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Physical Chemistry

ExoMars orbiter ready to map trace gases

Although Schiaparelli lander crashed, mission’s orbiter will take data around red planet for next four years

by Elizabeth K. Wilson
October 24, 2016

Artist’s rendition of ESA’s Trace Gas Orbiter orbiting Mars.
Credit: ESA/ATG medialab
In this artist’s rendition, the ExoMars 2016 mission’s TGO, carrying the Schiaparelli lander, prepares to orbit Mars.

The missing Mars lander Schiaparelli, meant to touch down on the red planet last week, has been spotted, confirming that its landing did not go as planned. Two days after the craft went silent during its descent, NASA’s Mars Reconnaissance Orbiter sent back images of Mars’s surface highlighting Schiaparelli’s remains at the intended landing site.

ExoMars 2016, a joint mission with the European Space Agency (ESA) and Russia’s Roscosmos, launched Schiaparelli along with another craft, the Trace Gas Orbiter (TGO) in March. The TGO successfully maneuvered into orbit around Mars, and “is now ready for science,” said Johann-Dietrich Woerner, ESA’s director general, at a briefing at ESA’s mission control center in Darmstadt, Germany, last week.

The car-sized lander, however, did not successfully complete its maneuver on Oct. 19. Data transmitted from the craft before impact indicate that the lander’s braking systems malfunctioned, which likely caused it to slam into Mars’s surface at greater than 300 km per hour.

Andrea Accomazzo, head of ESA’s solar system and planetary missions division, confirmed that the lander’s braking rockets did fire, but only for a few seconds, “a time much shorter than we were expecting.”

RIP, Schiaparelli
These before and after images taken by NASA’s Mars Reconnaissance Orbiter show the Schiaparelli lander (black speck) soon after its impact on Mars’s surface.
Credit: NASA/JPL-Caltech/MSSS

Schiaparelli was intended to test technologies that would be used on a rover planned for launch in 2020.

On Oct. 21, NASA released images from its orbiter showing a “before” picture of Mars’s unblemished surface followed by an “after” picture of the surface marred by a black speck.

At the briefing, the ExoMars team did its best to shift focus from the lander’s malfunction to the TGO, which will orbit Mars for four years.

With cameras and spectrometers far more sensitive than ESA’s previous orbiter, Mars Express, the TGO will map trace atmospheric gases such as nitrogen oxides, acetylene, and methane over the seasons. TGO will also be able to detect hydrogen—a signature for water ice—one meter below Mars’s surface.

Scientists are particularly interested in Mars’s production of methane. On Earth, microbes are responsible for producing most atmospheric methane, but the gas can also be produced by geological processes.

NASA’s rover Curiosity detected a spike of methane on Mars two years ago, the source of which remains a mystery. Scientists hope that the TGO might help identify where and when methane is produced on Mars.



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