ExoMars (rover)

The ExoMars rover is a planned robotic Mars rover, part of the international ExoMars programme led by the European Space Agency and the Russian Roscosmos State Corporation.

The plan calls for a Russian launch vehicle, an ESA carrier module and a Russian lander that will deploy the rover to Mars' surface, scheduled to launch in July 2020. Once safely landed, the solar powered rover would begin a seven-month (218-sol) mission to search for the existence of past life on Mars. The ExoMars Trace Gas Orbiter, launched in 2016, will operate as the rover's data-relay satellite.

History
The rover is an autonomous six-wheeled terrain vehicle once designed to weigh up to 295 kg, approximately 60% more than NASA's 2004 Mars Exploration Rovers Spirit and Opportunity, but about one third that of NASA's Curiosity rover launched in 2011.

In February 2012, following NASA's withdrawal, the ESA went back to previous designs for a smaller rover, once calculated to be 207 kg. Instrumentation will consist of the exobiology laboratory suite, known as "Pasteur analytical laboratory" to look for signs of biomolecules or biosignatures from past life. Among other instruments, the rover will also carry a 2 m sub-surface drill to pull up samples for its on-board laboratory.

The lead builder of the ExoMars rover, the British division of Airbus Defence and Space, began procuring critical components in March 2014. In December 2014, ESA member states approved the funding for the rover, to be sent on the second launch in 2018, but insufficient funds had already started to threaten a launch delay until 2020. The wheels and suspension system are paid by the Canadian Space Agency and are being manufactured by MDA Corporation in Canada.

By March 2013, the spacecraft was scheduled to launch in 2018 with a Mars landing in early 2019. However, delays in European and Russian industrial activities and deliveries of scientific payloads, forced the launch to be pushed back. In May 2016, ESA announced that the mission had been moved to the next available launch window of July 2020. An ESA ministerial meeting in December 2016 will consider mission issues including €300 million in ExoMars funding and lessons learned from the ExoMars 2016 Schiaparelli mission. One concern is that the Schiaparelli module crashed during its Mars atmospheric entry, and this landing system is being produced in near duplication for the ExoMars lander.

In July 2018, the European Space Agency launched a public outreach campaign to choose a name for the rover.

Navigation
The ExoMars mission requires the rover to be capable of driving 70 m across the Martian terrain per sol to enable it to meet its science objectives. The rover is designed to operate at least seven months and drive 4 km, after landing.

Since the rover communicates with the ground controllers via the ExoMars Trace Gas Orbiter, and the orbiter only passes over the rover approximately twice per sol, the ground controllers will not be able to actively guide the rover across the surface. The ExoMars Rover is therefore designed to navigate autonomously across the Martian surface. A pair of stereo cameras allow the rover to build up a 3D map of the terrain, which the navigation software then uses to assess the terrain around the rover so that it avoids obstacles and finds an efficient route to the ground controller specified destination.

On 27 March 2014, a "Mars Yard" was opened at Airbus Defence and Space in Stevenage, UK, to facilitate the development and testing of the rover's autonomous navigation system. The yard is 30 by and contains 300 t of sand and rocks designed to mimic the terrain of the Martian environment.

Payload
The rover will search for two types of subsurface life signatures, morphological and chemical. It will not analyse atmospheric samples, and it has no dedicated meteorological station, but the ExoMars 2020 surface platform that will deploy the rover is equipped with a meteorological station. The 26 kg scientific payload is as follows:

Panoramic Camera System (PanCam)
The PanCam has been designed to perform digital terrain mapping for the rover and to search for morphological signatures of past biological activity preserved on the texture of surface rocks. The PanCam assembly includes two wide angle cameras for multi-spectral stereoscopic panoramic imaging, and a high resolution camera for high-resolution colour imaging. The PanCam will also support the scientific measurements of other instruments by taking high-resolution images of locations that are difficult to access, such as craters or rock walls, and by supporting the selection of the best sites to carry out exobiology studies. Stained glass calibration targets will provide a UV-stable reflectance and colour reference for the PanCam, ISEM and CLUPI instruments, allowing for the generation of calibrated data products.

