Views Of Mars Show Potential For ESA’s New Orbiter

Image of a 1.4 km sized crater (left centre) on the rim of a much larger crater near the Mars equator. It was acquired at 7.2 metres/pixel. The images are very sharp and show the instrument is working extremely well at its nominal data acquisition rates. Image Credit: ESA/Roscosmos/ExoMars/CaSSIS/UniBE

Image of a 1.4 km sized crater (left centre) on the rim of a much larger crater near the Mars equator. It was acquired at 7.2 metres/pixel. The images are very sharp and show the instrument is working extremely well at its nominal data acquisition rates. Image Credit: ESA/Roscosmos/ExoMars/CaSSIS/UniBE

November 29, 2016 – The European Space Agency’s (ESA’s) new ExoMars orbiter has tested its suite of instruments in orbit for the first time, hinting at a great potential for future observations.

The Trace Gas Orbiter, or TGO, a joint endeavour between ESA and Roscosmos, arrived at Mars on October 19. Its elliptical orbit takes it from 230–310 km above the surface to around 98 000 km every 4.2 days.

It spent the last two orbits during November 20-28 testing its four science instruments for the first time since arrival, and making important calibration measurements.

Data from the first orbit has been made available for this release to illustrate the range of observations to be expected once the craft arrives into its near-circular 400 km-altitude orbit late next year.

TGO’s main goal is to make a detailed inventory of rare gases that make up less than 1% of the atmosphere’s volume, including methane, water vapour, nitrogen dioxide and acetylene.

Of high interest is methane, which on Earth is produced primarily by biological activity, and to a smaller extent by geological processes such as some hydrothermal reactions.

The two instruments tasked with this role have now demonstrated they can take highly sensitive spectra of the atmosphere. During the test observations last week, the Atmospheric Chemistry Suite focused on carbon dioxide, which makes up a large volume of the planet’s atmosphere, while the Nadir and Occultation for Mars Discovery instrument homed in on water.They also coordinated observations with ESA’s Mars Express and NASA’s Mars Reconnaissance Orbiter, as they will in the future.

The ExoMars Trace Gas Orbiter’s Atmospheric Chemistry Suite made test measurements of the martian atmosphere on 22 November 2016 at thermal-infrared wavelengths. Such measurements will provide information on dust and ice particles, temperature profiles and concentration of gases. The inset zooms in to part of the graph with a carbon dioxide feature characteristic of the atmospheric structure, which will be useful in probing the thermal structure of the atmosphere. Image Credit:  ESA/Roscosmos/ExoMars/ACS/IKI

The ExoMars Trace Gas Orbiter’s Atmospheric Chemistry Suite made test measurements of the martian atmosphere on 22 November 2016 at thermal-infrared wavelengths. Such measurements will provide information on dust and ice particles, temperature profiles and concentration of gases. The inset zooms in to part of the graph with a carbon dioxide feature characteristic of the atmospheric structure, which will be useful in probing the thermal structure of the atmosphere. Image Credit: ESA/Roscosmos/ExoMars/ACS/IKI

Complementary measurements by the orbiter’s neutron detector, FREND, will measure the flow of neutrons from the planet’s surface. Created by the impact of cosmic rays, the way in which they are emitted and their speed on arriving at TGO points to the composition of the surface layer, in particular to water or ice just below the surface.

Example of data collected by the ExoMars Trace Gas Orbiter’s Fine Resolution Epithermal Neutron Detector (FREND), showing the flux of fast neutrons measured by the instrument. The graph shows an average of all the measurements around the closest approach to the planet along six recent orbits. The result shows a simple demonstration that there is a clear increase in count rate when close to Mars compared to farther away. Image Credit: ESA/Roscosmos/ExoMars/FREND/IKI

Example of data collected by the ExoMars Trace Gas Orbiter’s Fine Resolution Epithermal Neutron Detector (FREND), showing the flux of fast neutrons measured by the instrument. The graph shows an average of all the measurements around the closest approach to the planet along six recent orbits. The result shows a simple demonstration that there is a clear increase in count rate when close to Mars compared to farther away. Image Credit: ESA/Roscosmos/ExoMars/FREND/IKI

The instrument has been active at various times during the cruise to Mars and on recent occasions while flying close to the surface could identify the relative difference between regions of known higher and lower neutron flux, although it will take several months to produce statistically significant results.

Similarly, the instrument showed a clear increase in neutron detections when close to Mars compared to when it was further away.

The different capabilities of the Colour and Stereo Surface Imaging System were also demonstrated, with 11 images captured during the first close flyby on 22 November.

The first stereo reconstruction of a small area in Noctis Labyrinthus. The image gives an altitude map of the region with a resolution of less than 20 metros. Image Credit: ESA/Roscosmos/ExoMars/CaSSIS/UniBE

The first stereo reconstruction of a small area in Noctis Labyrinthus. The image gives an altitude map of the region with a resolution of less than 20 metros. Image Credit: ESA/Roscosmos/ExoMars/CaSSIS/UniBE

At closest approach the spacecraft was 235 km from the surface, and flying over the Hebes Chasma region, just north of the Valles Marineris canyon system. These are some of the closest images that will ever be taken of the planet by TGO, given that the spacecraft’s final orbit will be at around 400 km altitude.

A structure called Arsia Chasmata on the flanks of one of the large volcanoes, Arsia Mons. The width of the image is around 25 km. The formation is volcanic in origin and pit craters (possibly caused by subsidence) can be seen. Image Credit: ESA/Roscosmos/ExoMars/CaSSIS/UniBE

A structure called Arsia Chasmata on the flanks of one of the large volcanoes, Arsia Mons. The width of the image is around 25 km. The formation is volcanic in origin and pit craters (possibly caused by subsidence) can be seen. Image Credit: ESA/Roscosmos/ExoMars/CaSSIS/UniBE

Although the images are impressively sharp, data collected during this test period will help to improve the camera’s onboard software as well as the quality of the images after processing.

“We are extremely happy and proud to see that all the instruments are working so well in the Mars environment, and this first impression gives a fantastic preview of what’s to come when we start collecting data for real at the end of next year,” says Håkan Svedhem, ESA’s TGO Project Scientist.

“Not only is the spacecraft itself clearly performing well, but I am delighted to see the various teams working together so effectively in order to give us this impressive insight.

“We have identified areas that can be fine-tuned well in advance of the main science mission, and we look forward to seeing what this amazing science orbiter will do in the future.”