21.07.2021
ExoMars orbiter continues hunt for key signs of life on Mars
TheESA-Roscosmos Trace Gas Orbiter has set new upper limits on how much methane, ethane, ethylene and phosphine is in the martian atmosphere – four so-called ‘biomarker’ gases that are potential signs of life.
Searching for biomarkers on Mars is a primary goal of the ExoMars Trace Gas Orbiter. A key biomarker of interest is methane, as much of the methane found on Earth is produced by living things or geological activity – and so the same may be true for Mars.
The ‘methane mystery’ on Mars has been ongoing for many years, with contradictory findings from missions including ESA’s Mars Express and NASA’s Curiosity rover capturing sporadic spikes and bursts of the gas in Mars’ atmosphere, fluctuations both in orbit and at the planet's surface, signs of the gas varying with the seasons, or not observing any methane at all.
Previous estimates from Mars and ground-based missions range from 0.2 up to 30 parts per billion by volume (ppbv), indicating up to 30 molecules of methane per billion molecules. For reference, methane is present in Earth’s atmosphere at nearly 2000 ppbv.
However, the first results from the Trace Gas Orbiter, reported in April 2019, spotted no methane, instead calculating that, if present, the gas must have a maximum concentration of just 0.05 ppbv.
“We have now used the Trace Gas Orbiter to refine the upper limit for methane at Mars even further, this time gathering data for over 1.4 martian years – 2.7 Earth years,” says Franck Montmessin of LATMOS, France, Co-Principal Investigator of the Trace Gas Orbiter’s Atmospheric Chemistry Suite (ACS) and lead author of one of a trio of new papers on martian biomarkers.
“We found no sign of the gas at all, suggesting that the amount of methane at Mars is likely even lower than previous estimates suggest.”
As the orbiter’s instruments are highly sensitive, if methane is present it must be at an abundance of less than 0.05 ppbv – and more likely less than 0.02 ppbv, say Franck and colleagues. The scientists also hunted for signs of methane around Curiosity’s home, Gale crater, and found nothing, despite the rover reporting the presence of methane there.
“Curiosity measures right at Mars’ surface while the orbiter takes measurements a few kilometres above – so the difference between these two findings could be explained by any methane being trapped to the lower atmosphere or the immediate vicinity of the rover,” adds Franck.
The apparent lack of martian methane reported by Franck and colleagues is supported by a paper using data from the orbiter’s NOMAD (Nadir Occultation MArs Discovery) instrument, again spanning a full martian year and searching for methane and two other biomarkers.
“We also found no sign of methane on Mars, and set an upper limit of 0.06 ppbv, which agrees with TGO’s initial findings using ACS,” says the paper’s lead author Elise Wright Knutsen, previously at NASA’s Goddard Space Flight Center, USA, and now at LATMOS, France. “As well as searching for global methane, we also looked for localised plumes at over 2000 locations on the planet and didn’t detect anything – so if methane is released in this way, it must be sporadic.”
Alongside methane, Elise and colleagues looked for two other potential biomarker gases: ethane and ethylene. These molecules are expected to occur after methane is broken down by sunlight, and so are exciting both in their own right and in the context of our hunt for methane. Ethane and ethylene molecules also have short lifetimes, meaning that if they are found in a planetary atmosphere they must have been recently released or created via an ongoing process. This makes them excellent tracers of possible biological or geological activity.
“These are ExoMars’ first results hunting for these two gases,” says Elise. “We didn’t detect either, and so set upper limits for ethane and ethylene at 0.1 and 0.7 ppbv, respectively – low, but higher than our limits for methane.”
The orbiter has also been hunting for phosphine – a gas that caused a splash and huge controversy last year when it was allegedly detected at Venus. Most phosphine on Earth is biologically produced, making it an exciting biomarker in the atmospheres of terrestrial planets.
“We didn’t find any signs of phosphine at Mars,” says Kevin Olsen of the University of Oxford, UK, and lead author of the phosphine study. “Our upper limits are similar for those of ethane and ethylene – between 0.1 and 0.6 ppbv.”
The search for life on Mars, or lingering signatures of it, is a central goal of the ExoMars programme, and the hunt for biomarkers in particular is a primary goal of the Trace Gas Orbiter. The forthcoming ExoMars rover Rosalind Franklin, due for launch in 2022, will complement TGO’s hunt for biomarkers by digging down into the martian surface; underground samples may be more likely to retain biomarkers, as material is shielded from the harsh radiation environment of space.
