The Impact of the Yarkosvky Effect on Satellite Navigation around Small Bodies

2021 ◽  
Author(s):  
Quinn Lamey ◽  
Leonard D. Vance ◽  
Jekan Thangavelautham
Keyword(s):  
Satellite Navigation ◽  
Small Bodies ◽  
The Impact

scholarly journals Strategy for NEO follow-up observations

2012 ◽  
Vol 10 (H16) ◽  
pp. 185-185
Author(s):  
Milos Tichy ◽  
Michaela Honkova ◽  
Jana Ticha ◽  
Michal Kocer
Keyword(s):  
Small Bodies ◽  
Time Uncertainty ◽  
The Earth ◽  
Observation Strategy ◽  
On Line ◽  
Single Night ◽  
Uncertainty Map ◽  
The Impact ◽  
Near Earth Objects

AbstractThe Near-Earth Objects (NEOs) belong to the most important small bodies in the solar system, having the capability of close approaches to the Earth and even possibility to collide with the Earth. In fact, it is impossible to calculate reliable orbit of an object from a single night observations. Therefore it is necessary to extend astrometry dataset by early follow-up astrometry. Follow-up observations of the newly discovered NEO candidate should be done over an arc of several hours after the discovery and should be repeated over several following nights. The basic service used for planning of the follow-up observations is the NEO Confirmation Page (NEOCP) maintained by the Minor Planet Center of the IAU. This service provides on-line tool for calculating geocentric and topocentic ephemerides and sky-plane uncertainty maps of these objects at the specific date and time. Uncertainty map is one of the most important information used for planning of follow-up observation strategy for given time, indicating also the estimated distance of the newly discovered object and including possibility of the impact. Moreover, observatories dealing with NEO follow-up regularly have prepared their special tools and systems for follow-up work. The system and strategy for the NEO follow-up observation used at the Klet Observatory are described here. Methods and techniques used at the Klet NEO follow-up CCD astrometric programme, using 1.06-m and 0.57-m telescopes, are also discussed.

Organics In Comets

1997 ◽  
Vol 161 ◽  
pp. 121-142 ◽  
Author(s):  
Michael J. Mumma
Keyword(s):  
Recent Progress ◽  
Current Knowledge ◽  
Cometary Nucleus ◽  
Quantitative Chemical Analysis ◽  
Organic Fraction ◽  
Small Bodies ◽  
Organic Composition ◽  
Giant Impacts ◽  
Living Species ◽  
The Impact

AbstractThe birth-endowed organic fraction of the newly formed (hot) Earth was destroyed by thermal decomposition during the cooling epoch. After Earth cooled sufficiently, an early organic inventory was likely replenished by the impact of comets and asteroids — a process which continues even today. The present organic composition of comets and asteroids can provide information relevant to this secondary organic seeding of the planets, for comparison with scenarios leading to self-replicating organic entities. Although impacts no longer deliver organics in significant quantities, compared with the existing terrestrial inventory, small bodies can deliver their organics intact to Earth‘s surface while giant impacts may cause punctuated extinction of living species (and create opportunities for renewed speciation). Hence, the exogenous organic flux has great importance for life’s origins and terminations. Current knowledge of the organic composition of comets is reviewed, and recent progress in our understanding of the chemical evolution of organic material from its formation to its incorporation into comets and later into planets is outlined. The need for detailed quantitative chemical analysis of material obtained directly from the cometary nucleus is indicated.

Asteroseismology: The Impact of Solar Space Observations

1993 ◽  
Vol 137 ◽  
pp. 43-50
Author(s):  
H.S. Hudson
Keyword(s):  
Solar Flares ◽  
Coronal Holes ◽  
Magnetic Activity ◽  
Solar Interior ◽  
Small Bodies ◽  
Solar Observations ◽  
Global Properties ◽  
Stellar Convection ◽  
Technical Report ◽  
The Impact

AbstractObservations from space relevant to solar global properties (oscillations, magnetic activity, etc.) are helpful both scientifically and technically in preparing for stellar observations. This paper summarizes the results from the main previous experiments (ACRIM, SOUP, and IPHIR), and also give an initial technical report from the SXT instrument on board Yohkoh, launched in August 1991. The solar observations to date demonstrate the existence of several mechanisms for low–level variability: spots, faculae, the photospheric network, granulation, and p–mode oscillations. The observations of oscillations have been particularly helpful in setting limits on solar interior rotation. In addition to the solar processes, stars of other types may have different mechanisms of variability. These may include the analogues of coronal holes or solar flares, modes of oscillation not detected in the Sun, collisions with small bodies, duplicity, and probably mechanisms not invented yet but related in interesting ways to stellar convection and magnetism.

