On Monday, the popular Twitter account “Sarcastic Rover” appeared. offered a succinct description of how difficult it is to launch a probe from Earth and place it safely on the surface of Mars: “Landing on Mars is like throwing a baseball from New York to Tokyo and dropping it in a can of soup. The jug also has a lid on it.”
While we can’t vouch for the scientific reliability of the analogy, it seems apt, as many probes attempting to land on Mars find themselves in a tomb rather than a scientific wonderland. Four of the five Soviet landers sent to Mars failed to reach the ground safely, and the one that did, Mars 3 in 1971, only survived for about 15 seconds. In 2003, the European Mars Express orbiter released the Beagle 2 lander, but the solar panels never fully deployed and the vehicle never called home. Only NASA has had success; impressively, eight of the 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. At 10:42 a.m. ET (3:42 p.m. UK) on Wednesday morning, 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 relies on its heat shield from an altitude of 121 km to about 11 km above Mars, slowing from a speed of about 21,000 km/h to 1,700 km/h. At that point, its 40-foot (12-meter) parachute should deploy and slow the spacecraft further before nine hydrazine-powered thrusters halt its descent to a few feet per second. A compressible structure will absorb the impact force on the surface of the planet.
Schiaparelli is planned to land on the Meridiani Planum, a relatively smooth, flat area close to the equator in the southern highlands. Once on the surface, the probe’s limited science package is designed to operate for a few days. Schiaparelli’s primary role 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 surface of Mars.
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 the cost of the two missions, as well as an orbiter and landers. Both missions would search for life and test technologies for a mission to return Martian soil and rock samples 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 exceed its budget allocation. At that point, the European Space Agency turned to Russia, which had 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 science payload.
In addition to the lander, the Trace Gas Orbiter spacecraft will remain in orbit and attempt to detect a wide variety of atmospheric trace gases, particularly methane. The purpose of the Gas Orbiter is to determine whether these molecules are formed by biological or geological activity. It should start collecting high-quality data in March. For now, all eyes are on Wednesday’s harrowing descent.