Space station orbiting Mars by Ville Ericsson

Picture of the Day 28/2/2017 - An international space station orbiting Mars by Swedish concept artist Ville Ericsson.
More of his fantasy art here.

Space station in Mars orbit by Glenn Clovis

Picture of the Day 22/12/2016 - "Phoenix" space station in Mars orbit by sci-fi artist Glenn Clovis. More of his art here.

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Astronaut looking at Mars by Jean-Michel Trauscht

Picture of the Day 20/12/2016 - Astronaut looking at Mars from the orbit by Brazilian matte painter Jean-Michel Trauscht.
More of his art here.

Mars shuttle concept by Nenad Gojkovic

Picture of the Day 18/10/2016 - Mars surface to/from Low Mars orbit shuttle by Serbian concept artist Nenad Gojkovic. More of his concept art here.

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Fan visualization of Mars Colonial Transporter arriving at Mars

Mars Colonial Transporter concept by Richard Heidmann

Picture of the Day 31/7/16 - Concept art for SpaceX's Mars Colonial Transporter by Richard Heidmann from the French chapter of The Mars Society (Association Planète Mars). You can also read his speculations of the possible MCP mission architecture details here.

As the day the SpaceX CEO Elon Musk intends to unveil (at the International Astronautical Congress 26-30 September 2016 in Guadalajara, Mexico) details of its 'Mars Colonial Transporter' (MCT) mission architecture is nearing, we will mostly dedicate our 'Picture of the Day' awards to the fan concept art of the MCT.

Soviet lander on Phobos by Maciej Rebisz

Picture of the Day 30/5/16 - Soviet lander on Phobos by Polish sci-fi artist Maciej Rebisz. More of his art here and here.

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Astronauts on Phobos by Ron Miller

Picture of the Day 12/2/16 - Astronauts on Phobos by sci-fi illustrator and writer Ron Miller. More of his Mars art here.

5 spacecraft currently orbiting Mars

In a recent article "Traffic around Mars gets busy" the NASA/JPL summed up some facts about spacecraft currently orbiting Mars. The most interesting is the provided graphic of their orbits around Mars (together with planet's two natural satellites Phobos & Deimos):

So there are 5 active Mars orbiters currently orbiting the planet:

View from Mars orbit by Ludovic Celle

Picture of the Day 14/4/15 - View from the window of spaceship in Mars orbit by French graphic artist Ludovic Celle.
More of his Mars art here.

Spaceship in Mars orbit by Tim Flattery

Picture of the Day 23/2/15 - Spaceship in Mars orbit by Tim Flattery from his concept art for Mission to Mars. More of his concept art for movies here.

Entering Mars atmosphere by Manchu

Picture of the Day 15/6/14 - Mars habitat module entering Mars atmosphere with Low Density Supersonic Decelerator (LDSD) by French sci-fi artist Manchu (Philippe Bouchet).

Spaceship in Mars orbit by deckard01

Picture of the Day 23/4/14 - Spaceship in Mars orbit (2013) by computer graphics artist deckard01.