Space Sunday: the sands of Mars and Planet Nine

The spread of the 2018 dust storm as seen by NASA’s Mars Reconnaissance Orbiter between May 31st and June 10th. The black gaps in the images indicate parts of the planet’s surface not captured in the individual images making up this time-lapse view. Note the position of the Opportunity and Curiosity rovers. Credit: NASA / MSSS

Dust storms on Mars are not unusual event; they occur in both hemispheres with the changing of the seasons, and can even grow to encompass the entire planet.

Just such world-girdling dust storm occurred in 1971, and was caught by the cameras on NASA’s Mariner 9 space vehicle when it arrived in the vicinity of Mars in November of that year. The images Mariner 9 returned from Mar as it entered orbit (becoming in the process the first man-made object to orbit another planet) show the entire surface of Mars totally obscured by a blanket of dust that reached high up into the atmosphere. It took some two months for the storms to abate – although scientists were treated to Mars gradually revealing itself to Mariner 9’s camera as the dust slowly settled, starting with the high peaks of Olympus Mons and the Tharsis Ridge volcanoes, which rise up to 25 kilometres above the mean surface level of Mars.

In 2001, the Hubble Space Telescope (HST) reveal just how all-encompassing these more massive storms on Mars can be, when it took two images of Mars just three months apart. In one, surface features are clearly visible; in the second, Mars appears to be devoid of any detail.

These two images, captured 3 months apart by the Hubble Space Telescope in 2001, shoe how all-encompassing the more extreme dust storms on Mars can be. Note that in both images, south is at the top . Credit: NASA / The Hubble Heritage Team

Now, another dust storm is engulfing a huge swathe of Mars. It grew quickly in the opening week and a half of June, While it has not – as yet – engulfed the entire planet, it is raising massive mounts of dust high into the Martian atmosphere, marking it as the “thickest” dust storm witnessed on Mars.

Of to two rovers currently operating on Mars, the Mars Exploration Rover Opportunity is particularly impacted by storms of this nature as it is solar-powered. Such is the volume of dust lifted into the Martian atmosphere when these more extreme storms occur that they can severely limit Oppy’s ability to gather sunlight to charge its batteries.

This is not the first such dust storm Oppy has encountered; in 2007, a large-scale storm resulted in a severe degradation in the amount of sunlight reaching the Martian surface where the rover was operating. At that time, we were treated to some remarkable images of just how all-pervasive the dust can become when lifted into the tenuous Martian atmosphere.

This series of images show the onset of a severe dust storm, as seen by NASA’s Opportunity rover in 2007. On the left, Sol 1205, is “normal” daylight conditions. The remain shots show the reduction in daylight between Sol 1220 and Sol 12035. Credit: NASA / Cornell University

Even so the current storm is perhaps the most severe Oppy has had to face. So much so that even though the decision was quickly made to suspend all science gathering operations as it explores Endeavour Crater, and so reduce its power output, the rover has since switched itself into a further “safe” mode of power conservation.

This  kind of more massive storm is particularly prone to occurring when summer comes to one of the hemispheres (in this case, the southern hemisphere). At this time, the increased sunlight warming the atmosphere causes an increase in wind activity, which results in more dust being lifted into the atmosphere. For so reason, this dust causes the winds to persist  – and even increase, lifting more dust, and a feedback loop is created, turning the process into a self-driving storm that can take weeks or months to die down.

A couple of interesting points with these dust storms is that firstly, and for those familiar with the Matt Damon vehicle The Martian, the winds are nowhere near as violent as portrayed by that film. While wind speeds during these storms can reach speeds of 96-160 km/h (60-100 mph), the Martian atmosphere is so tenuous, the overall effect of such wind speeds is akin to a stiff breeze here on Earth. The second point is that while they do reduce the amount of sunlight reaching the surface of Mars, the dust is an effective insulator, both reducing the amount of heat being radiated away from Mars whilst simultaneously absorbing solar radiation, both of which serve to raise ambient surface temperatures.

