ExoMars: orbiter in good shape, fate of lander unknown
ExoMars: orbiter in good shape, fate of lander unknown

| Staff writer 404 mots

ExoMars: orbiter in good shape, fate of lander unknown

The European Space Agency (ESA) is reporting at least a partial success for the 2016 leg of its ExoMars programme — a joint Mars exploration endeavour between ESA and Russian space agency Roscosmos.

ExoMars 2016 comprises the Schiaparelli entry, descent and landing demonstrator module (EDM) and the Trace Gas Orbiter (TGO), designed to search for evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes.

Following the planned separation of the two craft, on 16th October, the Trace Gas Orbiter (TGO) of has successfully performed the 139-minute burn required to be captured by Mars and entered an elliptical orbit around the Red Planet. TGO becomes Europe’s second orbiter around Mars, joining the 13-year-old Mars Express.

However, teams at the European Space Operations Centre (ESOC) in Darmstadt, Germany, are still trying to make contact with the Schiaparelli lander, which entered the Martian atmosphere some 107 minutes after TGO started its own orbit insertion manoeuvre.

Schiaparelli was programmed to autonomously perform an automated landing sequence, with parachute deployment and front heat shield release between 11 and 7km, followed by a retrorocket braking starting at 1,100m from the ground, and a final fall from a height of 2 m protected by a crushable structure.

Prior to atmospheric entry at 14:42 UTC, contact via the Giant Metrewave Radio Telescope (GMRT), the world's largest interferometric array, located near Pune, India, was established just after it began transmitting a beacon signal 75 minutes before reaching the upper layers of the Martian atmosphere. However, the signal was lost some time prior to landing.

Data confirm that the entry and descent stages occurred as expected, ESA reports, with events diverging from what was expected after the ejection of the back heat shield and parachute. This ejection itself appears to have occurred earlier than expected. The thrusters were confirmed to have been briefly activated although it seems likely that they switched off sooner than expected, at an altitude that is still to be determined.

A series of windows have been programmed to listen for signals coming from the lander via ESA'S Mars Express and NASA's Mars Reconnaissance Orbiter (MRO) and Mars Atmosphere & Volatile Evolution (MAVEN) probes. The Giant Metrewave Radio Telescope (GMRT) also has listening slots.

If Schiaparelli reached the surface safely, its batteries should be able to support operations for three to ten days, offering multiple opportunities to re-establish a communication link.


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