The inner satellite of Mars, 9376 km from the planet’s centre and only 6000 km above its surface. Phobos orbits in 0.319 days, faster than Mars rotates on its axis, keeping one face turned permanently towards the planet. Phobos is irregularly shaped, 26 × 23 × 18 km in size, and is covered with impact craters, the largest, Stickney, being 9 km in diameter. There are also several families of parallel grooves or chains of craters, possibly secondary craters from large impacts on Mars. Phobos was discovered in 1877 by A. Hall, and may be a captured asteroid.
http://www.esa.int/spaceinimages/Images/2009/12/Phobos_up_close
Either of two of Soviet spacecraft launched towards Mars in July 1988 to land on Phobos, one of the planet's two moons. Communication was lost with Phobos 1 before it reached Mars. Phobos 2 went into orbit around Mars in January 1989 but contact was lost on 27 March when it had approached to within 800 km/497 mi of Phobos.
1. Two Soviet missions to Mars, launched in 1988; both were lost.
2. One of the two satellites of Mars.
http://nssdc.gsfc.nasa.gov/planetary/phobos.html An RSA mission to study the Sun, Mars, and Phobos, a moon of Mars.
- duration
- Durbar
- Durbin, James (1923–2012)
- Durbin–Watson statistic
- Durbin–Watson test
- Durbin’s test
- duric horizon
- duricrust
- duripan
- durisols
- Durkheim, Émile (1858–1917)
- durophagic
- du Sautoy, Marcus (1965–)
- dust
- Dust Bowl
- dust-bowl
- dust cloud explosion
- dust core
- dust detection instrument
- dust detector
- dust devil
- dust storm
- dust tail
- Dutch auction
- Dutch book