【Halinghing】

On Wednesday,Halinghing the European Space Agency, with Russia's help, attempted to land an experimental spacecraft on Mars.

It didn't go according to plan.

While the Schiaparelli lander seemed fine through most of its descent, mission managers lost its signal at a key moment during the landing attempt. The signal cut out just before the spacecraft's thrusters fired to bring it safely down to the red planet.

People on the ground still haven't been able to figure out exactly what happened to the Schiaparelli, but signs aren't good.

There's a chance the lander crashed, but it will take more analysis of information sent to Earth by the ESA's Trace Gas Orbiter -- the other half of the ExoMars mission -- that made it into Mars' orbit successfully on Wednesday.

However, if Schiaparelli truly is lost on Mars, it'll be in good company. Of the about a dozen robotic lander and rover missions launched to Mars, only seven have succeeded, and all of these lucky ones were launched by NASA (if you don't count a Soviet craft that successfully landed but only transmitted from the surface for 20 seconds in 1971).

The red planet is not an easy world to conquer, and humanity's string of failures proves it. Mars' thin atmosphere still provides some resistance for spacecraft attempting to fly down to the surface, but not enough to slow a probe completely. This means that engineers have had to come up with a litany of exceedingly difficult ways to try to land on Mars. And they don't always work.

Here are a few of the most spectacular Mars mission failures of all time.

The Mars 7 lander and orbiter

In the 1960s, the Soviet Union started sending flyby, orbiter and lander missions to Mars.

Nearly every one of them failed.

Aside from the short-lived Mars 3 lander in 1971, all Soviet-era landers and most orbiters or flyby missions launched by the country failed in some way before they could complete their missions.

The Mars 7 orbiter and lander mission, launched in 1973, failed in a spectacular fashion.

Mars 7 got off Earth without much trouble, reaching the red world in 1974, but due to some sort of issue, the lander separated from the orbiter earlier than expected, according to NASA.

"The early separation was probably due to a computer chip error which resulted in degradation of the systems during the trip to Mars," NASA said in a summary of the mission.

Because of that glitch, the two spacecraft were pushed off course and are now orbiting the sun instead of the red planet.

The lost Beagle 2 lander

The United Kingdom-built Beagle 2 lander was at the center of a cosmic mystery for more than a decade after it was lost on Mars during its landing attempt in 2003.

The lander successfully separated from the ESA's Mars Express orbiter -- which is still functioning well in orbit around Mars -- but during its descent to the red planet, mission controllers lost touch with the lander. Mission managers weren't sure if Beagle 2 landed softly or crashed into the planet.

In order to figure it out, researchers trawled through photos of the planet's surface, hunting for the little lander, but it remained lost for about 11 years until a NASA spacecraft revealed its fate.

The Mars Reconnaissance Orbiter managed to snap photos of the Beagle 2's landing spot, which seemed to show that the spacecraft did land well on Mars but didn't deploy properly, keeping it from transmitting data to Earth.

"My Christmas day in 2003 alongside many others who worked on Beagle 2 was ruined by the disappointment of not receiving data from the surface of Mars," Mark Sims, who worked on the Beagle 2 mission, said in a statement after the lost lander was found. "The images vindicate the hard work put in by many people and companies both here in the UK and around Europe and the world in building Beagle 2."

NASA's Martian failure: The Mars Polar Lander

While NASA has landed and operated its fair share of spacecraft on the surface of Mars in its day, the space agency also has red planet failures to its name.

The Mars Polar Lander, which launched to space in 1999, was lost after it got got to the red planet, even before landing.

A sensor onboard the spacecraft triggered the shutdown of the lander's engines when it thought the craft had landed on Mars.

It hadn't.

The Mars Polar Lander was actually about 40 meters, or about 131 feet, above the red planet at the time, speeding at 13 meters per second, according to NASA. If the engines shut off at that time, the spacecraft would have sped up to a velocity of about 22 meters per second on impact, far higher than the 2.4 meters per second expected for a soft touchdown on the planet.

"At this impact velocity, the lander could not have survived," a NASA report about the lander's failure reads.

Russia and China's failed Martian plans

Russia's Phobos-Grunt spacecraft wasn't bound for the Martian surface -- it was aiming for the planet's moon Phobos -- but it still didn't get very far before it failed.

The spacecraft was expected to travel to the red planet after its launch in 2011 and scoop up a sample of the moon before returning it back to Earth.

These kinds of missions are something of a holy grail for planetary scientists because they can actually analyze a real sample from an alien world without risking human life.

Ambitious, right? Well, although the mission itself sounds like something dreamed up in science fiction, its problems were distinctly more down-to-Earth.

"Cheap parts, design shortcomings, and lack of pre-flight testing ensured that the spacecraft would never fulfill its goals," Planetary Society co-founder Louis Friedman wrote in a 2012 blog post. "Its troubles became apparent a few hours after its launch, when it failed to fire thrusters to take it out of Earth orbit and on its way to Mars and its moon Phobos."

Phobos-Grunt, with the Chinese Mars orbiter mission Yinghuo-1 launched along with it, remained stuck in Earth's orbit after launch and eventually burned up in our atmosphere in 2012.