This latter point is in part good news for Oppy, as it helps reduce the rover’s power outlay in keeping itself and its instruments warm. However, given that such intense storms can last for periods of several weeks to months at a time, there is genuine concerns as to how well Opportunity might survive if this storm is particularly drawn out, leaving the MER team on Earth reasonably confident the rover will be able to survive the storm without its systems becoming too cold to be restarted.

By June 10th, the storm had grown to a size where it was starting to make itself felt in Gale Crater, where NASA is operating the Mars Science Laboratory rover Curiosity, although the effects haven’t been as great as around Endeavour Crater, which Opportunity has been exploring. When it comes to dust storms, Curiosity has a significant advantage over Opportunity in that it is nuclear powered and is thus its power systems aren’t affected by any loss of  sunlight.

The dust storm reaches Gale crater: on the left, a true colour image from Curiosity’s Mastcam taken of the east-north-east rim of Gale Crater taken on June 7th, 2018 (Sol 2074). On the right, the same view seen three days later, on June 10th, 2018 (Sol 2077). Credit: NASA / MSSS

By the time the dust storm reach Gale Crater, it was blanketing to 35 million square kilometres (14 million sq miles) of the Martian surface – or roughly one-quarter of the entire planet, and it was still growing. As well as bing observed by the two surface rovers, it is also being watched from space by the combined network of NASA’s Mars Reconnaissance Orbiter (MRO), Mars Odyssey and MAVEN space vehicles, as well as Europe’s Mars Express mission and India’s Mars Observer Mission.

Observing and probing this kind of storm is seen as vital on a number of counts. In the first place, the precise mechanism that causes the feedback loop of wind and dust mentioned above isn’t really understood, so seeing storms like the develop and abate can help scientists to fill-in the blanks. In addition, and as NASA’s Mars Programme Office chief scientist Rich Zurek explains:

Studying their physics is critical to understanding the ancient and modern Martian climate. Each observation of these large storms brings us closer to being able to model these events, and maybe, someday, being able to forecast them. That would be like forecasting El Niño events on Earth, or the severity of upcoming hurricane seasons.

This latter point is particularly important in terms of planning for future missions – including any human mission to Mars. Being able to predict the rises and potential scope of these storms could go a long way to ensuring human safety on Mars. However, for the duration of this storm, all eyes are on little Opportunity, caught in the midst of it, with the hope that the rover will come through the storm able to resume its record-breaking 14+ years of operations on Mars.

Continue reading “Space Sunday: the sands of Mars and Planet Nine”

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Space Sunday: of molecules, meteorites and missions

In 1996, amidst a huge fanfare which included a statement by then US President Bill Clinton, a team of researchers announced they had discovered evidence of past Martian microbial life within a meteorite called ALH84001, discovered in the Allen Hills of Antarctica in 1984.

The claim lead to a high degree controversy, with many scientists disputing the findings of the original team. While that discovery has never been conclusively disproved, it has never been verified, either. However, it has – alongside the controversial results from two of the Viking Lander experiments in the 1970s – encouraged teams researching the potential for microbial life on Mars to be cautious in their work.

So it was with a sense of excitement that on Thursday, June 7th, 2018, NASA announced that the Mars Science Laboratory (MSL) Curiosity rover has once again found potential evidence of both organic molecules and methane on Mars. The news came via two papers Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars and Background levels of methane in Mars’ atmosphere show strong seasonal variations.

In the first paper, the authors indicate how Curiosity’s Sample Analysis at Mars (SAM) suite detected traces of methane in drill samples it took from Martian rocks in 2016. Once these rocks were heated, they released an array of organics and volatiles similar to how organic-rich sedimentary rocks do on Earth – where similar deposits are indications of fossilised organic life.

What is particularly exciting is the first paper indicates that the material discovered on Mars is similar to terrestrial kerogen, a solid organic matter found in sedimentary rocks. Comprising an estimated 1016 tons of carbon, Kerogen on Earth exceeds the organic content of all living matter on Earth by a factor of 10,000.