scholarly journals Variation in total electron content with sunspot number during the ascending and maximum phases of solar cycle 24 at Birnin Kebbi

2018 ◽  
Author(s):  
Aghogho Ogwala ◽  
Emmanuel Olufemi Somoye ◽  
Olugbenga Ogunmodimu ◽  
Rasaq Adewemimo Adeniji-Adele ◽  
Eugene Oghenakpobo Onori ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Total Electron Content ◽  
Local Time ◽  
Satellite Navigation ◽  
Electron Content ◽  
Total Electron ◽  
June Solstice ◽  
December Solstice ◽  
Radio Signals ◽  
The Impact

Abstract. Satellite radio signals are affected by the presence of electrons in the earth’s upper atmosphere (ionosphere). The more electrons in the path of the satellite radio signals, the more the impact on the accuracy of satellite navigation systems such as the Global Positioning System (GPS)/ Global Navigation Satellite System (GNSS) and GLONASS. These electrons introduce several meters of error in position calculation. Total Electron Content (TEC) is used to monitor possible space weather impacts on satellite to ground communication and satellite navigation. TEC is modified in the ionosphere by changing solar Extreme Ultra-Violet (EUV) radiation, geomagnetic storms, and the atmospheric waves that propagate up from the lower atmosphere. Therefore, TEC depends on local time, latitude, longitude, season, geomagnetic conditions, solar cycle activity, and condition of the troposphere. A dual frequency GPS receiver located at an equatorial station, Birnin-Kebbi in Northern Nigeria (geographic location: 12.64° N; 4.22° E), has been used to investigate variation of TEC during the period of 2011 to 2014. We investigate the diurnal, seasonal and solar cycle dependence of GPS-TEC. The result shows that TEC increases from a minimum at 0400 local time (LT) to maximum daytime peak between 1300–1600 LT and then decreases to a minimum value after sunset for all the years. Slight post-noon peaks in the daytime maximum and post-sunset decrease and enhancement is observed in some months. We observed that TEC were higher in the equinoxes than the solstices only in 2012. Where as in 2011, September equinox and December solstice recorded higher magnitude followed by March equinox and lowest in June solstice. In 2013, December solstice magnitude was highest, followed by the equinoxes and lowest in June solstice. In 2014, March equinox and December solstice magnitude were higher than September equinox and June solstice magnitude. June solstice consistently recorded the lowest values for all the years.

Towards synergy of GNSS and InSAR mining deformation monitoring with Sentinel-1 data

2021 ◽  
Author(s):  
Damian Tondaś ◽  
Maya Ilieva ◽  
Witold Rohm ◽  
Jan Kapłon
Keyword(s):  
Time Series ◽  
Real Time ◽  
Laser Scanning ◽  
Large Scale ◽  
Ground Deformation ◽  
Dimensional Space ◽  
Satellite Navigation ◽  
Deformation Monitoring ◽  
North East ◽  
The Impact

<p>The determination of ground deformation may be carried out by applying various measurement methods such as levelling, laser scanning, satellite navigation systems, Synthetic Aperture Radar (SAR) and many others. In this work, we focus on the comparison of the deformation effects measured by Global Navigation Satellite Systems (GNSS) and satellite Interferometric SAR (InSAR) methods in the Upper-Silesian coal mining region (SW Poland).</p><p>An unquestionable advantage of GNSS technology is the possibility of continuous monitoring of deformations in three-dimensional space. Moreover, the evolution of real-time (RT) techniques such as: near real-time (NRT), ultra-fast NRT or RT allows to obtain a high precise position determination with a relatively slight latency (ranging from a few seconds to less than one hour). The limitation of the satellite navigation technology is the spatial range of the measurements. The deformation can only be observed at the point where the GNSS antenna is located. Furthermore, the acquisition, installation and maintenance of the equipment may also involve high costs.</p><p>In contrast to the GNSS technique, the InSAR methods enable measurement of the large-scale subsidence areas with possibility to use free products and software (e.g. Sentinel-1 and SNAP). The large-scale InSAR investigations provide a better overview of local terrain changes. Unfortunately, InSAR methods also have some limitations related to data acquisition technology:  </p><ul><li>a few days latency in acquiring a new image,</li> <li>insensitivity to changes in the northern component,</li> <li>acquiring deformation only in the LOS direction.</li> </ul><p>The main goal of this research is to analyse the deformation results obtained using GNSS and InSAR methods with respect to the capabilities and limitations of these two techniques. We investigated the level of agreement of eight GNSS and InSAR time series in areas with no subsidence, together with results acquired on seven regions of mining deformation where the maximum subsidence velocity exceeds 50 cm/year. The mean RMS time series fitting error obtained in subsidence basin is more than 5 cm and in non-deformed areas is equal to 2 cm. The study also investigated the effect of coherence threshold levels (0.3 ÷ 0.6) with introduction of the northern GNSS component on the InSAR decomposition process. Assuming the same GNSS deformation value in each directions (north, east, and up), the impact of the northern component was estimated as 10% of the total LOS subsidence.</p>

scholarly journals Effect of the Planetesimal Belt on the Dynamics of the Restricted Problem of 2 + 2 Bodies

