Category: Space Sunday

Curiosity, the Mars Science Laboratory rover, resumed operations on Mars resumed operations on March 11th 2015, after an electrical short circuit in the rover’s robot arm caused a suspension of activities while the matter was investigated, and short itself having triggered the rover to switch to a “safe” mode to prevent any potential damage.

The short, was not enough to damage the rover’s electrical systems in any way, occurred occurred when the was attempting to transfer samples of material gathered from a rock dubbed “Telegraph Peak” from the drill head to the CHIMRA system by subjecting the entire turret to rapid vibrations from the drills percussion action. Extensive tests were carried out over 10 days to try to determine if the short was transient, or indicative of a potential fault. Only one test during this time caused a further short, which lasted around 1/100th of the second, and didn’t interrupt the drill motor.

The results of the tests gave engineers a high degree of confidence that the short wasn’t indicative of the major fault developing, and so operations recommenced on March 11th with the transfer of some of the “Telegraph Peak” material being delivered to the rover’s on-board laboratory while analysis of the results from the tests carried out on the drill mechanism continue to be examined.

As Curiosity now heads on up the slopes of “Mount Sharp”, aiming to pass through a shallow valley dubbed “Artist’s Drive”, NASA  has confirmed that the rover has found “biologically useful nitrogen” on Mars.

Nitrogen is essential for all known forms of life, since it is used in the building blocks of larger molecules like DNA and RNA, which encode the genetic instructions for life, and proteins, which are used to build structures like hair and nails, and to speed up or regulate chemical reactions. On Earth and Mars, however, atmospheric nitrogen is locked up as nitrogen gas (N2) – two atoms of nitrogen bound together so strongly that they do not react easily with other molecules; they have to become “fixed” (separated) in order to participate in the chemical reactions needed for life.

On Earth, certain organisms are capable of fixing atmospheric nitrogen and this process is critical for metabolic activity. However, smaller amounts of nitrogen can also be fixed by energetic events like lightning strikes.

While Nitrogen has long been known to exist on Mars, a study by the NASA team supporting the Sample Analysis at Mars (SAM) experiment onboard the rover reveals that NO3, a nitrogen atom bound to three oxygen atoms and a source of “fixed” nuitrogen  has been found in numerous samples gathered by the rover during its journey across Gale Crater.

Although the report’s authors make it clear that there is no evidence to suggest that the fixed nitrogen molecules they’ve discovered were created by life. The confirmation that NO3 does exist adds significant weight to the potential for Mars once having the kind of environment and building blocks needed by life. This is particularly relevant, given that one of the areas in which the NO3 was identified is the “Yellowknife Bay” area, which Curiosity examined in early 2013, and which was shown to have once had a very benign environment for life processes, complete with water, many of the right chemicals, and a local source of energy. This prompted Jennifer Stern of NASA’s Goddard Space Flight Centre in Greenbelt, Maryland, and a co-author f the report to note, “Had life been there, it would have been able to use this nitrogen.”

However, it is more likely that the fixed nitrogen that has been discovered may have been generated primarily by the numerous powerful impacts that occurred about 4 billion years ago, during a period known as the Late Heavy Bombardment, when the inner planets of the solar system were “hoovering up” the remaining debris of asteroids and rock scattered across their orbits.  That said, “fixed” nitrogen has also been detected high in the modern day Martian atmosphere by Europe’s Mars Express.  What’s missing at the moment is the capability to get a big enough nitrate signal for any nitrogen isotope data which might exist, as none of the experiments on Mars are broad enough to do so, thus this is likely to be something future missions to Mars will consider.

Continue reading “Space Sunday: nitrogen nibbles” →

Following my last Curiosity update, which noted that other than for one potential drilling / sampling target, work was wrapping-up for the Mars Science Laboratory in the “Pahrump Hills” location on the lower slopes of “Mount Sharp”, the decision was taken to indeed gather one more sample.