Core drill
The present environment on Mars is exceedingly hostile for the widespread proliferation of surface life: it is too cold and dry and receives large doses of solar UV radiation as well as cosmic radiation. Notwithstanding these hazards, basic microorganisms or their ancient remains may be found in protected places underground or within rock cracks and inclusions. Sampling from beneath the Martian surface with the intent to reach and analyze material unaltered or minimally affected by cosmic radiation is the strongest advantage of the ExoMars rover. The ExoMars core drill was fabricated in Italy and is called DEEDRI. It is designed to acquire soil samples down to a maximum depth of 2 m in a variety of soil types. The drill will acquire a core sample 1 cm in diameter by 3 cm in length, extract it and deliver it to the inlet port of the Rover Payload Module, where the sample will be distributed, processed and analyzed. The ExoMars drill embeds the Mars Multispectral Imager for Subsurface Studies (Ma-Miss) which is a miniaturised infrared spectrometer devoted to the borehole exploration. The system will complete experiment cycles and at least two vertical surveys down to 2 metres (with four sample acquisitions each). This means that a minimum number of 17 samples shall be acquired and delivered by the drill for subsequent analysis. The drill mechanism transfers the sample to the sample container that presents the material to three analytic instruments: MicrOmega-IR, MOMA and Raman Laser Spectrometer.

Pasteur instrument suite
The science package in the ExoMars rover will hold a variety of instruments collectively called Pasteur suite; these instruments will study the environment for habitability, and possible past biosignatures on Mars. These instruments are placed internally and used to study collected samples:


 * Mars Organic Molecule Analyzer (MOMA) is the rover's largest instrument. It will conduct a broad-range, very-high sensitivity search for organic molecules in the collected sample. It includes two different ways for extracting organics: laser desorption and thermal volatilisation, followed by separation using four GC-MS columns. The identification of the evolved organic molecules is performed with an ion trap mass spectrometer. The Max Planck Institute for Solar System Research is leading the development. International partners include NASA. The mass spectrometer is provided from the Goddard Space Flight Center, while the GC is provided by the two French institutes LISA and LATMOS. The UV-Laser is being developed by the Laser Zentrum Hannover.
 * MicrOmega-IR is an infrared hyperspectral microscope that can analyse the powder material derived from crushing samples collected by the core drill. Its objective is to study mineral grain assemblages in detail to try to unravel their geological origin, structure, and composition. These data will be vital for interpreting past and present geological processes and environments on Mars. Because MicrOmega-IR is an imaging instrument, it can also be used to identify grains that are particularly interesting, and assign them as targets for Raman and MOMA-LDMS observations.
 * Raman Laser Spectrometer (RLS) is a Raman spectrometer that will provide geological and mineralogical context information complementary to that obtained by MicrOmega-IR. It is a very fast and useful technique employed to identify mineral phases produced by water-related processes.  It will help to identify organic compounds and search for life by identifying the mineral products and indicators of biologic activities (biosignatures).

External

 * WISDOM (Water Ice and Subsurface Deposit Information On Mars) is a ground-penetrating radar that will explore the subsurface of Mars to identify layering and help select interesting buried formations from which to collect samples for analysis. It can transmit and receive signals using two, small Vivaldi-antennas mounted on the aft section of the rover. Electromagnetic waves penetrating into the ground are reflected at places where there is a sudden transition in the electrical parameters of the soil. By studying these reflections it is possible to construct a stratigraphic map of the subsurface and identify underground targets down to 2 to 3 m in depth, comparable to the 2 m reach of the rover's drill. These data, combined with those produced by the PanCam and by the analyses carried out on previously collected samples, will be used to support drilling activities.
 * Mars Multispectral Imager for Subsurface Studies (Ma-MISS) is an infrared spectrometer located inside the core drill. Ma-MISS will observe the lateral wall of the borehole created by the drill to study the subsurface startigraphy, to understand the distribution and state of water-related minerals, and to characterise the geophysical environment. The analyses of unexposed material by Ma-MISS, together with data obtained with the spectrometers located inside the rover, will be crucial for the unambiguous interpretation of the original conditions of Martian rock formation. The composition of the regolith and crustal rocks provides important information about the geologic evolution of the near-surface crust, the evolution of the atmosphere and climate, and the existence of past life.
 * Close-Up Imager (CLUPI), to visually study rock targets at close range (50 cm) with sub-millimetre resolution. This instrument will also investigate the fines produced during drilling operations, and image samples collected by the drill. The close-up imager has variable focusing and can obtain high-resolution images at longer distances.

