title from cover
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