posted 03-10-2016 12:58 PM               

ExoMars Trace Gas Orbiter and Schiaparelli Mission

The first mission of the ExoMars program, scheduled to arrive at Mars in 2016, consists of a Trace Gas Orbiter plus an entry, descent and landing demonstrator module, known as Schiaparelli. The main objectives of this mission are to search for evidence of methane and other trace atmospheric gases that could be signatures of active biological or geological processes and to test key technologies in preparation for ESA's contribution to subsequent missions to Mars.

The Orbiter and Schiaparelli will be launched together in March 2016 on a Proton rocket and will fly to Mars in a composite configuration. By taking advantage of the positioning of Earth and Mars the cruise phase can be limited to about seven months, with the pair arriving at Mars in October.

Three days before reaching the atmosphere of Mars, Schiaparelli will be ejected from the Orbiter towards the Red Planet. Schiaparelli will then coast towards its destination, enter the Martian atmosphere at 21,000 km/h, decelerate using aerobraking and a parachute, and then brake with the aid of a thruster system before landing on the surface of the planet.

From its coasting to Mars till its landing, Schiaparelli will communicate with the Orbiter. Once on the surface, the communications of Schiaparelli will be supported from Mars Express and from a NASA Relay Orbiter.

The ExoMars Orbiter will be inserted into an elliptical orbit around Mars and then sweep through the atmosphere to finally settle into a circular, approximately 400-km altitude orbit ready to conduct its scientific mission.

Trace Gas Orbiter

The Orbiter spacecraft is designed by ESA, while Roscosmos provides the launch vehicle. A scientific payload with instruments from Russia and Europe will be accommodated on the Orbiter to achieve its scientific objectives.

The Orbiter will perform detailed, remote observations of the Martian atmosphere, searching for evidence of gases of possible biological importance, such as methane and its degradation products. The instruments on board the Orbiter will carry out a variety of measurements to investigate the location and nature of sources that produce these gases.

The scientific mission is expected to begin in December 2017 and will run for five years. The Trace Gas Orbiter will also be used to relay data for the 2018 rover mission of the ExoMars program and until the end of 2022.

Schiaparelli: an entry, descent and landing demonstrator module

Schiaparelli, the ExoMars entry, descent and landing demonstrator module will provide Europe with the technology for landing on the surface of Mars with a controlled landing orientation and touchdown velocity.

The design of Schiaparelli maximizes the use of technologies already in development within the ExoMars program. These technologies include: special material for thermal protection, a parachute system, a radar Doppler altimeter system, and a final braking system controlled by liquid propulsion.

Schiaparelli is expected to survive on the surface of Mars for a short time by using the excess energy capacity of its batteries. The science possibilities of Schiaparelli are limited by the absence of long term power and the fixed amount of space and resources that can be accommodated within the module; however, a set of scientific sensors will be included to perform limited, but useful, surface science.

posted 03-10-2016 12:59 PM               

ExoMars 2016 meets its Proton rocket

In pictures: ExoMars 2016 spacecraft united with the Proton rocket.

On Saturday, March 5, the ExoMars Trace Gas Orbiter and the entry, descent and landing demonstrator module, known as Schiaparelli, which have been integrated with the Breeze-M upper stage, were transported by train to the area of the Baikonur Cosmosdrome where they were mated with the Proton launch vehicle that will carry them on the first part of their journey to Mars.

An electrical test of the Trace Gas Orbiter was carried out by Thales Alenia Space Italia to replicate the configuration that there will be on the launch pad.

Launch is scheduled for Monday, March 14 at 09:31 UTC (10:31 CET; 5:31 a.m. EDT).

posted 03-14-2016 04:50 AM               

Europe's ExoMars spacecraft launches to Red Planet to seek out signs of life

A European Mars mission launched on a Russian rocket Monday (March 14), sending an orbiter and an experimental lander on a journey to find signs of life on the Red Planet.

The ExoMars 2016 spacecraft – comprising the Trace Gas Orbiter and Schiaparelli, a landing demonstrator – lifted off at 5:31 a.m. EDT (0931 GMT) atop a Proton-M rocket from the Baikonur Cosmodrome in Kazakhstan. A joint mission between the European Space Agency (ESA) and Russia's Roscosmos, ExoMars 2016 marks the start of a new era of Mars exploration for Europe.

The ExoMars 2016 orbiter will search for signs of life from above Mars and for evidence of water-ice deposits on and just beneath the Martian surface.

Schiaparelli, which will separate from the orbiter just days before their arrival at Mars, will demonstrate that ESA has the technology to carry out a controlled landing, needed for further exploration of the planet.

posted 10-15-2016 12:46 PM               

Ready for the Red Planet

Next week, ESA's ExoMars has just a single chance to get captured by Mars' gravity. The spacecraft and the mission controllers who will make it so are ready for arrival.

The ExoMars Trace Gas Orbiter is on a multiyear mission to understand the methane and other gases in Mars' atmosphere at low levels and could be evidence for possible biological or geological activity.

The 3.7 tonne mothership is carrying the 577 kg Schiaparelli lander that will test key technologies in preparation for ESA's 2020 rover mission.