NASA’s Curiosity rover has discovered ancient organic molecules on Mars, embedded within sedimentary rocks that are billions of years old. Credit: NASA Goddard Space Flight Centre

Essentially, want happens on Earth is that organic material gets laid down within the sedimentary layers, then over the aeons, fluid flowing thought the rock initiates chemical reactions to break down the organic deposits until only the insoluble  kerogen is left. It has already been established that Gale Crater was once the home of several liquid water lakes, and also that perchlorate salt – particularly good at breaking down organics – is present on Mars. Hence why the discovery of the kerogen-like material on Mars is a cause for excitement – it could be a similar process to that seen on Earth is present.

While the team responsible for the styudy point out the material SAM has found is similar to an insoluble material discovered in tiny meteorites known to fall on Mars, that it might have formed naturally on the planet is somewhat strengthened by the fact Curiosity has previously confirmed Gale Crater contains the chemical building blocks and energy sources that are necessary for life. However, the legacy of ALH84001 urge caution when dealing with these findings from the rover, as one of the authors of the first paper explained.

Curiosity has not determined the source of the organic molecules. Whether it holds a record of ancient life, was food for life, or has existed in the absence of life, organic matter in materials holds chemical clues to planetary conditions and processes… The Martian surface is exposed to radiation from space. Both radiation and harsh chemicals break down organic matter. Finding ancient organic molecules in the top five centimetres of rock that was deposited when Mars may have been habitable, bodes well for us to learn the story of organic molecules on Mars with future missions that will drill deeper.

Jennifer Eigenbrode, co-author, Organic matter preserved in 3-billion-year-old mudstones at Gale crater, Mars

In the second paper, scientists describe the discovery of seasonal variations in methane in the Martian atmosphere over the course of nearly three Mars years, which is almost six Earth years. This variation was also detected by Curiosity’s SAM instrument suite over the 3-year period.

This image illustrates possible ways methane might get into Mars’ atmosphere and also be removed from it. Credit: NASA Goddard Space Flight Centre / University of Michigan

Water-rock chemistry might have generated the methane, but scientists cannot rule out the possibility of biological origins. Methane previously had been detected in Mars’ atmosphere in large, unpredictable plumes. This new result shows that low levels of methane within Gale Crater repeatedly peak in warm, summer months and drop in the winter every year.

This is the first time we’ve seen something repeatable in the methane story, so it offers us a handle in understanding it. This is all possible because of Curiosity’s longevity. The long duration has allowed us to see the patterns in this seasonal ‘breathing.’

Chris Webster, co-author, Background levels of methane in Mars’ atmosphere show strong seasonal variations

In 2013, SAM detected organic molecules in rocks at the deepest point in the crater. These more recently findings, gathered further up the slopes of “Mount Sharp” add to the inventory of molecules detected in the ancient lake sediments. Thus, finding methane in the atmosphere and ancient carbon preserved on the surface gives scientists confidence that NASA’s Mars 2020 rover and ESA’s ExoMars rover will find even more organics, both on the surface and in the shallow subsurface.

NASA Successfully Transfers Sample

Following my last two Space Sunday updates concerning attempts to resume the collection of rock samples using Curiosity’s drilling mechanism, the US space agency has indicated a successful transfer of material gathered within the rover’s hollow drill bit into the rover’s on-board science suite (which includes the SAM instrument referred to above).

The new drilling capability is referred to as Feed Extended Drilling (FED), designed to bypass a formerly critical, but at risk of failure, piece of the rover’s drill system called the drill feed mechanism. This mechanism also used to form a part of the means by which samples used to be transferred from Curiosity’s arm-mounted turret to the on-board science suite. As it can no longer be used, engineers instead determined the sample could potentially be transferred to the science suite by positioning the drill bit directly over the sample intake ports and then running the drill in reverse, causing the gathered sample to (hopefully) trickle backwards and into one of the hoppers.

Referred to as Feed Extended Sample Transfer, the approach was tested on May 31st, 2018, and successfully saw the transfer of part of a sample obtained on May 19th into the hopper serving the rover’s Chemistry and Mineralogy (CheMin) unit.