“Whether biomarkers are detected or not, these findings are important for our understanding of which processes occur, and which do not, in the martian atmosphere – essential information when considering where to focus our continued investigation of Mars,” adds Håkan Svedhem, ESA Project Scientist for the ExoMars Trace Gas Orbiter.
“Many key questions remain – for instance, why does Curiosity see methane at Gale Crater, while we find none in orbit? Could this methane have come from elsewhere, or only be found in particular locations across the planet – or could an unexpected process be destroying any methane present before we can detect it?
It will be exciting to continue working collaboratively with missions like the Curiosity and Rosalind Franklinrovers, both of which have totally different vantage points to an orbiter, to really pin down what is happening in this mysterious planetary environment.”
Quelle: ESA
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Update: 4.08.2021
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Science in motion for ExoMars twin rover
The first science tests for the ExoMars rover replica kicked off after several weeks of driving tests around the Mars Terrain Simulator at the ALTEC premises in Turin, Italy.
With the locomotion system up and running, it is time now for the rover’s cameras and instruments to scan a Mars-like terrain – both on and under the surface – in search for the best samples.
The twin of ESA’s Rosalind Franklin rover, also known as The Ground Test Model (GTM), has been busy surveying 64 square metres of terrain in one of Europe’s largest Mars yards, carefully staged with sandy areas and rocks of various sizes, as well as gravity and light simulations to recreate the environment on Mars.
See, snap, survey
Imaging comes first. Two stereo cameras at the top and at the bottom of the rover’s mast – NavCam and LocCam – allow the GTM to ‘see’ in three dimensions and identify the rocks and slopes ahead. The cameras guide the rover through safe paths and help avoid hazards.
Once the rover is on the move, two more sets of cameras – PanCam and CLUPI – come into play to get a whole picture of the site with high resolution imaging. These rover ‘eyes’ send panoramic and close-up images of the terrain to the operators at the Rover Operations Control Centre (ROCC). Teams from Thales Alenia Space and ALTEC worked in synergy with ESA engineers.
The images are essential to map the geological context and to help the scientists decide where the rover should stop and survey the surface in more detail.
Choosing the target
Finding suitable samples involves a lot more than just spotting an outcrop and digging. The rover is equipped with a ground penetrating radar – WISDOM – and a neutron detector – ADRON– to understand what lies beneath the surface.
The search for evidence of life on Mars is a main objective of the ExoMars 2022 mission.
If anywhere on Mars, traces of past or present life are most likely to be found underground, where ancient biological signatures may still be preserved from the harsh radiation on the Red Planet.
Much as archaeologists on Earth excavate sites, WISDOM can work by analysing the area in a grid fashion – by breaking the ground into small squares. The neutron spectrometer in ADRON will work in tandem with the radar to detect water and hydrated minerals below the surface.
Test cases for Mars
Operators are rehearsing all possible mission scenarios to prepare for Rosalind Franklin’s arrival in Oxia Planum on Mars in June 2023.
The first tests with science in action started with the rover doing a traverse to characterise a sandy and flat area. After roving for a while, the cameras fed the operators with stereo and high-resolution images.
Once a location deemed intriguing enough to drill for samples is found, it was time to get more information from beneath the surface.
The ground penetrating radar WISDOM ran its science analysis every 10 cm for 30 seconds. Once the wheeled lab covered five metres, it performed two turns of 90 degrees and started all over again on a new five-metre track. At the end of the test, WISDOM scanned a grid of 25 square metres.
A second test repeated this sequence, this time around with a much longer drive of eight metres for a more far-reaching science acquisition. And instead of stopping every half a metre, the GTM used WISDOM every metre.
In both cases, the sequence was completed by the neutron detector, Adron, which took measurements looking for traces of water. Next up was the execution of a complete WISDOM grid of 25 square metres.
Where to drill?
These dry runs simulate the sequences the rover will follow on Mars, where the scientists will need to decide which area is worth drilling. Rosalind Franklin is fitted with a drill to extract samples down to a maximum of two metres, deeper than any other rover and a first in Mars exploration.
As a bonus during this first science dry run, the rover attempted some drilling at various depths and through a layer of sample material selected by the ExoMars team.