The pair have almost completed their 496 million km journey, and are now speeding towards a critical stage: releasing the lander on Sunday and the lander's descent and touchdown next Wednesday (Oct. 19), at the same time as the main craft begins circling the planet.

"They are now on a high-speed collision course with Mars, which is fine for the lander – it will stay on this path to make its controlled landing," says flight director Michel Denis at mission control in Darmstadt, Germany.

"However, to get the mothership into orbit, we must make a small but vital adjustment on 17 October to ensure it avoids the planet. And on 19 October it must fire its engine at a precise time for 139 minutes to brake into orbit.

"We get just a single chance."

Realtime mission control

Following months of intensive simulations, the team is now changing to 'real-time/full-time' shifts, and will work in the main control room.

The team will oversee separation, set for 14:42 GMT (16:42 CEST; 10:42 a.m. EDT) on Sunday (Oct. 16), the adjustment 12 hours later to avoid hitting Mars and, finally, the main engine burn starting at 13:05 GMT (15:05 CEST; 9:05 a.m. EDT) on Wednesday (Oct. 19).

A last pre-arrival correction was made Friday morning at 08:45 GMT (10:45 CEST) to ensure the craft is perfectly lined up for separation and arrival. The thruster burn delivered a tiny kick of 1.4 cm/s — all that was needed after an earlier series of extremely precise adjustments in July and September.

"This week, we uploaded the commands to fully charge the lander's batteries and prepare the orbiter's data-handling system as well as power and thruster system for separation and the subsequent trajectory tweak," says spacecraft operations manager Peter Schmitz.

"Next week, before the big burn, we will place it into a special 'failop' mode to minimize any risk that an on board glitch could interfere with the firing of the engine, which absolutely must happen at the planned time for us to get into orbit."

posted 10-19-2016 02:18 PM               

ExoMars TGO reaches Mars orbit while EDM situation under assessment

The Trace Gas Orbiter (TGO) of ESA's ExoMars 2016 has successfully performed the long 139-minute burn required to be captured by Mars and entered an elliptical orbit around the Red Planet, while contact has not yet been confirmed with the mission's test lander from the surface.

TGO's Mars orbit Insertion burn lasted from 13:05 to 15:24 GMT on 19 October, reducing the spacecraft's speed and direction by more than 1.5 km/s. The TGO is now on its planned orbit around Mars. European Space Agency teams at the European Space Operations Centre (ESOC) in Darmstadt, Germany, continue to monitor the good health of their second orbiter around Mars, which joins the 13-year old Mars Express.

The ESOC teams are trying to confirm contact with the Entry, Descent & Landing Demonstrator Module (EDM), Schiaparelli, which entered the Martian atmosphere some 107 minutes after TGO started its own orbit insertion manoeuvre.

The 577-kg EDM was released by the TGO at 14:42 GMT on 16 October. Schiaparelli was programmed to autonomously perform an automated landing sequence, with parachute deployment and front heat shield release between 11 and 7 km, followed by a retrorocket braking starting at 1100 m from the ground, and a final fall from a height of 2 m protected by a crushable structure.

Prior to atmospheric entry at 14:42 GMT, contact via the Giant Metrewave Radio Telescope (GMRT), the world's largest interferometric array, located near Pune, India, was established just after it began transmitting a beacon signal 75 minutes before reaching the upper layers of the Martian atmosphere. However, the signal was lost some time prior to landing.

A series of windows have been programmed to listen for signals coming from the lander via ESA'S Mars Express and NASA's Mars Reconnaissance Orbiter (MRO) and Mars Atmosphere & Volatile Evolution (MAVEN) probes. The Giant Metrewave Radio Telescope (GMRT) also has listening slots.

If Schiaparelli reached the surface safely, its batteries should be able to support operations for three to ten days, offering multiple opportunities to re-establish a communication link.

TGO is equipped with a suite of science instruments in order to study the Martian environment from orbit. Although mostly a technology demonstrator, Schiaparelli is also carrying a small science payload to perform some observations from ground.

ExoMars 2016 is the first part of a two-fold international endeavour conducted by ESA in cooperation with Roskosmos in Russia that will also encompass the ExoMars 2020 mission. Due in 2020, the second ExoMars mission will include a Russian lander and a European rover, which will drill down to 2 m underground to look for pristine organic material.

posted 10-20-2016 11:45 AM               

ESA's ExoMars orbiter rounds Red Planet, but Schiaparelli lander may be lost

Europe has a new spacecraft circling Mars, but the fate of its companion experimental lander is lost in the telemetry it transmitted, if not also physically lost on the Red Planet itself.

The European Space Agency's (ESA) ExoMars Trace Gas Orbiter (TGO) entered orbit on Wednesday (Oct. 19) after a seven-month journey from Earth. The spacecraft, which is designed to search for signs of life in the atmosphere, is considered a cornerstone of the ExoMars program, a joint effort between ESA and Russia's Roscosmos, which also includes sending a European rover and a Russian surface platform to the planet in 2020.

