Trip - What trips could be done from mars in a few days to nearby moons and what would you see?

What trips could be done from mars in a few days to nearby moons and what would you see?

what trips could be done from the planet mars in a few days to nearby moons and what would you see?

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Mars has two moons, Phobos and Deimos, Both are small, irregular in shape, orbit close to the planet, and are believed to be captured asteroids.

The innermost asteroids of the Main Asteroid Belt between Mars and Jupiter are considerably further away and whilst there are known Trojans co-orbiting with Mars at its Lagrange L4 and L5 points, they are a considerable distance away, too **. So for short excursions, space tourists will be rather stuck for choice. It is go to Deimos or go to Phobos. And that's it.

Phobos, the larger and innermost moon has dimensions of 27×21.6×18.8 km, a mass of 1.08×10^16 kilograms and a semi-major axis of 9, 377 km.

Deimos, the smaller and outermost moon, has dimensions of 10×12×16 km, a mass of 2×10^15 kilograms and a semi-major axis of 23, 460 km.

Both satellites were discovered in 1877 by Asaph Hall, and are named after the characters Phobos (panic/fear) and Deimos (terror/dread) who, in Greek mythology, accompanied their father Ares, god of war, into battle. Ares was known as Mars to the Romans.

If viewed from the surface of Mars near its equator, full Phobos looks about one third as big as the Earth's full moon from Earth. It has an angular diameter of between 8' (rising) and 12' (overhead). It would look smaller when the observer is further away from the Martian equator, and is completely invisible (always beyond the horizon) from Mars' polar ice caps.

Deimos looks more like a bright star or planet for an observer on Mars, only slightly bigger than Venus looks from earth; it has an angular diameter of about 2'. The Sun's angular diameter as seen from Mars, by contrast, is about 21'. Thus there are no total solar eclipses on Mars, as the moons are far too small to completely cover the Sun.

On the other hand, total lunar eclipses of Phobos are very common, happening almost every night.

The motions of Phobos and Deimos would appear very different from that of our own Moon. Speedy Phobos rises in the west, sets in the east, and rises again in just eleven hours, while Deimos, being only just outside synchronous orbit, rises as expected in the east but very slowly. Despite its 30 hour orbit, it takes 2.7 days to set in the west as it slowly falls behind the rotation of Mars, and has long again to rise.

Both moons are tidally locked, always presenting the same face towards Mars. Since Phobos orbits Mars faster than the planet itself rotates, tidal forces are slowly but steadily decreasing its orbital radius. At some point in the future, when it approaches Mars closely enough, Phobos will be broken up by these tidal forces.

Several strings of craters on the Martian surface, inclined further from the equator the older they are, suggest that there may have been other small moons that suffered the fate expected of Phobos, and also that the Martian crust as a whole shifted between these events.

Deimos, on the other hand, is far enough away that its orbit is being slowly boosted instead, as in the case of our own Moon.

The Martian atmosphere is so thin that there would not be a significant boost to viewing conditions with a telescope, on either of its moons, as compared to a telescope on the Martian surface. All that you would see by going on a day trip to one of the moons, that you cannot see from the surface of Mars is the dark side of the moon you visit. Hardly worth getting out of bed for, I would have thought!

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** For completeness. here are details of the trojans:

5261 Eureka was discovered at Mt Palomar Observatory on June 20, 1990 and turned out to be the first known Mars Trojan asteroid. It trails Mars (at the L5 point) at a distance varying by only 0.3 AU during each revolution (with a secular trend superimposed, changing the distance from 1.5-1.8 AU around 1850 to 1.3-1.6 AU around 2400).

Minimum distances from the Earth, Venus and Jupiter are 0.5, 0.8 and 3.5 AU, respectively.

Long-term numerical integration shows that the orbit is stable. Kimmo A. Innanen and Seppo Mikkola note that "contrary to intuition, there is clear empirical evidence for the stability of motion around the L4 and L5 points of all the terrestrial planets over a timeframe of several million years".

Since the discovery of 5261 Eureka, the Minor Planet Center has recognized three other asteroids as Martian Trojans: 1999 UJ7 at the L4 point, 1998 VF31 at the L5 point,[1] and 2007 NS2, also at the L5 point.

At least six other asteroids have been discovered which are in near 1:1 resonances with Mars, but fail to exhibit trojan behavior. They are 2001 FR127, 2001 FG24, 2001 DH47, 1999 ND43, 1998 QH56 and 1998 SD4.

The infrared spectrum for 5261 Eureka is typical of an A-class asteroid, but the visual spectrum is consistent with an evolved form of achondrite called an angrite. A-class asteroids are tinted red in hue, with a moderate albedo. The asteroid is located deep within a stable Lagrangian zone of Mars, which is considered indicative of a primordial origin—meaning the asteroid has most likely been in this orbit for much of the history of the solar system.