Schiaparelli EDM lander

Schiaparelli EDM lander. The Schiaparelli Entry, Descent and Landing Demonstrator Module was a component of the ExoMars program, a joint astrobiology project between the European Space Agency and Roscosmos. Its primary role was to validate key technologies for a controlled landing on the surface of Mars, paving the way for the subsequent Rosalind Franklin rover mission. Although the module successfully entered the Martian atmosphere and deployed its parachute, a fatal error during the final descent phase led to a catastrophic crash in the Meridiani Planum region.

Introduction

The Schiaparelli module was conceived as a critical engineering precursor within the ambitious ExoMars program, which itself emerged from earlier collaborative studies between ESA and NASA. Named for the Italian astronomer Giovanni Schiaparelli, renowned for his observations of canali on Mars, the lander was designed to build upon the legacy of Europe's first attempt at Martian surface operations with the Beagle 2. Launched together with the ExoMars Trace Gas Orbiter aboard a Proton-M rocket from the Baikonur Cosmodrome, its journey was part of a broader international effort to understand the Red Planet, joining contemporary missions like the Mars Science Laboratory.

Design and Development

The spacecraft's design was led by the prime contractor Thales Alenia Space in Italy, with significant contributions from Lavochkin in Russia and numerous subcontractors across ESA member states. Its structure consisted of a front shield, a back cover, and a descent module, engineered to withstand the extreme heat of atmospheric entry. Key systems included a Doppler radar altimeter for final descent measurements, a suite of guidance sensors, and a crushable structure for impact absorption. The development faced challenges integrating systems from the different partners, particularly the complex entry, descent, and landing sequence, which was a primary focus of testing at facilities like the European Space Research and Technology Centre.

Mission Objectives

The core objective was purely technological: to demonstrate Europe's capability to perform a controlled soft landing on Mars, a feat previously achieved only by NASA and the Soviet space program. Specific goals included testing the performance of the aeroshell and thermal protection during hypersonic entry, validating the parachute deployment system in the thin Martian atmosphere, and proving the operation of the liquid-propellant retrorocket system during terminal descent. A secondary objective involved operating a small, non-rechargeable battery-powered science package called DREAMS for a few days to measure local atmospheric conditions at the landing site.

Landing and Crash

On 19 October 2016, Schiaparelli separated from the ExoMars Trace Gas Orbiter and initiated its entry into the atmosphere over Meridiani Planum. Initial phases, including atmospheric deceleration and parachute deployment, proceeded nominally. However, a critical anomaly occurred when the Inertial Measurement Unit saturated, causing the onboard computer to erroneously believe it was below ground level while still approximately 3.7 km high. This led to the premature jettisoning of the parachute and backshell and a brief, 1-second firing of the retrorockets before they were commanded off, resulting in the module free-falling and impacting the surface at an estimated speed of over 300 km/h.

Investigation and Legacy

An independent inquiry board appointed by ESA traced the root cause to a design flaw in the entry, descent, and landing software, where the IMU saturation created a "negative altitude" estimation. The board's recommendations led to major revisions in the design, verification, and management processes for the subsequent ExoMars rover mission. Despite the crash, the mission was deemed a "partial success" because the telemetry captured during descent provided invaluable engineering data on the performance of most landing systems. The event underscored the difficulty of Martian landings and significantly influenced the development philosophy for future ESA planetary missions.

Technical Specifications

The lander had a total launch mass of 577 kg, with a 299 kg descent module protected by a 2.4-meter diameter aeroshell. Power was supplied by a non-rechargeable battery with a capacity of 1350 Wh. Its scientific payload, the DREAMS suite, included sensors to measure atmospheric pressure, temperature, humidity, wind speed, atmospheric opacity, and surface electric fields. The landing system comprised a 12-meter diameter disc-gap-band parachute, three clusters of hydrazine monopropellant retro-rockets, and a final crushable aluminum honeycomb structure designed to absorb the impact energy.