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Mars landers must be built to survive a long trip from Earth, then a high-speed, ultra-hot journey through Mars’ carbon dioxide-rich atmosphere.
They require protection against a heat of several thousand degrees Celsius (Fahrenheit), generated by atmospheric friction upon atmospheric entry, extreme braking, and a soft touchdown in terrain where any jagged rocks or craters could spell doom.
Schiaparelli should reach the atmosphere at an altitude of 121km and a speed of nearly 21,000 kilometres per hour.
The extreme ride through Mars’ atmosphere will take six minutes. A discardable “aeroshell” will protect the lander against heat generated by atmospheric drag, while a supersonic parachute and nine thrusters will brake it.
A crushable structure in the lander’s belly is meant to cushion the final impact.
With a 10-minute delay — the time it takes for a message to reach Earth — Schiaparelli will send data on temperature, humidity, density profile and electrical properties — information seen as crucial to plan a safe landing for the much bigger and more expensive rover to follow.
Battery-driven and without solar panels, the lander should last for two or three days.
Having released its precious charge, the TGO will be commanded overnight Sunday to change course to avoid joining Schiaparelli on the surface, instead entering an elongated and erratic orbit Mars orbit.
It will then start a 12-month process of “aerobraking” — skimming the Martian atmosphere to bleed off energy — to change its orbit into a more regular, circular one.
Once this is achieved, in early 2018, it will begin its work of analysing the Mars atmosphere from about 400km for methane.