Unlike the doomed Beagle 2 mission that was lost in 2003, Schiaparelli transmitted its status data to its mother ship—the Trace Gas Orbiter—during its descent. As reported in Nature News, an early look at the data points to a series of cascading software errors as the reason for the botched landing.
By all accounts the descent started well, with the lander decelerating rapidly as it brushed up against the Martian atmosphere, eventually deploying its parachute as planned. But things began to go squirrely just prior to the five-minute mark of the planned six-minute descent.
For reasons that are still a mystery, the lander ejected both its heat shield and parachute way ahead of schedule. Schiaparelli then engaged its thrusters for a painfully brief three-second burst—a procedure that was supposed to last for 30 seconds once the lander was just a few feet off the ground. The lander’s onboard computer, it would appear, seems to have thought it was close to the surface. Indeed, Schiaparelli even took the time to switch on some of its instruments, including tools to record the planet’s weather and electrical field.
The sad reality is that Schiaparelli was still somewhere between 1.25 to 2.5 miles above the surface when this happened, falling at a rate of about 185 mph (300 km/h). It struck the ground with tremendous force, resulting in an explosion—and a brand new surface feature."