On Mars, the sample collected by the drill will be crushed into a fine powder and delivered to the analytical laboratory at the heart of the rover to analyse its mineralogy and chemistry.
With no summer break for the rover, upcoming tests at the Mars Terrain Simulator will involve the analysis of samples inside the rover’s analytical lab. A suite of instruments – MicrOmega, Raman and MOMA – will study the mineralogical and molecular composition of the soil.
During the real mission to the Red Planet, the results of this analysis could answer questions about the potential origin, evolution and distribution of life on Mars
Quelle: ESA
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Update: 23.08.2021
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ExoMars 2022 mission in final testing, ESA & Roscosmos prepare for approaching launch
The European Space Agency (ESA) and Roscosmos are preparing for the 2022 launch of the next mission in their joint ExoMars program, which is currently undergoing final testing before shipment to Kazakhstan for a launch in September next year.
The 2022 astrobiology mission will see the long-awaited Rosalind Franklin rover land on Mars with the help of the Russian Kazachok lander. The lander will also perform experiments on the Martian surface after deploying Rosalind Franklin as the two craft work together to search for signs of past life on the Red Planet.
ExoMars 2022 in final testing
After construction delays, missed Martian transfer windows, and the COVID-19 pandemic, Rosalind Franklin, Kazachok, and the other ExoMars 2022 mission systems have been completing important testing milestones ahead of shipment to Kazakhstan for launch on a Proton rocket next year.
Multiple unsuccessful parachute drop tests in 2019 and 2020 led engineers to redesign the system multiple times, leading to successful drop and deployment tests on June 24 and June 25, 2021. The new parachute design, if proven safe in additional tests, will be used to slow Kazachok and Rosalind Franklin during their descent to the Martian surface.
While testing of Rosalind Franklin and its associated landing systems has progressed, a test rover called the “Ground Test Model” (GTM) has been used by ESA to examine surface operations, science instruments, and terrain climbing/movement.
Testing with the GTM is performed at ALTEC in Turin, Italy. ESA teams have conducted testing with the rover’s NavCam, LocCam, PanCam, and CLUPI camera instruments, which will be used by Rosalind Franklin to traverse the Martian terrain.
Alongside the four camera instruments, ESA has also tested a variety of instruments that will be essential for collecting samples, drilling into Mars, and roving across challenging terrain. Instruments like WISDOM, MicrOmega, Raman, MOMA, and the large drill will all be extensively tested on the GTM to prepare ESA teams for the mission.
Outside of ALTEC, ESA has also completed balance testing with the entire ExoMars 2022 mission stack at Thales Alenia Space’s cleanroom facilities in Cannes, France.
To stay on a nominal trajectory during its journey to Mars, the ExoMars 2022 spacecraft, comprised of the carrier module, descent module (backshell and heatshield), Kazachok lander, and Rosalind Franklin rover, will spin at a constant rate of 2.75 revolutions per minute.
Balance testing ensures there is nothing inside and outside of the spacecraft that could cause it to move or “wobble” off course.
Rosalind Franklin and Kazachok are currently expected to ship to the Baikonur Cosmodrome in the coming months. Once there, they will undergo final launch preparations, including encapsulation and mating with the Proton carrier rocket.
Rosalind Franklin and Kazachok
In 2001, ESA began the ExoMars program with a plan to send a rover to Mars in 2009 and a follow-on Mars Sample Return mission in the years following.
This original vision for ExoMars would ultimately be canceled; however, in 2009, the Russian Federal Space Agency and ESA signed a contract to work together on two separate Mars exploration missions. At the time, Russia was planning to send their Fobos-Grunt mission to Martian moon Phobos. That mission would launch in 2011, with an upper stage failure stranding it in low Earth orbit before destructive reentry.
In April 2011, the MAX-C rover, another ExoMars rover being developed alongside the ExoMars rover (now Rosalind Franklin) by ESA, was officially canceled, and it was decided that only one rover would be sent to Mars.
The ExoMars rover was to be developed by ESA and feature a multitude of instruments from other agencies, companies, and ESA partners. At the time, NASA was set to participate in the rover’s development and operations on Mars, but the FY2013 budget terminated NASA’s participation in ExoMars.
After Roscosmos became a full partner with ESA, the final ExoMars plan was laid out. The Trace Gas Orbiter, which had been part of ExoMars for several years, was to be launched before the ExoMars rover and lander — both of which would be primarily developed, constructed, and tested by ESA, with Roscosmos providing two Proton launches and several instruments for the spacecraft.