"TGO is now ready for science and at the same time ready for data relay, which we need for the 2020 mission," stated Jan Woerner, ESA Director General, in a press briefing on Thursday. "TGO is a cornerstone of the ExoMars 2016, as well as 2020 missions."

posted 10-21-2016 02:20 PM               

ESA's Schiaparelli Mars crash site located in NASA orbiter image

Europe's Schiaparelli lander not only slammed into Mars at "a considerable speed," but it may have exploded on impact, a new photo from a U.S. orbiter has revealed.

The European Space Agency (ESA) on Friday (Oct. 21) released the first image of what are likely the remains of its entry, descent and landing demonstrator, which attempted to touch down on the Red Planet Wednesday. The photos were taken by a low-resolution context camera on NASA's Mars Reconnaissance Orbiter (MRO).

"The image released today ... shows two new features on the surface when compared to an image from the same camera taken in May [of] this year," ESA officials wrote in a statement posted on its website.

posted 10-27-2016 11:14 AM               

Detailed images of Schiaparelli and its descent hardware on Mars

A high-resolution image taken by a NASA Mars orbiter this week reveals further details of the area where the ExoMars Schiaparelli module ended up following its descent on Oct. 19.

The latest image was taken on Oct. 25 by the high-resolution camera on NASA's Mars Reconnaissance Orbiter and provides close-ups of new markings on the planet's surface first found by the spacecraft's "context camera" last week.

Both cameras had already been scheduled to observe the center of the landing ellipse after the coordinates had been updated following the separation of Schiaparelli from ESA's Trace Gas Orbiter on Oct. 16. The separation maneuver, hypersonic atmospheric entry and parachute phases of Schiaparelli's descent went according to plan, the module ended up within the main camera's footprint, despite problems in the final phase.

The new images provide a more detailed look at the major components of the Schiaparelli hardware used in the descent sequence.

The main feature of the context images was a dark fuzzy patch of roughly 15 x 40 m, associated with the impact of Schiaparelli itself. The high-resolution images show a central dark spot, 2.4 m across, consistent with the crater made by a 300 kg object impacting at a few hundred km/h.

The crater is predicted to be about 50 cm deep and more detail may be visible in future images.

The asymmetric surrounding dark markings are more difficult to interpret. In the case of a meteoroid hitting the surface at 40,000­-80,000 km/h, asymmetric debris surrounding a crater would typically point to a low incoming angle, with debris thrown out in the direction of travel.

But Schiaparelli was traveling considerably slower and, according to the normal timeline, should have been descending almost vertically after slowing down during its entry into the atmosphere from the west.

It is possible the hydrazine propellant tanks in the module exploded preferentially in one direction upon impact, throwing debris from the planet's surface in the direction of the blast, but more analysis is needed to explore this idea further.

An additional long dark arc is seen to the upper right of the dark patch but is currently unexplained. It may also be linked to the impact and possible explosion.

Finally, there are a few white dots in the image close to the impact site, too small to be properly resolved in this image. These may or may not be related to the impact – they could just be "noise." Further imaging may help identify their origin.

Some 1.4 km south of Schiaparelli, a white feature seen in last week's context image is now revealed in more detail. It is confirmed to be the 12 m-diameter parachute used during the second stage of Schiaparelli's descent, after the initial heatshield entry into the atmosphere. Still attached to it, as expected, is the rear heatshield, now clearly seen.

The parachute and rear heatshield were ejected from Schiaparelli earlier than anticipated. Schiaparelli is thought to have fired its thrusters for only a few seconds before falling to the ground from an altitude of 2-4 km and reaching the surface at more than 300 km/h.

In addition to the Schiaparelli impact site and the parachute, a third feature has been confirmed as the front heatshield, which was ejected about four minutes into the six-minute descent, as planned.

The ExoMars and MRO teams identified a dark spot last week's image about 1.4 km east of the impact site and this seemed to be a plausible location for the front heatshield considering the timing and direction of travel following the module's entry.

The mottled bright and dark appearance of this feature is interpreted as reflections from the multilayered thermal insulation that covers the inside of the front heatshield. Further imaging from different angles should be able to confirm this interpretation.

The dark features around the front heatshield are likely from surface dust disturbed during impact.

Additional imaging by MRO is planned in the coming weeks. Based on the current data and observations made after 19 October, this will include images taken under different viewing and lighting conditions, which in turn will use shadows to help determine the local heights of the features and therefore a more conclusive analysis of what the features are.

A full investigation is now underway involving ESA and industry to identify the cause of the problems encountered by Schiaparelli in its final phase. The investigation started as soon as detailed telemetry transmitted by Schiaparelli during its descent had been relayed back to Earth by the Trace Gas Orbiter.

The full set of telemetry has to be processed, correlated and analyzed in detail to provide a conclusive picture of Schiaparelli's descent and the causes of the anomaly.

Until this full analysis has been completed, there is a danger of reaching overly simple or even wrong conclusions. For example, the team were initially surprised to see a longer-than-expected "gap" of two minutes in the telemetry during the peak heating of the module as it entered the atmosphere: this was expected to last up to only one minute. However, further processing has since allowed the team to retrieve half of the "missing" data, ruling out any problems with this part of the sequence.

The latter stages of the descent sequence, from the jettisoning of the rear shield and parachute, to the activation and early shut-off of the thrusters, are still being explored in detail. A report of the findings of the investigative team is expected no later than mid-November 2016.

