... With enough velocity, a spacecraft can break loose from the Earth's gravity and enter an orbit around the Sun, like that of a planet. If it then orbits the Sun with the same period as the Earth--one year--it may keep a fixed position relative to Earth. ... If the distance is just right--about 4 times the distance to the Moon or 1/100 the distance to the Sun--the spacecraft, too, will need just one year to go around the Sun, and will keep its position between the Sun and the Earth. ...

... With enough velocity, a spacecraft can break loose from the Earth's gravity and enter an orbit around the Sun, like that of a planet. If it then orbits the Sun with the same period as the Earth--one year--it may keep a fixed position relative to Earth. ... If the distance is just right--about 4 times the distance to the Moon or 1/100 the distance to the Sun--the spacecraft, too, will need just one year to go around the Sun, and will keep its position between the Sun and the Earth. ...

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 . ...

... Planets . ... Earth Satellites . ... Looking in the direction of the constellation Cygnus the Swan and launched by NASA in 2009 is the Kepler Space Observatory.Many previous missions searching for exoplanets mainly detected large giant planets, like large hot Jupiters (it is easier to detect larger planets).However KeplerтАЩs main objective is to search for much smaller planets located in a habitable zone which is not too close nor too far from their star; planets which may be just like our Earth. ...

NASA Press Release Text - June 24, 1996 GALILEO READY FOR CLOSE FLYBY OF JUPITER'S BIGGEST MOON Now residing in orbit around Jupiter, NASA's Galileo spacecraft is primed for its first close flyby of Jupiter's largest moon, Ganymede, at 2:29 a.m. EDT on June 27, 1996. ... In the days just before and after the Ganymede flyby, Galileo's other studies will include a search for auroral activity on Jupiter's nightside and observations of other Jovian moons: Io, Europa and Callisto. ...

... 24.12.1998 . ... Ring Around the Galaxy . ... By chance, a collision of two galaxies has created a surprisingly recognizable shape on a cosmic scale - "The Cartwheel Galaxy". The Cartwheel is part of a group of galaxies about 500 million light years away in the constellation Sculptor (two smaller galaxies in the group are visible on the right). ... This dramatic premier three-dimensional visualization of Mars' north pole is based on elevation measurements made by an orbiting laser. ... 1997 1998 . ...

... 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. ...

... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . Asteroid 2010 SO16 and the Earth follow similar orbits around . the Sun. ... out a horseshoe shape in space, taking 175 years to go from . ... Asteroid 2010 SO16 takes 175 years to make the trip from one end of the horseshoe to the other. ... Currently, three other horseshoe companions of the Earth are known to exist but, unlike 2010 SO16, these linger for a few thousand years at most before moving on to different orbits. ...

... Launch Date: 1968-09-14 . ... Zond 5 was launched from a Tyazheliy Sputnik in Earth parking orbit to make scientific probes during a lunar flyby and to return to Earth. ... The closest distance was 1,950 kilometers (1,212 miles). High-quality photographs of the Earth were taken at a distance of 90,000 kilometers (56,000 miles). ... On September 21, 1968, the re-entry capsule entered the Earth's atmosphere, braked aerodynamically, and deployed parachutes at 7 kilometers (4.35 miles) . ...