2022 ◽  
Vol 12 (1) ◽  
pp. 424
Author(s):  
Govind Mahato ◽  
Ashok Kumar Pal ◽  
Sawsan Alhowaity ◽  
Elbaz I. Abouelmagd ◽  
Badam Singh Kushvah
Keyword(s):  
Restricted Problem ◽  
Equilibrium Points ◽  
Small Bodies ◽  
Existence And Stability ◽  
The Impact

In this paper, we study the existence and stability of collinear and noncollinear equilibrium points within the frame of the perturbed restricted problem of 2 + 2 bodies by a planetesimal belt. We compare and investigate the corresponding results of the perturbed and unperturbed models. The impact of the planetesimal belt is observed on collinear and noncollinear equilibrium points. We demonstrate that all equilibrium points are unstable, and we numerically investigate the noncollinear equilibrium points. Finally, we emphasize that the proposed problem is a credible model for describing the capture of small bodies by a planet.

scholarly journals Fragmentation of colliding planetesimals with water content

2014 ◽  
Vol 9 (S310) ◽  
pp. 138-141 ◽  
Author(s):  
Thomas I. Maindl ◽  
Rudolf Dvorak ◽  
Christoph Schäfer ◽  
Roland Speith
Keyword(s):  
Brittle Failure ◽  
Escape Velocity ◽  
Small Bodies ◽  
Water Ice ◽  
Hit And Run ◽  
Impact Angles ◽  
The Impact ◽  
Insight Into ◽  
Water Contents ◽  
Asteroid Families

AbstractWe investigate the outcome of collisions of Ceres-sized planetesimals composed of a rocky core and a shell of water ice. These collisions are not only relevant for explaining the formation of planetary embryos in early planetary systems, but also provide insight into the formation of asteroid families and possible water transport via colliding small bodies. Earlier studies show characteristic collision velocities exceeding the bodies' mutual escape velocity which—along with the distribution of the impact angles—cover the collision outcome regimes ‘partial accretion’, ‘erosion’, and ‘hit-and-run’ leading to different expected fragmentation scenarios. Existing collision simulations use bodies composed of strengthless material; we study the distribution of fragments and their water contents considering the full elasto-plastic continuum mechanics equations also including brittle failure and fragmentation.

Formation of Lunar Craters and Bright Rays as a Result of Meteorite Impacts

1962 ◽  
Vol 14 ◽  
pp. 415-418
Author(s):  
K. P. Stanyukovich ◽  
V. A. Bronshten
Keyword(s):  
Explosive Charge ◽  
The Moon ◽  
Meteorite Impacts ◽  
The Earth ◽  
Lunar Craters ◽  
The Impact

The phenomena accompanying the impact of large meteorites on the surface of the Moon or of the Earth can be examined on the basis of the theory of explosive phenomena if we assume that, instead of an exploding meteorite moving inside the rock, we have an explosive charge (equivalent in energy), situated at a certain distance under the surface.

The Geosciences Applied to Lunar Exploration

1962 ◽  
Vol 14 ◽  
pp. 169-257 ◽  
Author(s):  
J. Green
Keyword(s):  
Lunar Surface ◽  
Probable Mechanism ◽  
Point Of View ◽  
Lunar Exploration ◽  
Geological Model ◽  
Apply Geophysics ◽  
Surface Features ◽  
The Impact

The term geo-sciences has been used here to include the disciplines geology, geophysics and geochemistry. However, in order to apply geophysics and geochemistry effectively one must begin with a geological model. Therefore, the science of geology should be used as the basis for lunar exploration. From an astronomical point of view, a lunar terrain heavily impacted with meteors appears the more reasonable; although from a geological standpoint, volcanism seems the more probable mechanism. A surface liberally marked with volcanic features has been advocated by such geologists as Bülow, Dana, Suess, von Wolff, Shaler, Spurr, and Kuno. In this paper, both the impact and volcanic hypotheses are considered in the application of the geo-sciences to manned lunar exploration. However, more emphasis is placed on the volcanic, or more correctly the defluidization, hypothesis to account for lunar surface features.

Sign in / Sign up

Export Citation Format

Share Document