Curiosity’s drill bit (upper right) positioned over one of the sample inlets on the rover’s deck leading to the on-board science suite. This image was captured on May 31st, 2018 (Sol 2068) by the rover’s Mast Camera (Mastcam). Credit: NASA / MSSS

The approach had already been successfully tested on Earth, but there were concerns the thin, dry atmosphere of Mars might not produce the same results. There’s also a matter of balance. Previously, any sample gathered by the drill would pass through the rover’s CHIMRA sieving system, which helps ensure the right amount is transferred to the on-board instruments. Without this, transfers become a matter of judgement, as engineer John Moorokian explained following the transfer:

On Mars we have to try to estimate visually whether this is working, just by looking at images of how much powder falls out. We’re talking about as little as half a baby aspirin worth of sample.

John Moorokian, lead developer of the FEST delivery method

The problem here is, were too little materials transferred, and CheMin and SAM would not be able to provide accurate analyses, but transfer too much of the unsorted material, and it could either clog instruments or remaining unused, potentially contaminating measurement of future samples. So far, it appears the first attempt has succeeded, although it will still be a while before the outcome of any analysis is known.
Continue reading “Space Sunday: of molecules, meteorites and missions”

Space Sunday: drills, neutrinos and a spaceplane

In May I wrote about an attempt to return the drill mechanism on the Mars Science Laboratory (MSL) rover Curiosity to operational status. As I noted in that report, use of the sample-gathering drill was suspended in December 2016, after problems were encountered with the drill feed mechanism – the motor used to extend the drill head leading to fears that continued use of the drill feed mechanism would see it fail completely, ending the use of the drill.

At the time of that report, a live test of the drill on Mars had just been carried out, but the results hadn’t been made public. However, on May 23rd, NASA issued an update confirming the test had been successful, and a sample of rock had been obtained.

The new drilling technique is called Feed Extended Drilling (FED). It keeps the drill head extended and uses the weight of the rover’s robot arm and turret to push the bit into a target rock. This is harder than it sounds, as it requires the weight of the rover’s arm to provide the necessary pressure to help push the drill bit into a rock – something it is not designed to do, and risks either breaking the drill bit or cause it to become stuck.

Engineers had spent more than a year developing the technique using Curiosity’s testbed “twin” on Earth before carrying out a preliminary test on Mars in February (see here), which was not intended to gather any sample. For the May 19th, 2018, test the mission team combined the FED approach to drilling with using the drill’s percussive mechanism with the intention of both testing the combined technique with an attempt to obtain a sample of rock.

The sample in question is of specific importance to the mission team, although it required a literal turnaround for the rover. For the last few months, Curiosity has been traversing “Vera Rubin Ridge” on “Mount Sharp”. In doing so, the rover passed a distinct rock formation mission scientists realised could fill a gap in their understanding about how “Mount Sharp” may have formed. However, at the time, there was no way to obtain a sample. Once it looked likely that drilling operations could be recovered, the decision was made in April to reverse the rover’s course and return to the rock formation, where the test was successfully carried out.

The team used tremendous ingenuity to devise a new drilling technique and implement it on another planet. Those are two vital inches of innovation from 60 million miles away. We’re thrilled that the result was so successful.

– Curiosity Deputy Project Manager Steve Lee.

The 5 cm (2-in) deep hole in a target called “Duluth”, captured by the rover’s Mastcam on May 20th, 2018 (Sol 2057) after a successful test allowed a rock sample to be gathered by the rover since October 2016. Credit: NASA/JPL / MSSS

The rover has since resumed its traverse towards an uphill area enriched in clay minerals that the science team is  also eager to explore. The next stage for the engineers it so figure out how to transfer the gathered sample ready for analysis by the rover’s on-board laboratory.

Previously, this would have involved passing the sample through another system on the rover’s “turret”, called CHIMRA (Collection and Handling for In-Situ Martian Rock Analysis). However, transfer into CHIMRA in part requires the use of the drill feed mechanism. As this can no longer be used in case it breaks. the idea – yet to be tested – is to try positioning the drill head over the hoppers feeding the science suite and then running the drill in reverse, allowing the sample  – held within the hollow drill bit – to trickle back out, and hopefully into the hoppers.