The same telemetry is also an extremely valuable output of the Schiaparelli entry, descent and landing demonstration, as was the main purpose of this element of the ExoMars 2016 mission. Measurements were made on both the front and rear shields during entry, the first time that such data have been acquired from the back heatshield of a vehicle entering the martian atmosphere.

The team can also point to successes in the targeting of the module at its separation from the orbiter, the hypersonic atmospheric entry phase, and the parachute deployment at supersonic speeds, and the subsequent slowing of the module.

These and other data will be invaluable input into future lander missions, including the joint European-Russian ExoMars 2020 rover and surface platform.

Finally, the orbiter is working well and being prepared to make its first set of measurements on 20 November to calibrate its science instruments.

posted 11-03-2016 02:14 PM               

Schiaparelli crash site in color

New high-resolution images taken by a NASA orbiter show parts of the ExoMars Schiaparelli module and its landing site in color on the Red Planet.

Schiaparelli arrived in the Meridiani Planum region on Mars on 19 October, while its mothership began orbiting the planet. The Trace Gas orbiter will make its first science observations during two of its highly elliptical circuits around Mars – corresponding to eight days – starting on 20 November, including taking its first images of the planet since arriving.

The new image of Schiaparelli and its hardware components was taken by NASA's Mars Reconnaissance Orbiter, or MRO, on 1 November. The main impact site is now captured in the central portion of the swath that is imaged by the high-resolution camera through three filters, enabling a colour image to be constructed.

In addition, the image of 1 November was taken looking slightly to the west, while the earlier image was looking to the east, providing a contrasting viewing geometry.

Indeed, the latest image set sheds new light on some of the details that could only be speculated from the first look last week.

For example, a number of the bright white spots around the dark region interpreted as the impact site are confirmed as real objects – they are not likely to be imaging 'noise' – and therefore are most likely fragments of Schiaparelli.

Interestingly, a bright feature can just be made out in the place where the dark crater was identified in last week's image. This may be associated with the module, but the images so far are not conclusive.

A bright fuzzy patch revealed in the color image alongside the dark streaks to the west of the crater could be surface material disturbed in the impact or from a subsequent explosion or explosive decompression of the module's fuel tanks, for example.

About 0.9 km to the south, the parachute and rear heatshield have also now been imaged in color. In the time that has elapsed since the last image was taken on 25 October, the outline of the parachute has changed. The most logical explanation is that it has been shifted in the wind, in this case slightly to the west. This phenomenon was also observed by MRO in images of the parachute used by NASA's Curiosity rover.

A stereo reconstruction of this image in the future will also help to confirm the orientation of the rear heatshield. The pattern of bright and dark patches suggest it is sitting such that we see the outside of the heatshield and the signature of the way in which the external layer of insulation has burned away in some parts and not others – as expected.

Finally, the front heatshield has been imaged again in black and white – its location falls outside of the color region imaged by MRO – and shows no changes. Because of the different viewing geometry between the two image sets, this confirms that the bright spots are not specular reflections, and must therefore be related to the intrinsic brightness of the object. That is, it is most likely the bright multilayer thermal insulation that covers the inside of the front heatshield, as suggested last week.

Further imaging is planned in about two weeks, and it will be interesting to see if any further changes are noticed.

The images may provide more pieces of the puzzle as to what happened to Schiaparelli as it approached the martian surface.

Following its successful atmospheric entry and subsequent slowing due to heatshield and parachute deceleration, the internal investigation into the root cause of the problems encountered by Schiaparelli in the latter stages of its six-minute descent continues. An independent inquiry board has been initiated.

posted 11-23-2016 01:44 PM               

Schiaparelli landing investigation makes progress

Good progress has been made in investigating the ExoMars Schiaparelli anomaly of 19 October. A large volume of data recovered from the Mars lander shows that the atmospheric entry and associated braking occurred exactly as expected.

The parachute deployed normally at an altitude of 12 km and a speed of 1730 km/h. The vehicle's heatshield, having served its purpose, was released at an altitude of 7.8 km.

As Schiaparelli descended under its parachute, its radar Doppler altimeter functioned correctly and the measurements were included in the guidance, navigation and control system. However, saturation – maximum measurement – of the Inertial Measurement Unit (IMU) had occurred shortly after the parachute deployment. The IMU measures the rotation rates of the vehicle. Its output was generally as predicted except for this event, which persisted for about one second – longer than would be expected.

When merged into the navigation system, the erroneous information generated an estimated altitude that was negative – that is, below ground level. This in turn successively triggered a premature release of the parachute and the backshell, a brief firing of the braking thrusters and finally activation of the on-ground systems as if Schiaparelli had already landed. In reality, the vehicle was still at an altitude of around 3.7 km.

This behavior has been clearly reproduced in computer simulations of the control system's response to the erroneous information.

"This is still a very preliminary conclusion of our technical investigations," says David Parker, ESA's Director of Human Spaceflight and Robotic Exploration. "The full picture will be provided in early 2017 by the future report of an external independent inquiry board, which is now being set up, as requested by ESA's Director General, under the chairmanship of ESA's Inspector General.

"But we will have learned much from Schiaparelli that will directly contribute to the second ExoMars mission being developed with our international partners for launch in 2020."