The selected target had been dubbed “Telegraph Peak”, and sits towards the top end of “Pahrump Hills”. It was selected because Alpha Particle X-ray Spectrometer (APXS) measurements carried out by the rover during its 5-month “walkabout” in “Pahrump Hills” revealed the rocks in the area to be relatively enriched in silicon when compared to the corresponding amounts of aluminium and magnesium, which is somewhat different to rocks sample prior to the rover arrival at the basal slops of “Mount Sharp”. This enrichment has also shown to increase the further up the slopes of “Pahrump Hills” the rover climbed, which is of interest to the science team.

“When you graph the ratios of silica to magnesium and silica to aluminium, ‘Telegraph Peak’ is toward the end of the range we’ve seen,” Curiosity co-investigator Doug Ming explains. “It’s what you would expect if there has been some acidic leaching. We want to see what minerals are present where we found this chemistry.”

Sampling took place on February 24th, 2015 (PDT) or Sol 908 for the rover on Mars. For the first time in Curiosity’s time on Mars, it was carried out with no preliminary “mini-drill” operation. Instead, the science team judged that analysis of the rock by APXS indicted it was of a very similar nature to the previous two sample drilling sites in “Pahrump Hills”, and the new lower percussion drilling capabilities the rover now has were judged as sufficiently safe enough to go ahead with a direct sample gathering operation.

As I’ve covered previously in these pages, obtaining a sample for analysis is a multi-part operation. First the rock is drilled, and a core sample forced up through the drill bit into a one of two sample collection chambers at the top of the drill mechanism. From here, the sample is “shaken” through a feed to another device in the rover’s robot arm turret called CHIMRA – the Collection and Handling for In-Situ Martian Rock Analysis system, used to separate the tailings through a series of sieves, ready for different sizes of sample grains to be passed through the the rover’s on-board laboratory systems.

Both of these operations require the use of the drill’s percussive system to vibrate the turret, forcing material both from the drill’s sample collection chamber and through CHIMRA. However, on February 27th, during the initial operation to move the sample tailings from the drill chamber to CHIMRA, Curiosity’s on-board fault protect system identified a transient short circuit within the robot arm’s electronics. The immediately resulted in all arm-related activities being shut down, and the arm and turret locked into position ready for diagnostic operations to commence.

A transient short can occur for a number of reasons, and can pass without significant problems. However, it may also indicate a potential issue which might require some measure of action, such as a change in operating procedures or a restriction on how a mechanism is used, in order to avoid the issue becoming a serious problem in the future. To this end, following the fault report, mission engineers started diagnosing the problem, with almost all rover operations halted while they did so.

On Thursday, March 5th, as a part of the investigative process, the rover was commanded to carry out a series of vibration tests of the kind performed while forcing the transfer of samples from the drill to CHIMRA. The vibrations were carried out with the robot arm and turret in the same orientation and position which caused the initial triggering of the fault protection system, and in the third of 180 repeat motions, a similar transient short occurred, lasting less than one one-hundredth of a second, enough to trigger the rover’s fault protection systems, and confirming there does appear to be some kind of electrical issue.

Tests are now under-way to determine whether or not the short will occur with the turret in different orientations, and may be followed by additional tests to see if it occurs with the arm in different positions. If no shorting occurs with either a change in the orientation or position of the turret / arm, then the most obvious step in preventing any recurrence of the issue is to avoid placing the turret / arm in the same orientation for sample transfer operations during future drilling activities.

It is hoped that the tests can be completed in the course of the next week. If they show that operations can be resumed safely, it is anticipated that the sample transfer operations will be completed, and Curiosity will then be ready to resume its climb up “Mount Sharp”, leaving “Pahrump Hills” via a narrow valley the science team have dubbed “Artist’s Drive”.

Continue reading “Short circuits on Mars and mapping asteroids” →

Curiosity, NASA’s Mars Science Laboratory (MSL), has been wrapping things up in the “Pahrump Hills” region at the base of “Mount Sharp”, the mountain-sized mound of deposited material occupying the centre of Gale Crater.

For the last several months, the rover has been engaged on what geologists on Earth call a “walkabout”, zigzagging back and forth across the area, looking for targets of interest for follow-up investigations, and allow the science team to better understand the geology and form of the region.

