On Monday, the popular "Sarcastic Rover" Twitter account offered a succinct description for how difficult it is to launch a probe from Earth and place it safely on the surface of Mars: "Landing on Mars is like tossing a baseball from New York to Tokyo and having it drop into a can of soup. Also the can still has a lid on."

While we can't vouch for the scientific fidelity of the analogy, it seems apt, as many probes that try to land on Mars find a grave instead of a scientific wonderland. Four of the five Soviet landers sent to Mars failed to reach ground safely, and the one that did, Mars 3 in 1971, survived for only about 15 seconds. In 2003, Europe's Mars Express orbiter released the Beagle 2 lander, but its solar panels never fully deployed, and the vehicle never phoned home. Only NASA has had success; impressively, eight of its nine missions to the surface of Mars have made it.

Now Europe is trying again with its ExoMars mission, consisting of an orbiter and lander. On Wednesday morning at 10:42am ET (15:42 UK), the European Space Agency's 1.65-meter wide Schiaparelli lander will enter the Martian atmosphere and make a harrowing six-minute descent to the red planet's surface.

Schiaparelli will rely on its heat shield from an altitude of 121km down to about 11km above Mars, slowing from a speed of about 21,000km/h to 1,700km/h. At that point, its 12-meter parachute should deploy and slow the spacecraft further before nine hydrazine-powered thrusters arrest its descent to a few meters per second. A crushable structure will absorb the impact force at the planet's surface.

Schiaparelli is intended to land on the Meridiani Planum, a relatively smooth, flat region close to the equator in the southern highlands. Once on the surface, the probe's limited scientific package is designed to operate for a few days. The primary role of Schiaparelli will be to demonstrate this landing technology so that a planned follow-up mission in 2020, complete with a rover, can also safely reach the Martian surface.

The ExoMars program has been in various stages of planning for nearly two decades. In 2008, NASA and the European Space Agency finally reached an agreement to share costs on the two missions, as well as an orbiter and landers. Both missions would search for life and test technologies for a mission to return samples of Martian soil and rocks to Earth.

However, in February, 2012, President Obama's budget called for the cancellation of NASA's participation in the ExoMars program to pay for the James Webb Space Telescope, which continued to run over its budget allocation. At that point, the European Space Agency turned to Russia, which has long wanted to return to Mars after a series of missions in the 1970s. The Russians provided a Proton-M launch vehicle for the mission, as well as some of its scientific payload.

In addition to the lander, the Trace Gas Orbiter spacecraft will remain in orbit and attempt to detect a wide range of atmospheric trace gases, particularly methane. The Gas Orbiter's aim is to determine whether these molecules are formed by biological or geological activity. It should begin collecting high quality data next March. For now, all eyes are on Wednesday's harrowing descent.