We had already reported about the successful launch of the ExoMars 2016 mission on March 14, 2016. There are two spacecrafts involved in this mission – the Trace Gas Orbiter (TGO) and the Schiaparelli landing demonstrator. Both crafts of this joint ESA/Roscosmos mission will arrive in the vicinity of Mars in October 2016 after a cruise of 7 months. Then it will be the heaviest spacecraft that has ever arrived at Mars. We will keep the fingers crossed!
In this article we will talk about the scientific instruments on-board of both spacecrafts – orbiter and lander. Let us start with the instruments of the orbiter. A the name Trace Gas Orbiter is suggesting the main task of the orbiter is to search for trace gases in the atmosphere of Mars. The gas methane is of special interest here. It is not understood yet why Methane is present in the atmosphere of Mars. On Earth the methane is mainly produced in biological processes (90 percent). 10 percent of the methane on Earth has its origin in geological processes like vulcanic eruptions. But on Mars no processes like these on Earth were observed – yet. With help of the instruments on TGO a map of methane on Mars resolved in space and time will be created. This map should help to understand where on Mars methane is formed, and where it is disappearing again. This is another mystery of the methane on Mars – it disappeares much faster than models predict.
As this mapping of methane on Mars is very important there are two instruments on-board of TGO with the capability to do so: the Russian ACS (Atmospheric Chemistry Suite) and NOMAD (Nadir & Occultation for MArs Discovery !? – Seems to be that it was quite hard to find a name for instrument with the acronym NOMAD – as used in Star Trek TOS ;-)) built in Belgium. NASA had also plans to deliver a similar instrument. These plans were finally not realized. The instruments consist of several spectrometers for different wavelength ranges allowing to detect trace gases when the Sun is shining through the atmosphere of Mars and by looking down vertically to the ground (with less signal/noise). The gained information can be combined with stereo image data collected by another instrument on-board – the Switzerland built CaSSIS (Colour and Stereo Surface Imaging System) to identify the origin of Methane. The identified areas will be examined in a next step. The ExoMars 2018 rover „Bruno“ for instance could drill up to 2 meters deep to search for microbes responsible for the methane!
The fourth instrument of TGO is called FREND (Fine Resolution Epithermal Neutron Detector). It was built in Russia and can detect reservoirs of water ice up to ta few meters deep under the surface of Mars. The resolution of this instrument is 10 times better than instruments already present in Mars orbit. Obviously the mapping of water ice reservoirs is a very important task for future manned missions to Mars.
NASA has also contributed to equip the orbiter. It delivered two „Electra“ UHF communication packages. These will serve as relay stations between surface elements like landers and rovers and ground stations on Earth. The Schiaparelli lander will use this communication link as well as the Curiosity rover of NASA – and future surface elements, too.
The main task of the Schiaparelli lander is the demonstration of landing capabilities for future Mars surface spacecrafts. In early versions of the ExoMars program a „skycrane“ delivered by NASA was supposed to deliver the ExoMars 2018 lander to the surface of Mars. ESA and Roscosmos will build now their own system to deliver the rover to the surface after this NASA contribution was cancelled. Experience collected with Schiaparelli will help to refine this landing system.
For the first time in history with Sciaparelli a lander will go down to the surface of Mars during the sand storm season. The lander will be equipped with instruments to characterize the atmosphere of Mars during these rough conditions.
Schiaparelli will also carry instruments that will work after the touchdown. These instruments will work for a few days only until the battteries of the lander are depleted. The main instrument of the lander is called DREAMS (Dust Characterisation, Risk Assessment, and Environment Analyser on the Martian Surface). This is a weather station mounted on a mast called MetMast. The temperature will be determined by MarsTem. DREAMS-H measures the humidity. The velocity of the wind is determined by MetWind. SIS will monitor the Solar irradiance to determine how much Sun light is blocked by the dust in the atmosphere.
Additional sensors are mounted at the science deck: DREAMS-P will measure the pressure & MicroARES will monitor the electric fields. A laser reflector is also mounted and will allow to locate Schiaparelli by Mars orbiters.
Thus there will be a lot of very interested science conducted after the landing of Schiaparelli – and by the Trace Gas Orbiter from Mars orbit – after their arrival in mid October. I am really looking forward to this! Interesting times – indeed!
Part I of my ExoMars launch coverage:
P.S.: ESA has provided a nice video about the ExoMars 2016 science. Please have a look. Here it is: