European Space Agency's Mars lander may have exploded on impact with the red planet, scientists suggest after preliminary analysis of new images taken by a NASA probe.
ESA's ExoMars Schiaparelli entered the Martian atmosphere on October 19 for its 6-minute descent to the surface, but contact was lost shortly before expected touchdown.
Data recorded by its mothership, the Trace Gas Orbiter, are being analysed to understand what happened during the descent sequence, ESA said.
NASA's Mars Reconnaissance Orbiter identified new markings on the surface of the Red Planet that are believed to be related to Schiaparelli entry, descent and landing technology demonstrator module.
The low-resolution CTX camera on-board the MRO took pictures of the expected touchdown site in Meridiani Planum on October 20 as part of a planned imaging campaign.
The image released has a resolution of 6 metres per pixel and shows two new features on the surface when compared to an image from the same camera taken in May this year.
One of the features is bright and can be associated with the 12 metre diameter parachute used in the second stage of Schiaparelli's descent, after the initial heat shield entry.
The parachute and the associated back shield were released from Schiaparelli prior to the final phase, during which its nine thrusters should have slowed it to a standstill just above the surface.
The other new feature is a fuzzy dark patch roughly 15x40 metres in size and about 1 km north of the parachute.
This is interpreted as arising from the impact of the Schiaparelli module itself following a much longer free fall than planned, after the thrusters were switched off prematurely.
Estimates are that Schiaparelli dropped from a height of between two and four kilometres, therefore impacting at a considerable speed, greater than 300 km/h.
The relatively large size of the feature would then arise from disturbed surface material.
It is also possible that the lander exploded on impact, as its thruster propellant tanks were likely still full. These preliminary interpretations will be refined following further analysis.
A closer look at these features will be taken next week with HiRISE, the highest-resolution camera onboard MRO. These images may also unveil the location of the front heat shield, dropped at higher altitude.
Since the module's descent trajectory was observed from three different locations, the teams are confident that they will be able to reconstruct the chain of events with great accuracy. The exact mode of anomaly onboard Schiaparelli is still under investigation.
The ExoMars TGO orbiter is currently on a 101,000 km x 3,691 km orbit (with respect to the centre of the planet) with a period of 4.2 days, well within the planned initial orbit.
IMAGE: An illustration released by the European Space Agency shows the Schiaparelli EDM lander.