If It’s A Particle Jim, Then It’s Not As We Know Them

Neutrinos are elementary particles that interact only via the weak subatomic force and gravity. Their behaviour is explained by the Standard Model of particle physics.

In essence – and very broadly speaking – the Standard Model is a list of particles that go a long way toward explaining how matter and energy interact in the cosmos. Some of these particles – quarks and electrons, for example – are the building blocks of the atoms that make up everything we’ll ever touch with our hands. Others, like the three known neutrinos, are more abstract: high-energy particles which can be created naturally (within the core of stars or during supernova events, for example), or artificially (e.g. in nuclear reactors or nuclear explosions), and which stream through the universe, barely interacting with other matter. Billions upon billions of solar neutrinos pass through each of us every second without ever affecting us.

The LSND. Credit: Los Alamos National Laboratory

These neutrinos can be broken into three known “flavours”:  electron, muon and tau neutrinos. As waves of neutrinos stream through space, they periodically “oscillate,” jumping back and forth between one flavour of the three flavours and another – or that’s the theory.

In the 1990s, the Liquid Scintillator Neutrino Detector (LSND) at the Los Alamos National Laboratory, New Mexico, reported more neutrino detections than the Standard Model’s description of neutrino oscillation could explain, resulting in a new flavour of “heavy” neutrino being posited: the “sterile neutrino”.

At the time, the discovery met with excitement; physicists had long noticed a discrepancy between the predicted and actual number of anti-neutrinos, or the antimatter partners to neutrinos, produced in nuclear reactors. Sterile neutrinos could offer an explanation for the discrepancy. The only problem with the idea is that other than the LSND results, no-one has been able to find evidence for the existence of “sterile neutrinos”.

Until, possibly, now. A paper just published suggests that another neutrino detector – the MiniBooNE, operated Fermilab in Chicago – has also reported a similar result to LSND, resulting in the suggestion some neutrinos are oscillating into the “heavier” sterile neutrinos and then back into one of the recognised flavours. What’s more, combining the results of the MiniBooNE experiment with those of LSND suggests there is just a one-in-500 million chance of both results being a fluke.

Continue reading “Space Sunday: drills, neutrinos and a spaceplane”

Space Sunday: the Moonwalker and the artist

Astronaut and painter, Alan Bean in his Studio in Texas. Credit: unknown

The pool of men who flew to the Moon, and those who walked on its surface, as a part of NASA’s Apollo programme is sadly shrinking. And on Saturday May 26th, 2018, it became even smaller with the news that Alan Bean, the fourth man to set foot on the Moon had passed away.

His passing was unexpected. Although 86 years of age, he was in good health and was travelling with his family when he suddenly fell ill while in Indiana two weeks ago. He was taken to the Houston Methodist Hospital in Houston, Texas, to receive treatment, but passed away whilst at the hospital.

Born on March 15th, 1932 in Wheeler County, Texas, Alan LaVern Bean received a Bachelor of Science degree in Aeronautical Engineering from the University of Texas, Austin in 1955. While at the UT Austin, he accepted a commission as a U.S. Navy Ensign  in the university’s Naval Reserve Officers Training Corps and attended flight training.

Alan Bean in 1969 in a NASA publicity photograph ahead of the Apollo 12 mission. Credit: NASA

Qualifying as a pilot in 1956, he served four years  based in Florida flying attack aircraft. He was then posted to the U.S. Naval Test Pilot School (USNTPS) at Patuxent River, Maryland, where his instructor was the irrepressible Charles “Pete” Conrad. The two stuck up an enduring friendship which was to eventually take them to the Moon.

As a naval test pilot, Bean flew numerous aircraft prior to transferring back to fighter operations in 1962, again serving in Florida for a year. In 1963, he was accepted into NASA as a part of the Group 3 astronaut intake.

