Tag Archives: MSL

J’arrive: a new chapter begins

CuriosityOn Thursday September 11th, a special teleconference was held by the NASA Jet Propulsion  Laboratory to discuss the status of the Mars Science Laboratory and the Curiosity rover.

The conference featured Jim Green, director, Planetary Science Division, NASA Headquarters, Washington, John Grotzinger, Curiosity project scientist, California Institute of Technology, Pasadena and Kathryn Stack, Curiosity Rover mission scientist, NASA’s Jet Propulsion Laboratory, Pasadena. California, and marked the first direct conference on the mission hosted by JPL since the start of the year.

The focal point for the briefing was to announce that just over two years since its arrival on Mars, having covered a distance of some 6 kilometres and having already fulfilled its primary mission objective – to locate a region on Mars which shows both chemical and geological indications that it may once have been amenable to development and support of microbial life – the rover had, again in geological terms, arrived at its primary exploratory target: Aeolis Mons, which NASA refers to as “Mount Sharp”.

Curiosity still has around two kilometres left to drive before it can be said to be actually “on” or climbing Mount Sharp, but the changes in geology and terrain which it is now encountering are sufficiently clear for the science team to state the rover is effectively traversing the “boundary” between the floor of Gale Crater and the slopes of Aeolis Mons itself.

Originally, it had been intended to drive the rover further south from its current location near an uprising dubbed the “Pahrump Hills” – originally seen as a potential target site for further sample drilling – to a series of low buttes named after the late co-founder of The Planetary Society, Bruce Murray. From orbit, this had been seen as the best route by which the rover could skirt an extended line of sand dunes lying between it and “Mount Sharp” and commence a climb up onto the lower slopes.

However, further examination of the terrain adjacent to the Pahrump Hills / Zabriskie Plateau has revealed it to be softer than the terrain than the rover has been crossing, and potentially more suited to driving onto the slopes of the mound. Dubbed the “Murray Formation”, this terrain also forms a visible boundary between the Mount Rainer-sized mound of “Mount Sharp” and the crater floor sediments, and so offers the potential for further science discoveries. Thus, from a driving characteristics point of view and a science perspective, it offers a shorter, more interesting route onto the mountain proper.

The view from “Amargosa Valley”: a mosaic of images capture by Curiosity’s Mastcam showing the “Pahrump Hills” (centre of the image, just above the scale bar), above which sits the Murray Formation and the revised route up onto the lower slopes of Mount Sharp (click any image for full size)

As well as being geologically different to the sediments of the crater floor, the Murray Formation is topographically different as well, which is driving a lot of interest in the science team in terms of what it might indicate about the way in which “Mount Sharp” was formed. The floor of Gale Crater – more correctly known as Aeolis Palus – bear the marks of considerable cratering which can be seen from orbit. However, the layers of the Murray Formation – essentially a scarp between the crater floor and Aeolis Mons – have almost no visible cratering at all.

The topological differences between the plains of Gale Crater and the slopes of Mount Sharp can be seen in this false colour image. Note the rich cratering evident across the sedimentary basin of Gale Crater and the almost complete absence of cratering along the Murray Formation.

During the course of the next few weeks, the rover will pass over / around Pahrump Hills, hopefully gathering a suitable rock sample using the “compressed drilling” routine,. Then it will turn more sharply southwards than originally planned, travelling directly onto the Murray Formation, rather than continuing in a more south-westerly direction to Murray Buttes before turning onto the slopes of the formation. The rover will still study the area of the Murray Buttes, but will now do so at their eastern extremes, allowing the science team to also investigate some nearby sand dunes.

While “Bonanza King” proved to be unsuitable for drilling for an actual sample for analysis, it did provide sufficient data to help the team in determining a revised science programme, and in their decision to traverse the Murray Formation and onto “Mount Sharp” proper sooner rather than later. This is because spectral analysis for the rock revealed it to have very high silica content (the only location on Mars so far studied with similar levels of silica is half a world way and was studied by the Spirit MER), which stands a marked contrast to rock samples so far gathered by the rover.

The interior of “Bonanza King”, seen here following the “mini drill” test to assess its suitability for sample drilling, showed intriguing promise. Sadly, the rock moved too much during the test drilling to be deemed safe for sample gathering. Evidence of the movement can be seen in the way the light-coloured tailing have unevenly flowed away from the drill cut, rather than circling it

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You can’t always get what you want …

CuriosityAugust 5th marked the 2nd anniversary on Curiosity’s landing on Mars. The “landiversary”, as NASA dubbed the occasion, passed in something of a subdued manner in many respects, featuring a re-run of the August 2012 video reviewing the MSL’s arrival on Mars. Reviews of the mission from the perspective of two years on from that remarkable lading didn’t start-up until the days after the anniversary, with videos and lectures from members of the mission team.