In March 2014, with a launch scheduled for 2018, the British division of Airbus Defense and Space, the builder of the rover, began acquiring critical components for its construction. Funding for the ExoMars rover was approved by ESA member states in December 2014.
During this time, the development and construction of the Russian Kazachok lander also began. Kazachok, set to be the descent vehicle that will carry and land Rosalind Franklin on the surface, will host 13 instruments that will study the surface environment at the landing site.
In 2016, with the planned 2018 launch date creeping closer, ESA was struggling with scientific payload deliveries, and other goals for the mission were missing deadlines as well. Due to these issues, the ExoMars team announced they would be delaying the launch to July 2020.
As construction of the rover continued, one critical component of the rover was still missing — the name.
In summer 2018, ESA launched a public campaign to select a name for the rover. After reviewing submissions from the public, ESA announced on February 7, 2019, that the rover would be named Rosalind Franklin, a famed female scientist who researched and provided key contributions to the understanding of molecular structures in viruses, RNA, DNA, and more.
Following construction, the rover and Kazachok began an extensive testing campaign; however, in 2020, the COVID-19 pandemic forced work on the rover and lander to come to a halt, leading teams to miss critical deadlines needed to launch in 2020. As a result, the launch was delayed to 2022.
The nine instruments Rosalind Franklin will carry include the Panoramic Camera (PanCam), Infrared Spectrometer for ExoMars (ISEM), Water Ice Subsurface Deposits Observation on Mars (WISDOM), Adrom-RM, Close-Up Imager (CLUPI), Mars Multispectral Imager for Subsurface Studies (Ma_MISS), MicrOmega, Raman Laser Spectrometer (RLS), and Mars Organic Molecule Analyzer (MOMA).
Kazachok will carry 13 total instruments. These include the Lander Radioscience experiment (LaRa), Habitability, Brine, Irradiation and Temperature (HABIT), meteorological package (METEO-M), MAIGRET, Wave Analyzer Module (WAM), TSPP, interface, and memory unit (BIP), IR Fourier spectrometer (FAST), Active Detection of Radiation of Nuclei-ExoMars (ADRON-EM), multi-channel Diode-Laser Spectrometer for atmospheric investigations (M-DLS), radio thermometer for soil temperatures (PAT-M), dust particle size, impact, and atmospheric charging instrument suite (Dust Suite), seismometer (SEM), and the Gas chromatography-mass spectrometry for atmospheric analysis (MGAK) instruments.
The primary goal of ExoMars 2022 is to search for signs of past life, which the Trace Gas Orbiter (TGO) has been doing since 2016 from orbit. TGO “sniffs” the upper atmosphere of Mars for methane and other trace gases that could be evidence of past life.
ExoMars 2022 is scheduled to launch during a 12-day window in September 2022. Following liftoff, the ExoMars 2022 spacecraft (Rosalind Franklin, Kazachok, descent module, and carrier module) will coast through space for nearly eight months, waking up periodically to perform course correction burns and system health checks.
On June 10, 2023, the descent module will streak into the atmosphere of Mars and begin the entry, descent, and landing phase of the mission.
After entering the atmosphere, releasing the heatshield, dropping the rover and lander, lighting the lander’s engines, and touching down on the surface of Mars, Rosalind Franklin and Kazachok will begin surface operations.
ExoMars 2022 will launch on a Proton-M/Briz-M rocket from Baikonur Cosmodrome and is expected to land in the Oxia Planum region of Mars.
(Lead image: Artist’s impression of ESA’s Rosalind Franklin rover and Russia’s Kazachok lander. Credit: ESA/ATG medialab)
Quelle: NS
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Update: 17.09.2021
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First deep drilling success for ExoMars
ESA’s Rosalind Franklin twin rover on Earth has drilled down and extracted samples 1.7 metres into the ground – much deeper than any other martian rover has ever attempted.
The successful collection of soil from a hard stone and its delivery to the laboratory inside the rover marks a promising milestone for the ExoMars 2022 mission.
“The long-awaited success of the ExoMars drill on Earth would be a first in Mars exploration,” says David Parker, ESA’s director of human and robotic exploration. The deepest any drill has dug on the Red Planet to date is 7 cm.