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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 ...
Many astronomical phenomena viewed from the planet Mars are the same as or similar to those seen from Earth; but some (e.g. the view of Earth as an evening/morning star) are quite different. For example, because the atmosphere of Mars does not contain an ozone layer, it is also possible to make UV observations from the surface of Mars.
Orbital elements are the parameters required to uniquely identify a specific orbit. In celestial mechanics these elements are considered in two-body systems using a Kepler orbit . There are many different ways to mathematically describe the same orbit, but certain schemes are commonly used in astronomy and orbital mechanics .
Artist's rendition of Mars Express as seen by NASA's Mars Global Surveyor Image of Mars Express in orbit at Mars. 2001 Mars Odyssey was launched April 7, 2001 on a Delta II rocket and currently holds the record for the longest-surviving continually active spacecraft in orbit around a planet other than Earth at 23 years, 3 months and 28 days. [4]
Mars Orbital Laser Altimeter (MOLA) colorized shaded-relief maps showing elevations in the western and eastern hemispheres of Mars. (Left): The western hemisphere is dominated by the Tharsis region (red and brown). Tall volcanoes appear white. Valles Marineris (blue) is the long gash-like feature to the right.
Orbit modeling is the process of creating mathematical models to simulate motion of a massive body as it moves in orbit around another massive body due to gravity.Other forces such as gravitational attraction from tertiary bodies, air resistance, solar pressure, or thrust from a propulsion system are typically modeled as secondary effects.
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.
Solid planets up to thousands of Earth masses may be able to form around massive stars (B-type and O-type stars; 5–120 solar masses), where the protoplanetary disk would contain enough heavy elements. Also, these stars have high UV radiation and winds that could photoevaporate the gas in the disk, leaving just the heavy elements. [62]