"ExoMars is extremely important for European science and exploration," says Roberto Battiston, President of Italy's ASI space agency. "Together with all the participating states in the programme, we will work towards the successful completion of the second ExoMars mission.

"ESA and ASI's strong partnership will continue to be instrumental in this valuable and exciting European mission."

Meanwhile, scientific data from the instruments aboard Schiaparelli during the entry, plus tracking data from the ExoMars Trace Gas Orbiter, Mars Express and India's Giant Metre Wave Radio Telescope India have been passed to the science teams. These data will contribute to understanding of the Red Planet and especially its atmosphere.

The Trace Gas Orbiter is starting its first series of science observations since arriving at the Red Planet on 19 October, taking advantage of the initial parking orbit before beginning a long series of aerobraking maneuvers that will deliver the spacecraft to its operational orbit towards the end of 2017.

posted 11-29-2016 08:26 AM               

First views of Mars show potential for ESA's new orbiter

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 endeavor between ESA and Roscosmos, arrived at Mars on 19 October. 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 20–28 November 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 vapor, 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.

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.

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.

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.

The camera team also completed a quick first test of producing a 3D reconstruction of a region in Noctis Labyrinthus, from a stereo pair of images.

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."

posted 05-25-2017 08:09 AM               

Schiaparelli landing investigation completed

The inquiry into the crash-landing of the ExoMars Schiaparelli module has concluded that conflicting information in the onboard computer caused the descent sequence to end prematurely.

The Schiaparelli entry, descent and landing demonstrator module separated from its mothership, the Trace Gas Orbiter, as planned on 16 October last year, and coasted towards Mars for three days.

Much of the six-minute descent on 19 October went as expected: the module entered the atmosphere correctly, with the heatshield protecting it at supersonic speeds. Sensors on the front and back shields collected useful scientific and engineering data on the atmosphere and heatshield.

Telemetry from Schiaparelli was relayed to the main craft, which was entering orbit around the Red Planet at the same time – the first time this had been achieved in Mars exploration. This realtime transmission proved invaluable in reconstructing the unfolding chain of events.

At the same time as the orbiter recorded Schiaparelli's transmissions, ESA's Mars Express orbiter also monitored the lander's carrier signal, as did the Giant Metrewave Radio Telescope in India.

In the days and weeks afterwards, NASA's Mars Reconnaissance Orbiter took a number of images identifying the module, the front shield, and the parachute still connected with the backshield, on Mars, very close to the targeted landing site.

The images suggested that these pieces of hardware had separated from the module as expected, although the arrival of Schiaparelli had clearly been at a high speed, with debris strewn around the impact site.

The independent external inquiry, chaired by ESA's Inspector General, has now been completed.

It identifies the circumstances and the root causes, and makes general recommendations to avoid such defects and weaknesses in the future. The report summary can be downloaded here.

Around three minutes after atmospheric entry the parachute deployed, but the module experienced unexpected high rotation rates. This resulted in a brief 'saturation' – where the expected measurement range is exceeded – of the Inertial Measurement Unit, which measures the lander's rotation rate.

The saturation resulted in a large attitude estimation error by the guidance, navigation and control system software. The incorrect attitude estimate, when combined with the later radar measurements, resulted in the computer calculating that it was below ground level.

This resulted in the early release of the parachute and back-shell, a brief firing of the thrusters for only 3 sec instead of 30 sec, and the activation of the on-ground system as if Schiaparelli had landed. The surface science package returned one housekeeping data packet before the signal was lost.

In reality, the module was in free-fall from an altitude of about 3.7 km, resulting in an estimated impact speed of 540 km/h.

The Schiaparelli Inquiry Board report noted that the module was very close to landing successfully at the planned location and that a very important part of the demonstration objectives were achieved. The flight results revealed required software upgrades, and will help improve computer models of parachute behaviour.

"The realtime relay of data during the descent was crucial to provide this in-depth analysis of Schiaparelli's fate," says David Parker, ESA's Director of Human Spaceflight and Robotic Exploration.

"We are extremely grateful to the teams of hard-working scientists and engineers who provided the scientific instruments and prepared the investigations on Schiaparelli, and deeply regret that the results were curtailed by the untimely end of the mission.

"There were clearly a number of areas that should have been given more attention in the preparation, validation and verification of the entry, descent and landing system.

"We will take the lessons learned with us as we continue to prepare for the ExoMars 2020 rover and surface platform mission. Landing on Mars is an unforgiving challenge but one that we must meet to achieve our ultimate goals."

"Interestingly, had the saturation not occurred and the final stages of landing had been successful, we probably would not have identified the other weak spots that contributed to the mishap," notes Jan Woerner, ESA's Director General. "As a direct result of this inquiry we have discovered the areas that require particular attention that will benefit the 2020 mission."

ExoMars 2020 has since passed an important review confirming it is on track to meet the launch window. Having been fully briefed on the status of the project, ESA Member States at the Human Spaceflight, Microgravity and Exploration Program Board reconfirmed their commitment to the mission, which includes the first Mars rover dedicated to drilling below the surface to search for evidence of life on the Red Planet.

