... 3 Seasons of the year and inclination of the Earth's axis. ... 6 Calendar: solar and sidereal day . ... 9 Retrograde motion of inner and outer planets. ... Center of motion is not Sun but mutual center of gravity. 12a Concept of solving an equation by iteration [see M-2 for "Algorithm"] . ... 17 Concept of mass--gravitational vs. inertia. ... 25 Concept of center of gravity . Principle of rocket motion. ... 8 Size of Earth as estimated by the ancients and by Columbus. 8a The story of Pike's Peak. ...

... The gravity-gradient force on the Moon. 4b Craters of the Moon--why round, why middle higher. ... Intuitive concept of 2nd law--planet or satellite slows down when further away, relation to conservation of energy and analogy to motion of thrown stone. 12a Example of non-algebraic equation (Kepler's) . ... Principle of rocket motion. ... Design of house windows, taking advantage of the Sun's motion. 4a Poem by Vachel Lindsay. 4b The story of exploration of the Moon using space vehicles. ...

... In spite of the fact that the orbit assumes a zero gravity (the scientists count on it by growing super-clean crystals and other materials impossible on the earth), in fact, none spacecraft provides such conditions. ... This question is answered by the device developed by SSAU scientists - Micro-acceleration Compensation Space System (MCSS). ... Then, the computer will give commands to the magnets that compensate micro-accelerations. ... Tags: 'photon-m4' mcss . ... SAMARA STATE AEROSPACE UNIVERSITY...

... Solar System . ... Comets and Asteroids . ... Vision of Vesta: a dark feature with a diameter of approximately 100 kim near the asteroid's equator can be seen in this image from Dawn (Image credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA) . Between Mars and Jupiter lies the Asteroid Belt. ... The Dawn space probe is expected to go into orbit around Vesta on 16 July, from there it will return some detailed images and other data, staying at the asteroid for about a year before setting off to visit Ceres. ...

... How much brighter is the Sun as viewed from the planet Mercury as compared to Earth ? ... Actually, all of these questions can be answered through a very simple mathematical relationship known as the inverse square law. ... As the distance from the Sun increases the surface area of the sphere grows by the square of the distance. ... Common sense tells us that the Sun will be brighter and the inverse square law tells us how much brighter. ... gr = 0.912 G or 91.2% gravity felt at Earth's surface. ...

... The force F of gravity between two objects of mass m and M, whose centres are a distance r apart, is given by Newton's famous equation: [pic], where G = 6.67(10-11 N m2 kg-2, and F is measured in Newtons. So, the force in orbit Fo is weaker than the force on the Earth's surface F0 by the ratio: [pic] where the radius of the Earth is 6,400 km, and the orbit is 1000 km above the Earth's surface. ... Energy Considerations Another way to see all this is to consider the energy of an object in orbit. ...

... GRACE Maps the Gravity of Earth . ... 23.07.2003 . ... To help better understand the Earth's surface , slight distance changes between a pair of identically orbiting satellites named GRACE have been used to create the best ever map of Earth's gravitational field . ... Maps like this also help calibrate changes in the Earth's surface including variable ocean currents and the melting of glaciers . ... Publications with keywords: GRACE - Earth . Publications with words: GRACE - Earth . ...

GRANAT is the Russian x-ray sattelite launched to the high apogee orbit (200,000 km) and operated almost for 10 years (1989 -1999) , carrying out four major instruments: French SIGMA coded-mask hard x-ray telescope (30-1000 keV), Soviet ART-P coded-mask telescope (2??-60?? keV), all-sky monitor WATCH (6-150 keV), and a gamma-burst detector PHEBUS . ... Since September 1994, GRANAT is in the survey mode. ... Explore pages devoted to individual GRANAT instruments (including main scientific results): . ...

... Space flight . ... Space Hotel . ... Small orbital stations (SOS) are intended for the arrangement of flexible manned programs on commercial basis with the possibility of using the traditional Russian manned , cargo spacecrafts, their modifications and new modules oriented for the minimum costs and terms of orbital objects development . оThe principle of SOS building is as follows: it is developed not as a separate self-sufficient project of an ... It means a possibility of: . ...

... MAO main . ... Announcement : Conference on AUTONOMOUS SPACECRAFT NAVIGATION - New Concepts, Technologies & Applications for the 21st Century . ... От: Heraeus announcements . ... Тема: Announcement : Conference on AUTONOMOUS SPACECRAFT NAVIGATION - New Concepts, Technologies Applications for the 21st Century . This announcement was send to several email lists. ... AUTONOMOUS SPACECRAFT NAVIGATION . New Concepts, Technologies Applications for the 21st Century . ...

