The European Space Agency still does not know the fate of its Schiaparelli lander, the ExoMars spacecraft that attempted to land on surface of Mars this morning. Signals from the lander cut out just before it reached the ground, and ESA has yet to reestablish communication with the vehicle. Its abrupt silence sparks fears that it did not survive its high-speed fall to Mars — what ESA referred to as "six minutes of terror." Schiaparelli was equipped with a heat shield, a supersonic parachute, and a series of thrusters to help slow its fall and touch down gently on the Martian surface, but whether or not that engineering worked is still not known.

ESA is still holding out hope that the lander survived, though Paolo Ferri, head of ESA operations, said the lack of communication was not a good sign. The agency promised to work through the night and update everyone on the status of the lander at a press conference tomorrow at 4AM ET.

It's still been a success for the ExoMars mission

Even if Schiaparelli did crash, it's still been a success for the ExoMars mission — a partnership between ESA and Roscosmos to search for signs of life on the Red Planet. The venture had two goals today: land Schiaparelli and put a spacecraft called the Trace Gas Orbiter (TGO) into orbit around Mars. And the TGO pulled off its job flawlessly. Starting at 9:04AM ET, the orbiter burned its engine for more than two hours, putting the vehicle into a highly elliptical path around Mars.

A rendering of the Trace Gas Orbiter inserting itself into orbit. (ESA)

But as ESA celebrates the TGO's success, they will continue to search for answers about what happened to Schiaparelli. The lander began its descent at 10:42AM ET and seemed to go through its landing process just fine. During the vehicle's descent, an array of telescopes in India, called the Giant Metrewave Radio Telescope, picked up signals from Schiaparelli to help confirm that all went according to plan. Thanks to the telescopes, ESA determined that the vehicle had deployed its parachute and fired its thrusters as expected. But the spacecraft's signals cut out just before Schiaparelli should have landed, leaving ESA in the dark about whether or not the lander had survived the fall.

The spacecraft's signals cut out just before Schiaparelli should have landed

ESA hoped to get better confirmation of the state of the lander around two hours later, thanks to ESA's Mars Express — a spacecraft already in orbit around Mars. The orbiter recorded Schiaparelli's entire landing but couldn't send that info to Earth right away. And when the the orbiter did send back data to flight controllers on Earth, ESA said the information was inconclusive. Now, the next best bet will be from the TGO, which was also receiving signals from Schiaparelli during its fall. But that orbiter grabbed a lot of data about the descent, and that will take a while to send back to Earth.

ESA and Roscosmos knew that safely landing Schiaparelli would be tough. The lander entered the Martian atmosphere at a whopping 13,000 miles per hour, and Mars has a much thinner atmosphere than Earth's, making it hard for incoming spacecraft to slow down and not slam into the planet's surface. Because of this, many of Schiaparelli's predecessors did not survive the fall to Mars; only about 30 percent of Mars landers have ever successfully made it to the surface and still worked.

A rendering of the Schiaparelli lander with its parachute. (ESA)

But the ExoMars team tried to prepare Schiaparelli for its difficult journey to the ground. Once it entered the atmosphere, the lander used a variety of tools to slow itself down enough to land somewhat gently on the planet's surface. A heat shield protected the vehicle from intense temperatures during the first three minutes of its free fall, as the atmosphere helped to slightly cushion the spacecraft. Schiaparelli then deployed a supersonic parachute to further reduce its speed and then ignited a series of small thrusters to control the rest of its fall. Eventually, the thrusters were turned off and the lander dropped to the ground. It was at around this point that Schiaparelli's signals cut out.

No matter what happens, ESA views today's events as a success. Mars has a new orbiter, and Schiaparelli's landing was merely a demonstration mission, meant to pave the way for the next phase of the ExoMars mission in 2020. That part of the mission will attempt to land a rover on Mars, and Schiaparelli's landing will better ensure that the rover's landing is ultimately a success. But first, we need to find out what happened.