A joint European and Russian space mission put a spacecraft into orbit around Mars on Wednesday afternoon. But scientists think the second part of the mission, landing a module on the surface of the planet, did not go as planned.
The ExoMars 2016 mission, made up of the Trace Gas Orbiter (TGO) spacecraft and Schiaparelli lander, set off from Earth in March this year, and reached the vicinity of Mars a few days earlier.
ESA announced on Wednesday that TGO successfully made it into orbit. Now it's there, TGO will look for traces of certain gasses in the Martian atmosphere.
The Schiaparelli lander, named after 19th-century astronomer Giovanni Schiaparelli, who described surface features on Mars, was designed to act as a test for new technology that might be used in future Mars missions. But its fate is still up in the air.
Schiaparelli separated from TGO on Sunday, and since then had been "asleep" and floating towards Mars. ESA received confirmation that the lander has woken up on schedule, and if all went to plan, the lander should have entered the atmosphere of the planet at 3:42pm UK time, and touched down six minutes later.
Schiaparelli was programmed to take 15 pictures as it descended to the surface of Mars.
ESA says it has received data from most of the lander's descent through the Martian atmosphere, but is missing the crucial last minute that would tell them whether the touchdown itself went as planned.
There are a few ways the ESA team planned to monitor the lander's descent. Technology was installed in the Giant Metrewave Radio Telescope (GMRT) in India in the hope that it would be able to detect a signal from the lander in real time.
And the GMRT did pick up a signal showing the lander was awake at the scheduled time, and that it began its descent. But that signal was lost 50 seconds before the final landing.
ESA's Mars Express spacecraft also tracked the landing from orbit – just as it did when NASA's Curiosity rover landed on the planet. Scientists analysed the Mars Express data when it arrived on Wednesday, but said it was "inconclusive".
The scientists then worked through the night on Wednesday to try to piece together all the data they had – from Schiaparelli itself, the GMRT telescope in India, and Mars Express – to work out what happened to the lander.
But data that should have come from NASA's Mars Reconnaissance Orbiter during a planned flyover of Schiaparelli's landing site on Wednesday did not come through.
In a press briefing broadcast on Thursday morning from the ESA operations centre in Darmstadt, Germany, spacecraft operations manager Andrea Accomazzo said data from the lander itself shows that "everything worked as planned up to a certain point".
Data shows that Schiaparelli's parachute and heat shield both deployed, although possibly earlier than they should have. But it's looking increasingly likely that the lander's thrusters fired for only three to four seconds, instead of the planned 30 seconds. If that did happen, Schiaparelli would have got a much harder landing than expected.
“In terms of the Schiaparelli test module, we have data coming back that allow us to fully understand the steps that did occur, and why the soft landing did not occur,” said David Parker, ESA’s director of human spaceflight and robotic exploration.
“From the engineering standpoint, it’s what we want from a test, and we have extremely valuable data to work with. We will have an enquiry board to dig deeper into the data and we cannot speculate further at this time.”
When asked for his "gut feeling" on whether we'd ever know what happened to the lander, Accomazzo said: "I'm convinced that we will understand what has gone on through descent and we will be able to explain what we have seen. I have no doubts."
On Friday Accomazzo's prediction seemed to come true when ESA released images taken by the Mars Reconnaissance Orbiter of the site where the Schiaparelli lander should have touched down. They show two new features on the surface that weren't there when the spacecraft last imaged the site in May.
ESA reckons one of the features is the lander's parachute. They believe the other, a "fuzzy dark patch" about 15 by 40 metres in size that can be seen 1km north of the parachute, was created by the lander itself as it crashed into the planet.
Current best estimates suggest that Schiaparelli dropped from between 2 and 4km above the surface of the planet, and would have hit the ground while it was going at over 300km/h. The impact would have disturbed the surrounding material.
Kelly Oakes is science editor for BuzzFeed and is based in London.
Contact Kelly Oakes at firstname.lastname@example.org.
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