Meanwhile the Trace Gas Orbiter has begun its year-long aerobraking in the fringes of the atmosphere that will deliver it to its science orbit in early 2018. The spacecraft has already shown its scientific instruments are ready for work in two observing opportunities in November and March.

In addition to its main goal of analyzing the atmosphere for gases that may be related to biological or geological activity, the orbiter will also act as a relay for the 2020 rover and surface platform.

The ExoMars program is a joint endeavor between ESA and Roscosmos.

posted 04-11-2019 10:00 AM               

First results from the ExoMars Trace Gas Orbiter

New evidence of the impact of the recent planet-encompassing dust storm on water in the atmosphere, and a surprising lack of methane, are among the scientific highlights of the ExoMars Trace Gas Orbiter's first year in orbit.

Two papers are published in the journal Nature on 10 April 2019 describing the new results, and reported in a dedicated press briefing at the European Geosciences Union in Vienna.

A third paper, submitted to the Proceedings of the Russian Academy of Science, presents the most detailed map ever produced of water-ice or hydrated minerals in the shallow subsurface of Mars.

The joint ESA-Roscosmos ExoMars Trace Gas Orbiter, or TGO, arrived at the Red Planet in October 2016, and spent more than one year using the aerobraking technique needed to reach its two-hour science orbit, 400 km above the surface of Mars.

"We are delighted with the first results from the Trace Gas Orbiter," says Håkan Svedhem, ESA's TGO project scientist.

"Our instruments are performing extremely well and even within the first few months of observation were already providing exquisite data to a much higher level than previously achieved."

Above: Overview of the three new results presented April 10, 2019 by the ExoMars Trace Gas Orbiter teams. While results from the imaging system CaSSIS have been presented previously, this release covers the first analysis of the Mars atmosphere and subsurface. (ESA)

TGO's main science mission began at the end of April 2018, just a couple of months before the start of the global dust storm that would eventually lead to the demise of NASA's Opportunity rover after 15 years roving the martian surface.

Spacecraft in orbit, however, were able to make unique observations, with TGO following the onset and development of the storm and monitoring how the increase in dust affected the water vapour in the atmosphere – important for understanding the history of water at Mars over time.

Exploiting the dust storm

Two spectrometers onboard – NOMAD and ACS – made the first high-resolution solar occultation measurements of the atmosphere, looking at the way sunlight is absorbed in the atmosphere to reveal the chemical fingerprints of its ingredients.

This enabled the vertical distribution of water vapour and 'semi-heavy' water – with one hydrogen atom replaced by a deuterium atom, a form of hydrogen with an additional neutron – to be plotted from close to the martian surface to above 80 km altitude. The new results track the influence of dust in the atmosphere on water, along with the escape of hydrogen atoms into space.

"In the northern latitudes we saw features such as dust clouds at altitudes of around 25–40 km that were not there before, and in southern latitudes we saw dust layers moving to higher altitudes," says Ann Carine Vandaele, principal investigator of the NOMAD instrument at the Royal Belgian Institute for Space Aeronomy.

"The enhancement of water vapour in the atmosphere happened remarkably quickly, over just a few days during the onset of the storm, indicating a swift reaction of the atmosphere to the dust storm."

Above: The ExoMars Trace Gas Orbiter's main science mission began at the end of April 2018, just a couple of months before the start of the global dust storm that engulfed the planet. TGO followed the onset and development of the storm and monitored how the increase in dust affected the water vapour in the atmosphere. (ESA)

The observations are consistent with global circulation models. Dust absorbs the Sun's radiation, heating the surrounding gas and causing it to expand, in turn redistributing other ingredients – like water – over a wider vertical range. A higher temperature contrast between equatorial and polar regions is also set up, strengthening atmospheric circulation. At the same time, thanks to the higher temperatures, fewer water-ice clouds form – normally they would confine water vapour to lower altitudes.

The teams also made the first observation of semi-heavy water simultaneously with water vapour, providing key information on the processes that control the amount of hydrogen and deuterium atoms escaping to space. It also means the deuterium-to-hydrogen (D/H) ratio can be derived, which is an important marker for the evolution of the water inventory on Mars.

"We see that water, deuterated or not, is very sensitive to the presence of ice clouds, preventing it from reaching atmospheric layers higher up. During the storm, water reached much higher altitudes," says Ann Carine."This was theoretically predicted by models for a long time but this is the first time we have been able to observe it."

Since the D/H ratio is predicted to change with the season and with latitude, TGO's continued regional and seasonal measurements are expected to provide further evidence of the processes at play.

Methane mystery plot thickens

The two complementary instruments also started their measurements of trace gases in the martian atmosphere. Trace gases occupy less than one percent of the atmosphere by volume, and require highly precise measurement techniques to determine their exact chemical fingerprints in the composition. The presence of trace gases is typically measured in 'parts per billion by volume' (ppbv), so for the example for Earth's methane inventory measuring 1800 ppbv, for every billion molecules, 1800 are methane.