This method of activity is a change from how Curiosity has largely operated to date, which has seen the rover primarily move from point-to-point along its route, only re-visiting sites as a part of its onward movement towards the goal of reaching and climbing “Mount Sharp” (such as when travelling into, and then back out of the “Glenelg” and “Yellowknife Bay” regions Curiosity first explored in 2012 / 2013).

In this respect, and as Aileen Yingst, the Deputy Principal Investigator with the Mars Hand Lens Imager (MAHLI) on the rover, describes, Curiosity has been demonstrating just how much of an avatar it is for the science team, allowing them to careful investigate, examine and catalogue “Pahrump Hills” in a rich, practical way using the very human technique of the “walkabout”, which will serve the mission well as the ascent up “Mount Sharp” continues.

Most recently, and since collecting samples from “Mojave 2″, the area of rock displaying interesting crystalline elements within it, Curiosity has been looking at an area geologists dubbed “pink cliffs”, which shows further signs of the crystalline structures, and might be a candidate for further investigation. If so, it will be the last stopping point in “Pahrump Hills” before Curiosity continues its climb up “Mount Sharp”.

Oppy Reaches 11

January 25th, 2015 saw NASA’s Mars Exploration Rover, Opportunity, reach it’s eleventh anniversary on Mars. The rover, one of two MER vehicles, arrived on Mars at January 25th, 2004 (Universal Time), ready to start a mission initially planned to last just 90 days.

Since then, and up to its anniversary, “Oppy” has travelled a distance of some 41.7 kilometres (25.9 miles). While this doesn’t sound that much (and in truth, a human science team could have travelled that far in just a few days, including time for any science carried out along the way), remember that “Oppy’s” forward speed is measured in centimetres per hour.

As one of two solar-powered MER rovers (the second, Spirit having finally succumbed to the hostile environment on Mars around March 215th, 2011), Opportunity has carried out an incredible amount of work, and greatly contributed to our understanding of the planet, returning compelling evidence about wet environments on ancient Mars.

The rover marked its anniversary by reaching the summit of “Cape Tribulation”, an uprising close to the rim of 20 kilometre (13.7 mile) wide Endeavour Crater, which the rover has been gradually circumnavigating. This involved a change in elevation for “Oppy” of about 135 metres (440 feet), and afforded it a panoramic view of the crater and the land around it, presenting a unique opportunity for geological observations of the crater and its rim.

 A New Mars Mystery

That night, too, there was another jetting out of gas from the distant planet. I saw it … That night another invisible missile started on its way to the earth from Mars, just a second or so under twenty-four hours after the first one.

– The narrator, H.G. Wells’ The War of the Worlds

Okay, so it’s unlikely to be the sign of an impending invasion of Martians possibly ticked-of at the way we’re cluttering-up their planet with our probes and landers and rovers, but recent events high in the atmosphere of Mars have given rise to some excitement.

The images, originally capture in 2012, show huge plumes rising some 250 kilometres (156 miles) into the most tenuous reaches of Mars’ thin atmosphere.

The plumes occurred on two separate occasions in March and April 2012, and were spotted by amateur astronomers. Each time, they developed with relative rapidity, rising upwards and outwards to cover areas of some 1000 x 500 kilometres (625 x 312.5 miles) in a period of around 10 hours before remaining visible for up to 10 days at a time, their structure and form changing on a daily basis.

Unfortunately, neither event was seen from orbit about Mars, occurring so high on the planet’s limb as to be effectively out-of-sight for the NASA and ESA orbital vehicles, and by the time word had spread sufficiently about the observations, the events were largely over.

However, investigations into images of the planet taken by the Hubble Space Telescope in orbit around the Earth have revealed similar plumes being imaged in the past. However, with the exception of an image captured in 1997, none have been anywhere near as high or dramatic as the 2012 events.

So what might have caused this plumes to occur? The answer to that question is uncertain.

Continue reading “Avatars on Mars, Falcons in Florida and oceans in space” →

NASA’s Curiosity rover has been a busy bunny on Mars. Currently still parked in the “Pahrump Hills” terrain on the lower slopes of “Mount Sharp”, the Mars Science Laboratory (MSL) rover has now completed its latest drilling activity, collecting samples from a rock dubbed “Mojave 2”.

