Category: Other Worlds and Tech

On the 5th/6th August 2012, an aerodynamic capsule large enough to hold compact family car separated from its cruise stage “life support” system after an eight-month journey from Earth and blazed a trail across the high, thin atmosphere of Mars at the start of what those responsible for it had dubbed the “seven minutes of terror”.

Inside that aeroshell was the most advanced remote science system yet sent into interplanetary space by humankind, 80 kg (around 180 pounds) of science equipment packaged neatly into a rover vehicle itself just under a tonne in weight and powered by a “nuclear battery”. If all went well, those “seven minutes of terror” would end with NASA’s latest and most ambitious mission to the planet Mars safely on the surface of that world. If things went badly, a lot of people would be looking at almost a decade of their endeavours smashed to pieces along with the rover.

Of course, things did go well. The rover, dubbed “Curiosity” by an 11-year-old girl called Clara Ma following a nationwide competition held by NASA in 2008, landed safely and so wrote the first lines in what have been a remarkable year of operations on Mars.

Just over half-way through its primary phase of a full Martian year (about 1.8 times longer than a year here on Earth), Curiosity and the Mars Science Laboratory mission has already achieved a major part of its mission goal: to discover if Mars demonstrates any evidence for once having the kind of environment conducive to the formation of life.

And with the mission indefinitely extended beyond that primary mission phase (the rover’s RTG power system should be able to power it for around 14 years or so, so only the unforeseen accident or failure might now curtail the mission in less than that time frame), the opportunities for Curiosity to write many more new chapters in our understanding of Mars are considerable.

Over the last year, as an aside to my reporting on Second Life and virtual worlds (as well as one or two other things!), I’ve tried to provide a steady narrative on the mission in these pages (with more than a little help from NASA JPL!), I’ve done so as space exploration is of interest to me for assorted reasons, and because the reports seem to have resonated with some of you who regular read this blog (and thank you on both counts, for  reading the blog and the reports!).

Obviously, as with all things fresh and exciting, coverage of the mission in the early months was easy; such was the media interest in the story that information was flooding out of NASA’s Jet Propulsion Laboratory as the rover went through its month-long post-landing commissioning activities, and then started its first hesitant operations on the dusty, wind-swept floor of Gale Crater.

With the passing of a year, media interest has moved on. As a result, the science and engineering teams responsible for the mission have been able to focus more on their day-to-day work, and the updates coming out of NASA have slowed somewhat.

Curiosity is now well into the eight kilometre (five miles) drive to its next target: the lower slopes of Aeolis Mons (“Mount Sharp”), the mound surrounding the central peak of the crater. In the six weeks since departing “Glenelg” and “Yellowknife Bay”, where it had been engaged in science activities for almost six months, the rover has travelled almost a full kilometre.

That the rover is making “rapid” progress is down to two things: there are no planned science objectives for this phase of the mission (unless Curiosity happens across something completely unexpected and interesting), and the rover’s drive team have gained considerable confidence in the upgraded autonomous driving capability I reported on last time around.

Curiosity’s primary mission is not to find direct evidence of life, past or present, on Mars, but rather to see if ancient Mars once had the right conditions present in or on it for life to have possibly arisen. Gale Crater was chosen as a landing site with this in mind; since well before the mission it has been the subject of study from orbit by the likes of NASA’s Mars Odyssey and Mars Reconnaissance Orbiter and Europe’s Mars Express. That it has surface features which appear consistent with free-flowing water once having existed on Mars have been well-known, including the fact that “Mount Sharp” itself shows signs of having been in part formed from water-borne sedimentary deposits (it is thought Gale Crater may have once been filled with a lake). As such, it was anticipated that the rover would find evidence of free-flowing water having once been present within the 194-kilometre wide crater.

What wasn’t expected was the overwhelming evidence the rover came across in terms not only of sedimentary deposits, but also in what look to be ancient river beds sitting exposed on the floor of the crater, and rock and soil samples the on-board science systems have found to contain mineral and chemical elements and traces which point to a wet history in this part of Mars. What has been more exciting is that the mix of elements and minerals suggest the environment in the crater was once very benign towards life, so much so, that John Grotzinger, the mission’s Principal Investigator, was given to comment:

Continue reading “One year on, one kilometre travelled, a mission goal achieved” →

On July 16th, NASA’s Mars Science Laboratory rover Curiosity passed the one kilometre mark (0.62 miles) on its travels around Gale Crater. The milestone came eleven months after the one-tonne rover arrived on the surface of Mars on August 5th 2012.

Since that time, Curiosity has achieved a lot; it has travelled across several terrain types, it has studied the Martian atmosphere and meteorology and probed the ground underneath it for evidence of water. It has taken samples from the surface of Mars and drilled into rocks. It has analysed samples and returned a huge amount of data to Earth, including thousands of colour, black and white and high-resolution images. It has viewed its surrounding in 3D and – most intriguing of all – it has discovered very convincing evidence that Mars was more than likely once an abode suitable for the evolution of basic life.

Coincidentally, July 17th 2013 marked the half-way point for the rover’s prime mission of one Martian year (687 day or 1.88 Earth years). As the rover’s power system has a potential operating life of fourteen years, it is more than certain that, barring any accidents or major systems failure in the interim, operations will be extended well beyond the prime mission time frame. In this, Curiosity will not be alone; half a world away, NASA’s rarely mentioned Opportunity rover is fast approaching the tenth anniversary of what was originally a 90 day mission.