Methane is of particular interest for Mars scientists, because it can be a signature of life, as well as geological processes – on Earth, for example, 95% of methane in the atmosphere comes from biological processes. Because it can be destroyed by solar radiation on timescales of several hundred years, any detection of the molecule in present times implies it must have been released relatively recently – even if the methane itself was produced millions or billions of years ago and remained trapped in underground reservoirs until now. In addition, trace gases are mixed efficiently on a daily basis close to the planet's surface, with global wind circulation models dictating that methane would be mixed evenly around the planet within a few months.

Reports of methane in the martian atmosphere have been intensely debated because detections have been very sporadic in time and location, and often fell at the limit of the instruments' detection limits. ESA's Mars Express contributed one of the first measurements from orbit in 2004, at that time indicating the presence of methane amounting to 10 ppbv.

Earth-based telescopes have also reported both non-detections and transient measurements up to about 45 ppbv, while NASA's Curiosity rover, exploring Gale Crater since 2012, has suggested a background level of methane that varies with the seasons between about 0.2 and 0.7 ppbv – with some higher level spikes. More recently, Mars Express observed a methane spike one day after one of Curiosity's highest-level readings.

Above: The ExoMars Trace Gas Orbiter's first analysis of the martian atmosphere at various points around the globe finds an upper limit of methane 10–100 times less than all previous reported detections. The measured data show the sensitivity of the ACS and NOMAD instruments when looking at other molecules, such as water, while methane is apparently absent: the results suggest an upper limit of 0.05 parts per billion (ppbv). (ESA)

The new results from TGO provide the most detailed global analysis yet, finding an upper limit of 0.05 ppbv, that is, 10–100 times less methane than all previous reported detections. The most precise detection limit of 0.012 ppbv was achieved at 3 km altitude.

As an upper limit, 0.05 ppbv still corresponds to up to 500 tons of methane emitted over a 300 year predicted lifetime of the molecule when considering atmospheric destruction processes alone, but dispersed over the entire atmosphere, this is extremely low.

"We have beautiful, high-accuracy data tracing signals of water within the range of where we would expect to see methane, but yet we can only report a modest upper limit that suggests a global absence of methane," says ACS principal investigator Oleg Korablev from the Space Research Institute, Russian Academy of Sciences, Moscow.

"The TGO's high-precision measurements seem to be at odds with previous detections; to reconcile the various datasets and match the fast transition from previously reported plumes to the apparently very low background levels, we need to find a method that efficiently destroys methane close to the surface of the planet."

"Just as the question of the presence of methane and where it might be coming from has caused so much debate, so the issue of where it is going, and how quickly it can disappear, is equally interesting," says Håkan.

"We don't have all the pieces of the puzzle or see the full picture yet, but that is why we are there with TGO, making a detailed analysis of the atmosphere with the best instruments we have, to better understand how active this planet is – whether geologically or biologically."

Above: This graphic summarises significant measurement attempts of methane at Mars. Reports of methane have been made by Earth-based telescopes, ESA's Mars Express from orbit around Mars, and NASA's Curiosity located on the surface at Gale Crater; they have also reported measurement attempts with no or very little methane detected. More recently, the ESA-Roscosmos ExoMars Trace Gas Orbiter reported an absence of methane, and provided a very low upper limit. (ESA)

Best map of shallow subsurface water

While the lively debate on the nature and presence of methane continues, one sure thing is that water once existed on Mars – and still does in the form of water-ice, or as water-hydrated minerals. And where there was water, there might have been life.

To help understand the location and history of water on Mars, TGO's neutron detector FREND is mapping the distribution of hydrogen in the uppermost metre of the planet's surface. Hydrogen indicates the presence of water, being one of the constituents of the water molecule; it can also indicate water absorbed into the surface, or minerals that were formed in the presence of water.

The instrument's mapping task will take about one Mars year – almost two Earth years – to produce the best statistics to generate the highest quality map. But the first maps presented based on just a few month's data already exceed the resolution of previous measurements.

Above: The FREND neutron spectrometer on the ExoMars Trace Gas Orbiter has started mapping the distribution of hydrogen in the uppermost metre of the martian's surface. Hydrogen indicates the presence of water, being one of the constituents of the water molecule; it can also indicate water absorbed into the surface, or minerals that were formed in the presence of water. A map produced from 131 days data, from 3 May to 10 September 2018, is presented here, covering the globe from 70 degrees N to 70 degrees S. (ESA)

"In just 131 days the instrument had already produced a map that has a higher resolution than that of the 16 years data from its predecessor onboard NASA's Mars Odyssey – and it is set to continue getting better," says Igor Mitrofanov, principal investigator of the FREND instrument at the Space Research Institute, Russian Academy of Sciences, Moscow.

Aside from the obviously water-rich permafrost of the polar regions, the new map provides more refined details of localised 'wet' and 'dry' regions. It also highlights water-rich materials in equatorial regions that may signify the presence of water-rich permafrost in present times, or the former locations of the planet's poles in the past.

"The data is continually improving and we will eventually have what will become the reference data for mapping shallow subsurface water-rich materials on Mars, crucial for understanding the overall evolution of Mars and where all the present water is now," adds Igor. "It is important for the science on Mars, and it is also valuable for future Mars exploration."

"We have already been enjoying beautiful images and stereo views of Mars thanks to the TGO's imaging system and now we are delighted to share the first look at data from the other instruments," concludes Håkan.