One of the films which did appear, directly out of Caltech, rather than NASA’s Jet Propulsion Laboratory (which is located on Caltech’s Pasadena, California, campus), is Our Curiosity, a 6-minute celebration of Curiosity’s mission, and humanity’s drive to explore, to seek, to learn, and to understand, narrated by Felicia Day and the superb Neil DeGrasse Tyson.

August 5th also marked my last MSL report, when Curiosity was some 3 kilometres from the lower slopes of “Mount Sharp”, the huge mound at the centre of Gale Crater, and the rover’s primary target for exploration. At that time, the rover had started to cross a region of chaotic terrain, marked by a rocky plateau cut by a series of sandy-bottomed valleys. The plateau itself proved to be littered with sharp-edges rocks and stones which had already caused some increase in the wear and tear being suffered by the rover’s wheels – albeit not as much as mission engineers had feared – by the time Curiosity had reached the edge of the nearest of the shallow valleys, which had been dubbed “Hidden Valley”.

The plan had been to use the valleys, where the sand would be less wearing on the rover’s aluminium wheels, to reach an exposed area of bedrook designated the “Pahrump Hills”, where Curiosity would engage in further rock sampling work prior to it continuing on to the “Murray Buttes”, the entry point for its ascent up the lower slopes of “Mount Sharp”.

However, rather than drive the one-tonne rover straight through the middle of the valley, where there are numerous dunes of potentially soft, wind-blown sand which might cause some difficulty traversing, the idea had been for Curiosity to skirt along the edge of the valley, where it was hoped the sand would be firmer and make for a better driving surface. Unfortunately, this proved not to be the case; as the rover proceeded along “Hidden Valley” it exhibited far more signs of wheel slippage than had been anticipated, giving rise to fears that it might get bogged-down in the sand were it to continue.

The sands of Mars: an image from Curiosity’s black and white Navcam system captured on August 4th, showing the loose sands the rover was traversing as it continued into “Hidden Valley” (click for full size)

As a result, the rover reversed course, driving back out of the valley. In doing so, it crossed the rocky “ramp” it had used to originally enter the valley, and one of its wheels cracked the slab-like rock’s surface, revealing bright material within, possibly from mineral veins. The rock, dubbed “Bonanza King” showed similar signs of origin as “Pahrump Hills”, so a decision was made to examine it as a possible substitute drilling site.

“Geologically speaking, we can tie the Bonanza King rocks to those at “Pahrump Hills”. Studying them here will give us a head start in understanding how they fit into the bigger picture of Gale Crater and Mount Sharp,” said Curiosity Deputy Project Scientist Ashwin Vasavada, before continuing, “This rock has an appearance quite different from the sandstones we’ve been driving through for several months. The landscape is changing, and that’s worth checking out.”

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Two years on: target in sight

CuriosityAugust 5th 2014 marked the second anniversary of Curiosity’s remarkable arrival on Mars, in what was dubbed by members of the mission team as the “seven minutes of terror”.

It was one of the most anticipated touch-downs of a remote vehicle on another planet in history, and was followed minute-by-minute the world over via the Internet, with people watching NASA TV, following events on Twitter and even witnessing them in “real-time” through the unique focus of NASA’s Eyes on the Solar System simulator website (you can still replay the landing on the simulator).

Since then, Curiosity has done much, including meeting its primary science goal to find evidence of environments which may once have been suitable for the nurturing of microbial life (Curiosity isn’t able to detect any evidence of microbial life, past or present itself as it has no direct means to identify organic compounds or minerals, that will be the role of the next rover mission, scheduled for 2020 – see later in this article).

Most recently, the rover has been approaching its main exploratory goal, the large mound at the centre of Gale Crater which has been dubbed “Mount Sharp” by NASA, having been “on the road” for almost a year, driving steadily south, with the occasional stop-over at various scientific points of interest.

Since my last MSL update, Curiosity has achieved another mission mile stone and another mission first. On June 27th, the day of my last update, the rover trundled over the boundary line of its 3-sigma landing ellipse. Then on July 12th, it captured new images of its onboard laser firing.

As to the first of these events, I’ll let Guy Webster of NASA’s Jet Propulsion Laboratory explain.

“You must be wondering, ‘What the heck is a 3-sigma landing ellipse?’ It is a statistical prediction made prior to landing to determine how far from a targeted centre point the rover might land, given uncertainties such as the atmospheric conditions on landing day. The ‘3-sigma’ part means three standard deviations, so the rover was very, very likely (to about the 99.9-percent level) to land somewhere inside this ellipse. Such 3-sigma ellipses get a lot of scrutiny during landing-site selection because we don’t want anything dangerous for a landing – such as boulders of cliffs – inside the ellipse.”