Russian instruments

 * The Infrared Spectrometer for ExoMars (ISEM), will be installed on the rover's mast. It will be used to assess bulk mineralogy characterization and remote identification of water-related minerals. Working with PanCam, ISEM will contribute to the selection of suitable samples for further analysis by the other instruments.
 * ADRON-RM is a neutron spectrometer to search for subsurface water ice and hydrated minerals. It will be used in combination with WISDOM instrument (a ground-penetrating radar) to study the subsurface beneath the rover and to search for optimal sites for drilling and sample collection.
 * Fourier spectrometer, mounted on the rover's mast will acquire temperature and aerosol measurements.
 * Roscosmos will also provide radioisotope heater units (RHU) for the rover to keep its electronic components warm at night.

Optional scouting micro rover
NASA's Mars rover Spirit got stuck permanently in soft sand in 2009, so European engineers are assessing the option of including a "scout" micro rover to prod the ground 5 meters ahead of this primary rover to improve the mission safety and speed by determining the suitability of the terrain. The scout rover study is called FASTER (Forward Acquisition of Soil and Terrain Data for Exploration Rover), and it is a European consortium of six partners from five EU member states. Both rovers would collaborate autonomously during their mission; FASTER would be equipped with a Soil Sensing System (SSS) to analyse soil and terrain properties for hazardous soft sand traction. The micro rover would dock to the primary rover for energy transfer, or potentially, be stowed on board and be released when required. The estimated dimensions of the scout rover are 40 x 83 x 50 cm (H x L x W) with a mass of 10 to 15 kg.

De-scoped instruments
The proposed payload has changed several times. The last major change was after the program switched from the larger rover concept back to the previous 300 kg rover design in 2012.


 * Mars X-Ray Diffractometer (Mars-XRD) - Powder diffraction of X-rays would give exact composition of the crystalline minerals. This instrument includes also an X-ray fluorescence capability that can provide useful atomic composition information. The identification of concentrations of carbonates, sulphides or other aqueous minerals may be indicative of a Martian [hydrothermal] system capable of preserving traces of life. In other words, it would examine the past Martian environmental conditions, and more specifically the identification of conditions related to life.
 * The Urey instrument was planned to search for organic compounds in Martian rocks and soils as evidence for past life and/or prebiotic chemistry. Starting with a hot water extraction, only soluble compounds are left for further analysis. Sublimation, and capillary electrophoresis makes it possible to identify amino acids. The detection would be by laser-induced fluorescence, a highly sensitive technique, capable of parts-per-trillion sensitivity. These measurements would be made at a thousand times greater sensitivity than the Viking GCMS experiment, and would significantly advance our understanding of the organic chemistry of Martian soils.
 * Miniaturised Mössbauer Spectrometer (MIMOS-II) provides the mineralogical composition of iron-bearing surface rocks, sediments and soils. Their identification would aid in understanding water and climate evolution and search for biomediated iron-sulfides and magnetites, which could provide evidence for former life on Mars.
 * The Life Marker Chip was for some time part of the planned payload. This instrument was intended to use a surfactant solution to extract organic matter from samples of martian rock and soil, then detect the presence of specific organic compounds using an antibody-based assay.

Landing site selection
After a review by an ESA-appointed panel, a short list of four sites was formally recommended in October 2014 for further detailed analysis. These landing sites exhibit evidence of a complex aqueous history in the past.
 * Mawrth Vallis
 * Oxia Planum
 * Hypanis Vallis
 * Aram Dorsum

On 21 October 2015, Oxia Planum was chosen as the preferred landing site for the ExoMars rover, with Aram Dorsum and Mawrth Vallis as backup options.

After the ExoMars 2020 surface platform lands, it will deploy ramps to deliver the ExoMars rover to the surface. The platform will remain stationary and will start a one-year mission to investigate the surface environment at the landing site.