With this knowledge of orbits, we are ready to plan a trip to Mars. ... The spacecraft will already have the 107,000 kilometers per hour (66,500 miles per hour) speed of Earth, whereas Mars moves at only 86,900 kilometers per hour (53,900 miles per hour). ... A speed of about 42,000 kilometers per hour will be enough to escape the Earth's gravity and, when added to the Earth's orbital speed around the Sun, put the spacecraft on a Hohmann transfer orbit to the Red Planet. ... 1,570,000 . ... Earth . ...

... 2003 July 23 . GRACE Maps the Gravity of Earth . Credit: GeoForschungsZentrum Potsdam , CSR U. Texas , JPL , NASA . ... To help better understand the Earth's surface , slight distance changes between a pair of identically orbiting satellites named GRACE have been used to create the best ever map of Earth's gravitational field . ... Maps like this also help calibrate changes in the Earth's surface including variable ocean currents and the melting of glaciers . ... About APOD | ...

... NASA spacecraft to enter large asteroid's orbit July 16 . ... On July 16, NASA's Dawn spacecraft will begin a prolonged encounter with the asteroid Vesta, making the mission the first to enter orbit around a main-belt asteroid. ... Unlike other missions, where dramatic propulsive burns put spacecraft into orbit around a planet, Dawn will ease up next to Vesta. ... NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera July 9, 2011. ...

THE STUDY OF THE PIONEER ANOMALY THE STUDY OF THE PIONEER ANOMALY The Pioneer Anomaly : Effect, New Data and New Investigation Slava G. Turyshev Jet Propulsion Laboratory, California Institute of Technology Seminar at the Sternberg Astronomical Institute Moscow State University, Moscow, 6 February 2007 1 THE STUDY OF THE PIONEER ANOMALY THE STUDY OF THE PIONEER ... Are they relevant to the Pioneer anomaly? ...

... These trajectories have an initial flight from the Earth to a large distance (of about 1.5 million km), the following passive flight to the Moon's orbit, an approach to the Moon with a decrease of an energy of a particle (spacecraft) selenocentric motion to a negative value and the temporary capture in an elliptic orbit of the Moon's satellite. ... Several trajectories of this type are determined. ... Ivashkin V. V. On optimal trajectories of space flight to the Moon in the Earth--Moon--Sun system. ...

From Herschel's catalog, the first accurate stellar parallax measurement of 0.32 seconds of arc for the star 61 Cygni was published by the F.W. Bessel in 1838. ... This distance is equivalent to 3.26 light years. ... The Universe was now a large place and the intrinsic energy output of the stars had to be huge in order that their light could reach us. ... An Orbit in Curved Space This is a prediction made by General Relativity and confirmed by direct observation of Mercury. ...

... Impact on source motion in Galactic coordinate system is given by Kovalevsky (2003), Malkin (2011) l cos b = -A sin l, b = -A cos l sin b, where A = R0 02 /c is the galactocentric acceleration called hereafter the GA constant. ... We just have to return to the traditional many-centuries-old astrometric practice of modelling the position of a celestial object as a linear trend with two parameters: the position at the initial (conventional) epoch and the apparent (proper) motion. ... 2011). ...

... Ever since K.Tsiolkovsky laid theoretical foundations for a method to break the bonds of Earth's gravity and reach space, the dream of flying to other planets in our Solar System graduated from the realm of pure fantasy into a field of practical activities. ... Design work on manned mission to planet Mars which, among all the planets in our Solar System, has environments that are closest to those of Earth, started at RSC Energia almost as early as the work on first manned spaceflights. ...

... Posts tagged ?distance estimation? ... Since I began to subscribe arxiv/astro-ph abstracts, from an astrostatistical point of view, one of the most frequent topics has been photometric redshifts . ... Tags: cosmology , distance estimation , Lutz-Kelker bias , machine learning , Malmquist bias , Photometric Redshift , spectrum , survey , VO . ... Comment . ... Entries RSS . Comments RSS . ... General comments . ... vlk on [MADS] Parallel Coordinates . ... Entries (RSS) and Comments (RSS) . ...

... Bad Astronomy . ... Every few months, one of a series of questions comes up on the USENET group sci.astro involving tides, or the rotation of the Moon, or the recession of the Moon from the Earth. ... Why the Moon's rotation period is the same as the length of time it takes to orbit the Earth (same as number 1, but phrased differently). ... But when this happens, the time it takes for the Earth to rotate once will be slowed to exactly the same time it takes for the Moon to go around the Earth once! ...