"We have a promising future in contributing to the many fascinating aspects of Mars science, from the distribution of subsurface water, to active surface processes and to the mysteries of the martian atmosphere."

posted 12-16-2021 09:14 AM               

ExoMars discovers hidden water in Mars' Grand Canyon

The ESA-Roscosmos ExoMars Trace Gas Orbiter has spotted significant amounts of water at the heart of Mars' dramatic canyon system, Valles Marineris.

Above: Valles Marineris, seen at an angle of 45 degrees to the surface in near-true colour and with four times vertical exaggeration. The image covers an area of 630 000 sq km with a ground resolution of 100 m per pixel.

The water, which is hidden beneath Mars' surface, was found by the Trace Gas Orbiter (TGO)'s FREND instrument, which is mapping the hydrogen – a measure of water content – in the uppermost metre of Mars' soil.

While water is known to exist on Mars, most is found in the planet's cold polar regions as ice. Water ice is not found exposed at the surface near the equator, as temperatures here are not cold enough for exposed water ice to be stable.

Missions including ESA's Mars Express have hunted for near-surface water – as ice covering dust grains in the soil, or locked up in minerals – at lower latitudes of Mars, and found small amounts. However, such studies have only explored the very surface of the planet; deeper water stores could exist, covered by dust.

"With TGO we can look down to one metre below this dusty layer and see what's really going on below Mars' surface – and, crucially, locate water-rich 'oases' that couldn't be detected with previous instruments," says Igor Mitrofanov of the Space Research Institute of the Russian Academy of Sciences in Moscow, Russia; lead author of the new study; and principal investigator of the FREND (Fine Resolution Epithermal Neutron Detector) neutron telescope.

"FREND revealed an area with an unusually large amount of hydrogen in the colossal Valles Marineris canyon system: assuming the hydrogen we see is bound into water molecules, as much as 40% of the near-surface material in this region appears to be water."

The water-rich area is about the size of the Netherlands and overlaps with the deep valleys of Candor Chaos, part of the canyon system considered promising in our hunt for water on Mars.

Tracking neutrons

Igor and colleagues analysed FREND observations ranging from May 2018 to February 2021, which mapped the hydrogen content of Mars' soil by detecting neutrons rather than light.

"Neutrons are produced when highly energetic particles known as 'galactic cosmic rays' strike Mars; drier soils emit more neutrons than wetter ones, and so we can deduce how much water is in a soil by looking at the neutrons it emits," adds co-author Alexey Malakhov, also of the Space Research Institute of the Russian Academy of Sciences. "FREND's unique observing technique brings far higher spatial resolution than previous measurements of this type, enabling us to now see water features that weren't spotted before.

"We found a central part of Valles Marineris to be packed full of water – far more water than we expected. This is very much like Earth's permafrost regions, where water ice permanently persists under dry soil because of the constant low temperatures."

Above: ExoMars Trace Gas Orbiter maps water-rich region of Valles Marineris.

This water could be in the form of ice, or water that is chemically bound to other minerals in the soil. However, other observations tell us that minerals seen in this part of Mars typically contain only a few percent water, much less than is evidenced by these new observations. "Overall, we think this water more likely exists in the form of ice," says Alexey.

Water ice usually evaporates in this region of Mars due to the temperature and pressure conditions near the equator. The same applies to chemically bound water: the right combination of temperature, pressure and hydration must be there to keep minerals from losing water. This suggests that some special, as-yet-unclear mix of conditions must be present in Valles Marineris to preserve the water – or that it is somehow being replenished.

"This finding is an amazing first step, but we need more observations to know for sure what form of water we're dealing with," adds study co-author Håkan Svedhem of ESA's ESTEC in the Netherlands, and former ESA project scientist for the ExoMars Trace Gas Orbiter.

"Regardless of the outcome, the finding demonstrates the unrivalled abilities of TGO's instruments in enabling us to 'see' below Mars' surface – and reveals a large, not-too-deep, easily exploitable reservoir of water in this region of Mars."

Future exploration

As most future missions to Mars plan to land at lower latitudes, locating such a reservoir of water here is an exciting prospect for future exploration.

While Mars Express has found hints of water deeper underground in Mars' mid-latitudes, alongside deep pools of liquid water under Mars' south pole, these potential stores lie up to a few kilometres below ground, making them less exploitable and accessible to exploration than any found just below the surface.

The finding also makes Valles Marineris an even more promising target for future human exploration missions to the planet. The largest canyon in the Solar System, Valles Marineris is arguably Mars' most dramatic landscape, and a feature that is often compared to Earth's Grand Canyon – despite being some ten times longer and five times deeper.

"This result really demonstrates the success of the joint ESA-Roscosmos ExoMars programme," says Colin Wilson, ESA's ExoMars Trace Gas Orbiter project scientist.

"Knowing more about how and where water exists on present-day Mars is essential to understand what happened to Mars' once-abundant water, and helps our search for habitable environments, possible signs of past life, and organic materials from Mars' earliest days."

TGO launched in 2016 as the first of two launches under the ExoMars programme. The orbiter will be joined in 2022 by a European rover, Rosalind Franklin, and a Russian surface platform, Kazachok, and all will work together to understand whether life has ever existed on Mars.