He had originally applied as a part of the Group 2 intake in 1962 alongside Conrad, but failed to make the cut. Coincidentally, Conrad’s Group 2 application  – which was successful – was also his second attempt to join NASA. He’d actually been part of the Group 1 intake, but  – always rebellious – he walked away for being subject to what he felt were demeaning and unnecessary medical and psychological tests.

Bean’s flight career at NASA was initially choppy: he was selected as a back-up astronaut with the Gemini programme but did not secure a flight seat. He then initially failed to gain an Apollo primary or back-up flight assignment. Instead he was assigned to the Apollo Applications Programme testing systems and facilities to be used in both lunar missions and training for flights to the Moon. In this capacity he was the first astronaut to use the original Weightless Environment Training Facility (WETF). This is a gigantic pool in which astronauts may perform tasks wearing suits designed to provide neutral buoyancy, simulating the microgravity they will experience during space flight. He became a champion for the use of the facility in astronaut training, which was used through until the 1980s, when is was superseded by the larger Neutral Buoyancy Laboratory (NBL) used in space station training.

On October 5th, 1967, Apollo 9 back-up Lunar Excursion Module (LEM) pilot Clifton Williams was tragically killed in an air accident. As a result, “Pete” Conrad, the back-up crew commander specifically requested Bean be promoted to the position of his LEM pilot. This placed the two of them, together with Command Module (CM) pilot Richard F. Gordon Jr on course to fly as the prime crew for Apollo 12, the second mission intended to land on the Moon.

Bean and Conrad approached their lunar mission with huge enthusiasm and commitment. In contrast to some of their comrades, who at times found the intense geological training the Apollo astronauts went through a little tiresome, they became extremely engaged in the training – which resulted in them gathering what Harrison Schmitt – the only true geologist to walk on the Moon thus far – later called, “a fantastic suite of lunar samples, a scientific gift that keeps on giving today.”

The Apollo 12 crew (l to r): Charles “Pete” Conrad, Commander; Richard F. Gordon Jr , Command Module pilot; and Alan Bean, Lunar Excursion Module pilot. Credit: NASA

In particular, Bean and Conrad became deeply involved in one of the primary aspects of their mission – a visit to the Surveyor 3 space craft.

The Surveyor programme was a series of seven robotic landers NASA sent to the Moon between June 1966 and January 1968, primarily to demonstrate the feasibility of soft landings on the Moon in advance of Apollo. Scientists were particularly keen that Conrad and Bean land close enough the probe so they could collect elements from it for analysis on Earth to see what exposure to the radiative environment around the Moon had treated them.

However, Bean had his own plans for the trip to the Surveyor vehicle: with Conrad, he conspired to smuggle self-timer for his Hasselblad camera in their equipment. The pair planned to secretly set-up the camera and use the timer to capture a photograph the pair of them standing side-by-side on the Moon – and confuse the mission control team as to how they had managed the feat! Unfortunately, Bean couldn’t locate the timer in their equipment tote bag until it was too late for the picture to be taken. Instead, he later immortalised the scene in his painting The Fabulous Photo We Never Took.

“The Fabulous Photo We Never Took” by Alan Bean. Courtesy of alanbean.com

Apollo 12 launched on schedule from Kennedy Space Centre on November 14th, 1969, during a rainstorm. Thirty-six-and-a-half seconds after lift-off, the vehicle triggered a lightning discharge through itself and down to the Earth through the Saturn’s ionized plume. Protective circuits on the Service Module falsely detected electrical overloads and took all three fuel cells off-line, along with much of the Command/Service Module (CSM) instrumentation.

A second strike then occurred 15.5 seconds later, resulting in further power supply problems, illuminating nearly every warning light on the control panel as it caused a massive instrumentation malfunction. In particular, the “8-ball” attitude indicator was knocked out and the telemetry feed to Mission Control became garbled. However, the vehicle continued to fly correctly, the lightning not having disrupted the Saturn V’s own instrumentation unit.

