New Clues on Fate of Schiaparelli Mars Lander

The European Space Agency has released its investigation into the crash of the Schiaparelli Mars lander in October 2016.

Perhaps the loss of one mission will benefit another. A recent independent external inquiry, chaired by the European Space Agency's Inspector General, has shed new light on the fate of ESA's Schiaparelli Lander. A test bed for the full up ExoMars 2020 rover, the lander slammed into the Meridiani Planum landing site at 540 kilometers per hour (340 mph) on October 19, 2016.

Schiaparelli's Journey

Named after the 19th century Italian astronomer who mapped the Red Planet, Schiaparelli came heartbreakingly close to a successful landing. Schiaparelli hitched a ride to Mars attached to the ExoMars Trace Gas Orbiter. Both spacecraft launched atop a Roscosmos Proton rocket from the Baikonur Cosmodrome in Kazakhstan, Russia, on March 14, 2016. The plan was for the Schiaparelli Entry, Descent and Landing (EDM) demonstrator to measure atmospheric conditions during and after landing. Schiaparelli was battery-powered (though early plans had called for a nuclear-fueled RTG power supply, like Curiosity) and was set to operate for a few days on the Martian surface.

The Schiaparelli mission featured several attempted firsts: the first time a lander relayed data to its parent ship (TGO) while it was also entering orbit, the first time science data related to dust storm development was collected during descent, and the first lander to feature a deformable underside similar to crumble zones on an automobile to cushion the impact of landing.

Anatomy of an Interplanetary Crash

At first, all went according to plan. Schiaparelli was released from the TGO on October 16, 2016, three days ahead of the scheduled landing. Then, on October 19th, Schiaparelli began its own “six-minutes of terror” as planned: the heat shield protected the spacecraft during initial atmospheric interface, sensors took atmospheric readings, and the parachute deployed on schedule.

ESA's Mars Express caught Schiaparelli's carrier signal during descent, as did the Giant Metrewave Radio Telescope based in Pune, India.

Problems started about three minutes into atmospheric entry, when Schiaparelli began to spin under its chute. This spin began with parachute inflation, resulting — in the words of the investigation findings — in a “saturation,” exceeding the measurement range of the lander's Inertial Measurement Unit or IMU. This conflict made the lander think it was below ground level, when it was, in fact, still 3.7 kilometers above the Martian surface. The terminal descent phase kicked in, and the lander ejected its backshell and parachute ahead of schedule. To make matters worse, the landing thrusters only fired for 3 seconds, instead of 30 seconds, before falling silent. This put Schiaparelli in a 25-second free fall before slamming into the Martian surface, creating a fresh new Martian crater spied by the Mars Reconnaissance Orbiter weeks later on November 1, 2016.

The surface science package, thinking the spacecraft had already landed, relayed one “housekeeping packet” of data during descent before losing contact.

The investigating team noted that the lander impacted very near the anticipated landing site, revealing that the chute and reentry went off very nearly as planned.

The “saturation” of the IMU parameters allowed the team to identify weak spots and possible software fixes, findings that will go a long way towards getting the Mars 2020 rover safely down to the Martian surface.

“The real-time relay of data during the descent was crucial to provide this in-depth analysis of Schiaparelli's fate,” said David Parker (ESA-Human Spaceflight and Robotic Exploration) in a recent press release. “We will take the lessons learned with us as we continue to prepare for the ExoMars 2020 rover and surface platform mission. Landing on Mars is an unforgiving challenge but one we must meet to achieve our ultimate goals.”

Schiaparelli: Paying it Forward

Currently, ESA's Mars Trace Gas Orbiter is working well, and will aerobrake during Mars periapsis for a series of science orbits in 2018. The ExoMars 2020 rover is also on track for a July 2020 launch.

Space is hard, and if there's one thing the “Great Galactic Ghoul” loves, it's tasty human spacecraft bound for Mars. But the lessons learned from the ESA Schiaparelli EDM landing attempt will be paid forward towards the crucial landing of the ExoMars rover.