More Atmospheric Analysis

As mentioned above, Curiosity has been studying the Martian atmosphere using the Sample Analysis at Mars (SAM) suite of instruments. SAM has more recently been involved in analysing rock and soil samples collected by the rover’s scoop and drilling system, so it is easy to forget that it can also “sniff” and analyse Martian air, which it did for the very first time right back at the start of the mission. Since then, SAM has continued to periodically sample the Martian atmosphere, and it has already helped in further understanding the dynamics of the atmosphere and how it may have been lost over time.

SAM is able to measure the abundances of different gases and different isotopes in the Martian atmosphere. Isotopes are variants of the same chemical element with different atomic weights due to having different numbers of neutrons. In the first set of tests carried out, SAM compared the stable isotope argon-36 with its heavier cousin, argon-38. Since then, SAM has carried out a series of comparative tests on a range of isotope drawn from the Martian atmosphere, including carbon-12 and carbon-13 and both oxygen and hydrogen isotopes.

These tests, carried out using two different instruments within SAM – the mass spectrometer and tuneable laser spectrometer – during the first 16 weeks of the mission, measured virtually identical ratios of carbon-13 to carbon-12, with the ratios again pointing to the lighter isotopes having “bled off” into space from the upper portions of Mars’ atmosphere, rather than a process of the lower atmosphere interacting with the ground.

“Getting the same result with two very different techniques increased our confidence that there’s no unknown systematic error underlying the measurements,” said Chris Webster of NASA’s Jet Propulsion Laboratory. “The accuracy in these new measurements improves the basis for understanding the atmosphere’s history.”

The rate at which Mars is currently losing its atmosphere cannot be measured by Curiosity or any of the vehicles currently operating in orbit around Mars.  This will be the work of the Mars Atmosphere and Volatile Evolution (MAVEN) mission, which is due to be launched in November 2013.

Gullies on Mars: Water or Dry Ice?

While it is accepted that Mars’ atmosphere was once dense enough to support liquid water – Curiosity itself has found unmistakable evidence for free-flowing water to have once been present in the crater – evidence has also put forward to suggest that some features imaged on Mars and associated with possible water action may have been the result of another process entirely, as explained in this interesting NASA video.

Continue reading “One kilometre and counting” →

Curiosity has started on the long trek to Aeolis Mons, which NASA unofficially refers to as “Mount Sharp”. With some eight kilometres (5 miles) between the rover an its initial destination among the lower slopes of the mound, the drive is liable to take several months to complete. Nevertheless, the drive marks the start of the core part of the mission.

The journey started on July 4th, when Curiosity departed the sedimentary rock target NASA had dubbed “Shaler” within the “Glenelg” region of Gale Crater between “Yellowknife Bay”, where the rover had been carrying out drilling and other tasks, and the landing zone at Bradbury Landing. “Shaler” had actually been passed b the rover on its way to “Yellowknife Bay” and had, along with another location in “Glenelg” which had been dubbed “Point Lake”, been identified as a “target of interest” for the rover as it backtracked through “Glenelg” in order to start the long trip to “Mount Sharp”.

Point Lake first caught the interest of Curiosity’s science team in October and November of 2012. It caught the attention of mission scientists for two reasons: it forms a small cliff, and geologists love cliffs because they offer a sense of how a rock unit differs from bottom to top; plus images captured by the rover as it passed relatively close to the outcrop while en route to “Yellowknife Bay” revealed it to be full of holes. Why holes form in rocks can be due to diverse mechanisms, and Identifying which mechanism in particular is responsible can provide a greater understanding about the rock and its history.

The rover returned to “Point Lake” on Sol 301 / 302 (June 11th and 12th, 2013) and captured a further series of images using the Mastcam systems, some of which were then put together to create a mosaic.

The mosaic clearly shows that the upper and lower portions of the outcrop differ in composition, with the upper part having more holes while being more resistant to weathering. The holes themselves range in size from about that of a garden pea through to some larger than a golf ball’s diameter. Some additionally have raised rims, as if the material immediately around a hole is slightly more resistant than material farther from the hole. A number of smaller rock fragments towards the right-hand end of the mosaic look as if they might have fallen out of some of the holes, and some of these exhibit colour banding suggestive of material which could have coated the interior of a hole.

The science tem are still studying the images captured by the Mastcam system and by the rover’s Mars Hand Lens Imager (MAHLI), mounted on the turret at the end of Curiosity’s robot arm. Taken from a distance of just 4cm, the MAHLI images reveal pebble-like deposits within many of the holes covering “Point Lake”, and which have made the identification of the processes responsible for forming the holes somewhat harder, as both sedimentary and igneous processes could account for the “pebbles”.

Following the stop at “Point Lake”, Curiosity continued retracing its route back through “Glenelg”, reaching the vicinity of “Shaler” around Sol 313, where it remained for several days taking further images and manoeuvring in the area immediately adjacent to the rock formation. Then on July 4th, the rover started on the drive to “Mount Sharp” in earnest, initially travelling  back towards “Rocknest”, which it visited in September 2012, prior to skirting around it in a drive of some 36 metres (118 feet) between July 5th and July 8th (Sol 327).

Continue reading “The long trek and looking to the next decade” →