Left: Apollo 12 is struck by lightning, the discharge passing down the vehicle into its exhaust plume. Right: the launch complex tower is also struck by lightning after the departure of the Saturn V rocket. Credit; NASA

Continue reading “Space Sunday: the Moonwalker and the artist”

Space Sunday: drills, telescopes, pictures and doubts

In March I reported that NASA’s Mars Science Laboratory rover Curiosity had taken an important step in recovering its ability to drill into Martian rocks to collect samples. Now it looks like drilling operations could be resuming.

Use of the sample-gathering drill was suspended in December 2016, after problems were encountered with the drill feed mechanism – the motor used to extend the drill head between two “contact posts” designed to steady the rover’s turret during drilling operations. In particular, there was concern that continued use of the drill feed mechanism would see it fail completely, ending the use of the drill.

Since then, engineers have been trying to develop a means of using the drill without and reliance on the drill feed mechanism, and at the end of February 2018, a new technique was tested. Called Feed Extended Drilling, or FED,  it keeps the drill bit and head extended, and uses the weight of the rover’s robot arm and turret to push the bit into a target rock. This is harder than it sounds,as it requires the weight of the rover’s arm to provide the necessary pressure to help push the drill bit into a rock – something it is not designed to do, and might actually break the drill bit or cause it to become stuck. However, the rover passed the February test with flying colours.

This success meant that engineers could focus on recovering the drill’s percussive action. This assists in both helping the drill cut into a rock and in breaking the contact area under the bit up into a fine powder that can be collected by the collection tube surrounding the bit.

A close-up of the drill mechanism. In the centre is the hollow drill bit, which cuts into rock and gathers sample powder. The drum at the base of the drill is the first part of the sample collection mechanism. Also of this used to be extended up against a rock sample by the drill feed mechanism. Just visible cutting across the bottom right corner of the image is one of the two contact posts. The second post can be seen in part in the top right corner of the image. These are used to hold the rover’s robot arm steady against a target rock surface while the drill is extended for sample-gathering operations. Credit: NASA

On Saturday, May 19th, and following further tests using Curiosity’s Earth-base test bed twin, the command was sent to Mars for Curiosity to carry out a second drilling test using both the FED approach and with the drill percussive action enabled. Unlike the February test, however, this one has an additional goal: to actually recover a special sample of rock.

For the last couple of months, the rover has been making its way along a feature on “Mount Sharp” dubbed “Vera Rubin Ridge”, toward an uphill area enriched in clay minerals that the science team is eager to explore. In doing so, the rover passed a distinct rock formation that could fill a gap in the science team’s knowledge about Mount Sharp and its formation.

Testing the FED / percussion approach to drilling on Earth using Curiosity’s test-bed “twin”. Not how the drill head (centre) is fully extended, so the contact posts cannot be used. Forward pressure on the drill is being provided entirely by the rover’s robot arm. Credit: NASA/JPL

Given the progress made in trying to get the drill working again, the decision was made to reverse Curiosity’s course in mid-April and drive back to the rock formation in the hope that the May 19th test could gather a sample from it. Commenting on the decision, Curiosity principal scientist Ashwin Vasavada  said, “Every layer of Mount Sharp reveals a chapter in Mars’ history. Without the drill, our first pass through this layer was like skimming the chapter. Now we get a chance to read it in detail.”

If the new technique has allowed Curiosity to gather a sample – at the time of writing this article, NASA had yet to provide an update on the operation – the engineering team will immediately begin testing a new process for delivering that sample to the rover’s internal laboratories. This is again a complex process, which in the past has involved the drill feed mechanism to transfer material gathered by the drill to another mechanism called CHIMRA (Collection and Handling for In-Situ Martian Rock Analysis), also mounted on the rover’s turret. CHIMRA sieves and sorts the material, grading it by size and coarseness before transferring it to the rover’s science suite, located in Curiosity’s main body.

Curiosity’s “fingers”: the five instruments on the rover’s turret, including the drill with the feed mechanism motors behind it and the two angled contact posts clearly visible, and the CHIMRA system used for sieving and sorting sample material gathered by both its own scoop (for surface material) and the drill (for rock samples). Credit: NASA 

Success with both the drilling operation and same transfer will mean – allowing for fine-tuning and other adjustments – the drill could be re-entering regular use in the near future.

