The Schiaparelli Mission

The Little Lander That Didn't

Schiaparelli lander (cartoon)
This is how the Schiaparelli EDM lander would have looked as it descended to Mars on October 19, 2016. Unfortunately, it crashed and was destroyed. ESA/

October 19, 2016, was supposed to be an exciting Mars landing for the European Space Agency's ExoMars mission science team. They had worked for years to put together an orbiting spacecraft and an entry, descent, and landing demonstrator module (EDM) probe and launched it to the Red Planet in March of the same year. The EDM touchdown was a technology demonstrator that was supposed to show off new technology for future missions while at the same time taking data and sending back images of the Martian surface at a large, flat plain called Meridiani Planum.

The lander was named Schiaparelli, after the famed Italian scientist Giovanni Schiaparelli who studied Mars in the late 1800s. He is most famous for his description of surface features on the planet which he called "canale," meaning "lines." That was mistranslated as "canals" which led such observers as Percival Lowell to assume they were built by intelligent beings. Since that time, people often dreamed of Martians, but more recent explorations show Mars to be a dry, dusty, and apparently lifeless, place.

The lander was laden with instruments and set up to do a robotically controlled descent to the surface. Unfortunately, due to a rash of last-second problems, it crashed to the surface, bringing that part of the mission to a halt. The ExoMars Trace Gas Orbiter worked perfectly and began its study of the Martian atmosphere in 2017.

What Happened to Schiaparelli?

The crash landing of the EDM probe was a devastating loss to the ExoMars team. There was no indication anything was wrong during the eight-month flight to Mars or at approach. The mission was launched from Baikonur Cosmodrome by a Russian Proton-M rocket in March 2016. The two spacecraft arrived at their target in October, separated into orbiter and lander, and the teams prepared for the landing. Every precaution was taken to protect Schiaparelli on the way to the surface. It had a heat shield to keep the heat of atmospheric entry at bay. At the right moment, a parachute was supposed to pop out to slow the craft down from its high-speed atmospheric entry, and retro-rockets (small rockets) were programmed to bring the probe gently down to its final landing site.

All went well as the probe entered the atmosphere at a speed of 21,000 kilometers per hour. The parachute deployed about 11 kilometers above the surface, and Schiaparelli ejected its heat shields once it got low enough to do so. The parachuted was cut loose and the retro-rockets took over when the spacecraft was a kilometer up. Then, they shut down and the spacecraft should have landed safely.

The first indication that the process wasn't going well was about 50 seconds before touchdown. Controllers lost contact with Schiaparelli and it was gone. A huge investigation began, with team members trying to figure out what had gone wrong. Apparently, several problems cropped up with the parachute, onboard guidance systems, and a too-short retro-rocket firing. They all combined to cause the lander to crash at a speed of 540 kilometers per hour, rather than the gentle 10 km/hr that was planned.

ESA Declares a Success

Despite the catastrophic crash that destroyed Schiaparelli, the ExoMars declared the mission a success. This was in part due to the fact that ExoMars orbiter successfully entered Mars orbit and began its observations. In addition, although Schiaparelli didn't survive to do its science work, it did successfully transmit data during its descent, providing a good testbed for new technology ESA hopes to use on future missions. In particular, the ExoMars 2020 mission will be based on technology tested on the ExoMars platforms.

What Was Schiaparelli Carrying?

The hardware to be tested aboard the Schiaparelli lander consisted of a parachute system, thrusters for the retro-rockets, and a radar altimeter. There was also a descent camera, a set of instruments called Dust Characterization, Risk Assessment, and Environmental Analyser on the Martian Surface (DREAMS) package, and other sensors to study the atmosphere on the way down. Once on the surface, the lander was supposed to study its surroundings for about a week to get information about the environment. Some team members were going to study electrification of the atmosphere (if it exists), while others would do extensive topological surveys.

Beyond Schiaparelli

The science that didn't get done due to the Schiaparelli mishap would have been extremely helpful for other, later spacecraft, such as ExoMars 2020, and beyond. All is not lost since the descent information did provide insight into the conditions future spacecraft will face as they settle to the surface. Pieces of the lander can be seen on the Martian surface, and even though it's broken apart, a study of how well the pieces survived the crash also give team members insight into what their next challenges will be when they send another spacecraft to the Red Planet. It's not the first mission to Mars to have problems, but the team hopes it can move forward from this experience.