In Curiosity’s case, the 3-sigma ellipse marked a relatively flat area on the floor of Gale Crater some 7 x 20 kilometres (4 x 12 miles) in size which was as close to the slopes of “Mount Sharp” as mission planners dare to bring the rover in for landing without risking it coming down in either chaotic terrain or on a slope where it might slide or topple over as the Skycrane set it down. The landing zone was also relatively close to the areas of geological interest which became known as “Glenelg” and “Yellowknife Bay”, and which the rover spent a good part of a year exploring – achieving its primary science goal in the process.

The Mars Reconnaissance Orbiter was overhead at the time the rover crossed this imaginary line in the sands of Mars, and captured the moment using its High Resolution Imaging Science Experiment (HiRISE) camera.

Caught in its tracks: NASA’s Mars Reconnaissance Orbiter photographs Curiosity as the rover crosses the boundary (marked by the blue line) of its original landing ellipse (click any image in this article for full size)

Sol 687 (July 12th, 2014 PDT) was the day on which the rover captured images of its laser firing on a rock dubbed “Nova”.

The laser, which is a part of the ChemCam system on mounted on the rover’s mast, is used to vaporise minute amounts of material on target rocks. Light from the resultant plasma is captured by ChemCam’s telescope for spectrographic analysis.

In all, the laser has been fired over 150,000 times in the two years since Curiosity arrived on Mars, and the results of firings have been seen in many “before and after” shots of rocks on the receiving end of a laser burst. What made this event special was that the burst firing at “Nova” was captured by the rover’s turret-mounted Mars Hand Lens Imager (MAHLI). This allowed NASA to produce a film showing the moment of impact of the laser shots.

In the first part of the film, the initial “spark” of a single laser pulse can be seen striking the surface of “Nova”. This is followed by an enhanced set of images showing the laser firing at 10 times a second, disrupting dust and minerals on the rock as the plasma cloud erupts.

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687 days on

CuriosityMonday June 23rd was notable in two worlds as a special occasion.

For the virtual world of Second Life, it marked the 11th anniversary of opening the doors to the public. On Mars, it marked the completion of Curiosity’s first Martian year on the planet (687 days).

To mark the event, NASA released a “selfie” of the rover as it sat next to a rock called “Windjana”, which was the site of the rover’s third drilling / sample gathering operation, in the region dubbed “The Kimberley”.

The images used in the picture were captured using the Mars Hand Lens Imager (MAHLI), located on the turret mounted on the rover’s robot arm, were captured on 613th Martian day, or Sol, of Curiosity’s work on Mars (April 27th, 2014, PDT) and Sol 627 (May 12th, 2014, PDT). Combined, they show the rover in a parked configuration together with the sample gathering hole cut into “Windjana”, the drilling operation having taken place on Sol 621 (Monday May 5th, 2014, PDT).

Curiosity's selfie: all of the rover except the robot arm is visible in this composite image made up of shots taken before and after the "Windjana" sample drilling - the hole from which is visible, lower left

Curiosity’s selfie: all of the rover except the robot arm is visible in this composite image made up of shots taken before and after the “Windjana” sample drilling – the hole from which is visible, lower left

Since that time, the rover has resumed the drive down towards “Murray Buttes”, the point where it is hoped Curiosity will be able to bypass a line of sand dunes and make its way onto the lower slopes of “Mount Sharp”, more properly called Aeolis Mons, the large mound occupying the central area of Gale Crater and the missions’ primary target for investigation.

Curiosity is now over half-way to “Murray Buttes”, with no further major waypoints to be examined on the route. however, due to the wear-and-tear on the rover’s wheels while traversing a part of “The Kimberley” and “Cooperstown” before it, the route southwards has been revised somewhat to offer smoother driving terrain for the rover.

The added wear-and-tear of the wheel first became something of a concern in February of this year, and later prompted a revision to in the planned route to reach the desired waypoint at “The Kimberley” and also in the rover driving team perfecting new techniques for driving the rover – such as by taking it backwards over some terrain.

The (Martian) year to date: from Bradbury Landing in august 2012, through “Glenelg” and “Yellowknife Bay” and onwards to “The Kimberley”, Curiosity’s travels in Gale Crater and, in white, the planned route to “Murray Buttes”.

Following its departure from “The Kimberley” on Sol 630 (May 15th, 2014, PDT), the rover drove almost continuously for a month, covering a further 1.2 kilometres 0.75 miles), and is still continuing onwards.

Although Curiosity’s route will carry it past the majority of the sand dunes between it and “Mount Sharp”, it will have to traverse an area of sand in order to reach its major target. To help with this, the rover’s Earthbound “stunt double”, dubbed the Scarecrow, was taken out to the Dumont Dunes in California’s Mojave Desert, near Death Valley, where it was put through a series of test drives over real and artificially constructed sand dunes and various terrains. This allowed engineers to examine the rover’s behaviour over softer terrain types, enabling them to better understand how the rover might react when encountering similar surfaces on Mars.

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