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Mars comes closer to Earth more than any other planet save Venus at its nearest—56 million km is the closest distance between Mars and Earth, whereas the closest Venus comes to Earth is 40 million km. Mars comes closest to Earth every other year, around the time of its opposition, when Earth is sweeping between the Sun and Mars. Extra-close ...
On both Earth and Mars, these two precessions are in opposite directions, and therefore add, to make the precession cycle between the tropical and anomalistic years 21,000 years on Earth and 29,700 Martian years (55,900 Earth years) on Mars. As on Earth, the period of rotation of Mars (the length of its day) is slowing down.
In 1781, he estimated the rotation period of Mars as 24 h 39 m 21.67 s and measured the axial tilt of the planet's poles to the orbital plane as 28.5°. He noted that Mars had a "considerable but moderate atmosphere, so that its inhabitants probably enjoy a situation in many respects similar to ours".
The Hubble Space Telescope, the first large optical telescope in orbit, is launched using the Space Shuttle, but astronomers soon discovered that it is crippled by a problem with its mirror. A complex repair mission in 1993 allows the telescope to start producing spectacular images of distant stars, nebulae, and galaxies.
Several factors make placing a spacecraft into an areostationary orbit more difficult than a geostationary orbit. Since the areostationary orbit lies between Mars's two natural satellites, Phobos (semi-major axis: 9,376 km) and Deimos (semi-major axis: 23,463 km), any satellites in the orbit will suffer increased orbital station keeping costs due to unwanted orbital resonance effects.
Mars spins a little more quickly each year, according to data collected by NASA’s now-retired InSight lander. ... The instruments were used to track Mars’ rotation during the mission’s first ...
2005 – The Mars Exploration Rovers perform the first astronomical observations ever taken from the surface of another planet, imaging an eclipse by Mars's moon Phobos. [232] Annular eclipse of the Sun by Phobos as viewed by the Mars Curiosity rover (20 August 2013). 2005 – Hayabusa spacecraft lands on asteroid Itokawa and collect samples ...
Scientists are unsure what is causing subtle speeding up of Red Planet’s rotation – but they have some ideas