This isn’t actually the rock from which the science team had originally hoped to gather samples. That rock, dubbed “Mojave” broke apart as a result of the percussive action of the rover’s drill during a “mini-drill” test. As a result, the rock was ruled out as a sample gathering target. “Mojave” was of particularly interest to scientists as Curiosity had images tiny, rice-grain sized crystalline minerals that might have resulted from evaporation of a drying lake, thus presenting the science team with a further insight into environmental conditions within Gale Crater.

To counter this loss, the team relocated Curiosity to  “Mojave 2”, another rock within the same outcrop as “Mojave”, and which exhibits similar crystalline features. In doing so, the team were able to bring into play software improvements only recently uploaded to the rover as a part of an overall systems upgrade, which was deployed to one of the rover’s two computer systems at the end of January.

The software improvements for the drill are the result of investigations into the fracturing of a rock during a previous attempt to obtain samples prior to the rover arriving on “Mount Sharp”. Like an Earth-based hammer drill, the rover’s drill uses a percussive action, so that as well as drilling into a rock, the drill bit effectively hammers its way into the rock. In all, there are six settings governing the amount of percussive energy used during drilling, which range from a gentle tapping (level 1) through to hammering at the rate of 30 times a second with a 20-fold increase in energy imparted (level 6).

During early drilling operations the software monitoring these percussion settings “learned” that defaulting to the “level 4” setting best met the needs of gathering samples in the harder rock types the rover initially encountered. However, this was proving too forceful for the softer rocks closer to, and on, “Mount Sharp”, but the software was unable to switch down to a lower setting.

The new update causes the drill software to reset to “level 1” after each drilling operation, and then step through the levels incrementally until the ideal is found. As a result, a sample was gathered from “Mojave 2” without the drill needing to step beyond the “level 2” percussion action.

Drilling operations on “Mojave 2” took place on Sol 881 and Sol 882 (January 28th and 29th, PDT, respectively). As per standard operating procedure, the first drilling operation was a test “mini drilling” to see how the rock responded to encroachment and cutting. The second, which took the dill to a depth of around 6.5 centimetres (2.6 inches). The gathered samples were then sifted and sorted through the CHIMRA system in the rover’s turret, prior to being transferred via the surface scoop to Curiosity’s primary laboratory systems, ChemMin and SAM.

At the same time as Curiosity was carrying out its initial analysis of the “Mojave 2” rock, NASA released an image captured by the HiRise (High Resolution Imaging Science Experiment) carried aboard the orbiting Mars Reconnaissance Orbiter (MRO), which forms the mainstay of the rover’s communications with Earth. The image, which was taken on December 13th, 2014, reveals Curiosity mid-way through its “walkabouts” in “Pahrump Hills”, when it was seeking potential targets of interest for further study.

While not the first time the rover has been imaged from orbit, this is one of the clearest pictures from the rover yet capture from an altitude of around 280 kilometres (175 miles) above the surface of Mars.

Initial results from ChemMin (the Chemical and Mineralogy) instrumental has shown that the rock was likely effected by water that was much more acidic in nature than evidenced through the analysis of other rock samples obtained by the rover. The still-partial analysis shows a significant amount of jarosite, an oxidized mineral containing iron and sulphur that forms in acidic environments. This raises the question of whether the more acidic water was part of environmental conditions when sediments were being deposited to form “Mount Sharp”, or the result of fluids soaking the rocks at a later time.

ChemMin was also unable to identify a clear candidate mineral for the crystalline deposits which first attracted the science team to the outcrop; this presents the possibility that the minerals responsible for originally forming the crystals may have been leached away over time and replaced by other minerals during later periods of wet environmental conditions.

It is hoped that SAM – the Sample Analysis at Mars – suite of instruments may be able to reveal more about the nature and composition of the samples once they have completed their round of analysis. Depending on the outcome of this work, Curiosity may be ordered to gather a further rock sample from “Pahrump Hills”, or may be ordered to continue upwards and into new territory on “Mount Sharp”.

Continue reading ““I spy with my big eye…” and landing a rocket on Earth” →