Continue reading “Space Sunday: drills, telescopes, pictures and doubts”

Space Sunday: Flying on Mars, working on the Moon and visiting Europa

The Mars helicopter demonstrator: set to fly with the Mars 2020 rover mission. Credit: NASA

In November 2015 I wrote about an idea to fly a robotic drone helicopter on Mars as a part of the next rover mission, currently referred to as the Mars 2020 mission. On May 11th, 2018, NASA confirmed that Mars 2020 will now include the drone, to be carried by the rover as a technology demonstrator.

The unit, under development since 2013, is quite small; the body is the size of a box of tissues, and the contra-rotating rotor blades have a diameter of a metre (39 inches). Weighing some 1.8 kg (4.4 lbs), the drone will be battery-powered, using solar cells to recharge the batteries, which will also power a dedicated heating source to help it survive the cold Martian nights.

The drone will be carried underneath the rover, which will used the same “skycrane” landing mechanism as the Mars Science Laboratory (MSL) rover Curiosity. Once a suitable location for its deployment is found, the rover will lower it to the ground and move away to let the drone commence its first flight.

An artist’s impression of the key elements in the Mars Helicopter. Credit: NASA

Up to five flights are planned over a 30-day test campaign. The first will be very short-duration, enough to allow the helicopter to ascend to around 3 metres (9 feet) and hover for 30 seconds while the flight systems are checked out. Later flights will last up to 90 seconds and travel as far as a few hundred metres before landing to allow the solar panels to recharge the battery system.

Flying any sort of aircraft on Mars is a significant challenge. For example, the atmosphere of Mars is only one percent that of Earth, or the equivalent of being 30 km (100,000 feet) above the surface of the Earth – more the double the altitude any helicopter has been able to fly. This means the drone has to be both very lightweight and extremely powerful for its size if it is to get airborne on Mars.

To make it fly at that low atmospheric density, we had to scrutinize everything, make it as light as possible while being as strong and as powerful as it can possibly be.

– Mimi Aung, Mars Helicopter project manager

To achieve lift, The helicopter’s blades will rotate at up to 3,000 revolutions per minute, 10 times the rate of a terrestrial helicopter. The vehicle is also entirely autonomous – the time delay in Earth-Mars-Earth communications means that conventional drone flight under human control is impossible.

Mimi Aung, Mars Helicopter project manager. Credit: NASA

Instead, flight parameters will be uploaded to the Mars 2020 rover for relay to the helicopter, which will also be able to receive and act on additional instructions sent by the rover so that it doesn’t have to carry the entire flight plan within its own computer.

NASA sees Mars Helicopter as demonstrating how aerial vehicles might serve as scouts for future missions to Mars. This idea is explored in the most recent video promoting the mission, with a helicopter scanning and image the terrain around a rover.

The ability to see clearly what lies beyond the next hill is crucial for future explorers. With the added dimension of a bird’s-eye view from a ‘marscopter,’ we can only imagine what future missions will achieve.

– Thomas Zurbuchen, NASA associate administrator for science

As a technology demonstrator,the Mars Helicopter is seen as a high-rick project, although NASA has been keen to stress that if the helicopter fails for any reason, it will not impact the overall Mars 2020 mission. Nevertheless, the news the project will be carried on the rover mission hasn’t been positively received in all quarters – including within the Mars 2020 mission itself.

I am not an advocate for the helicopter, and I don’t believe the Mars 2020 project has been an advocate for the helicopter.

– Ken Farley, project scientist for Mars 2020

The concern among the rover science team is that the helicopter’s planned 90-day test campaign will prove to be a disruption in the rover’s overall science mission. However, Farley also indicated that the rover team are working to integrate the helicopter into the rover’s mission and accommodate its requirements.

Continue reading “Space Sunday: Flying on Mars, working on the Moon and visiting Europa”