Category: Space Sunday

No, this isn’t a return to coverage of Wars of the Worlds in  SL. November marks the start of the next round of missions to Mars, with two new orbiters about to depart Earth as a part of our efforts to better understand the Red Planet and its atmosphere. Meanwhile, and despite a lack of headline news, NASA’s Mars Science Laboratory (MSL) continues its own explorations of the Red Planet, as does its little cousin Opportunity, half a world away.

Driving Forward

During the last week of October, the MSL rover Curiosity chalked up another achievement making its first pair of back-to-back autonomous drives using its on-board capabilities rather than relying on assistance from Earth.

I’ve covered the benefits of Curiosity’s ability to “self navigate” and how it works in previous MSL reports. However, up until now the system has only been used after the rover has initially traversed a course carefully plotted by the drive team on Earth using images taken by the rover and from overhead passes of the Mars Reconnaissance Orbiter (MRO).

This was the case with the rover’s drive on Sunday 27th October, when it completed an autonomous drive after a plotted drive. However, on Monday 28th October Curiosity immediately resumed its autonomous drive without any input from Earth, heading for the next waypoint along the route which will eventually bring it into the lower slopes of “Mount Sharp”.

This waypoint, dubbed “Cooperstown”, is a rocky outcrop which had been identified as a candidate for examination by the rover in MRO images of the route to “Mount Sharp”. It is anticipated that Curiosity will spend no more than a day examining the outcrop, which is liable to be done predominantly using the instruments mounted on the turret at the end of the rover’s robot arm.

“What interests us about this site is an intriguing outcrop of layered material visible in the orbital images,” said Kevin Lewis of Princeton University and a participating scientist for the mission responsible for planning the “Cooperstown” activities. “We want to see how the local layered outcrop at ‘Cooperstown’ may help us relate the geology of ‘Yellowknife Bay’ to the geology of ‘Mount Sharp’.”

“Yellowknife Bay” is an area of Gale Crater which, alongside that of “Glenelg”, the rover spent some 6-months examining various rock formations and gathering samples for analysis.

The planned duration of the “Cooperstown” stop is in marked contrast to the rover’s last waypoint stop, and coupled with the testing of back-to-back autonomous drives, is aimed at accelerating Curiosity’s progress towards the desired destination of “Mount Sharp”. So far, the rover has traversed around one-third of the 8.6 kilometres (5.3 miles) separating the “Yellowknife Bay” area, which it left in July 2013, from the entry point to the lower slopes of “Mount Sharp”.

The ability for the rover to safely store data necessary for it to resume self-navigation in its onboard memory is also vital for future planning for Curiosity’s progress over the upcoming holidays, when it is hoped that multi-day operations for the rover can be planned and uploaded, allowing the rover to continue in a range of activities, including driving, rather than necessarily spending the entire holiday periods parked-up and performing static science.

The next key activity for the rover is the uploading of the third new version of the on-board software. Such uploads are periodically needed in order to both prepare the rover for upcoming aspects of the mission and to improve its capabilities. This next update will see improvements in the information the rover is able to store overnight for the purposes of autonomous driving, updates to the software controlling the robot arm which should further increase the ability to use the arm when the rover is parked on a slope – something which is likely to be needed once Curiosity starts exploring “Mount Sharp”.

Continue reading “A Martian invasion” →

In what has been something of a surprise to scientists around the world, findings from the Mars Science Laboratory (MSL) suggest the amounts of methane present in the Martian atmosphere, at least at near-ground levels, are at best negligible.

While it can be produced by non-organic, as well as organic means, methane has long been regarded as one of the tell-tale signs that life may have once existed on Mars – or even may still exist somewhere beneath the planet’s arid surface.

Using the highly sensitive Tunable Laser Spectrometer, a part of the Sample Analysis at Mars (SAM) science package aboard Curiosity, MSL has subjected six samples of the atmosphere gathered between October 2012 and June 2013 to analysis  – and failed to detect any signs of methane, trace or otherwise.

This has come as a surprise because previous data gathered by US and international scientists via a range of means have suggested that while not present in abundant amounts, methane is very detectable within the Martian atmosphere. So much so that some of those involved in MSL were extremely confident ahead of the mission that the rover would find clear evidence of the gas as a part of its analysis of atmospheric samples.

Europe’s Mars Express, for example, which started on-orbit operations in 2004, and is still functioning today, found strong evidence for methane within the atmosphere of Mars. Not long after this, NASA’s own Mars Global Surveyor (the precursor to the Mars Reconnaissance Orbiter which relays communications between Curiosity and Earth today), which operated in Mars orbit from September 1997 through to November 2006, also detected methane to a point where scientists where able to map its annual ebb and flow.

On Earth, methane (CH₄) is largely the by-product of two distinct activities: geological, such as through volcanic eruptions  – and Mars certainly has a fair few volcanoes, some of the largest in the solar system in fact; and via organic means. Either way, it tends to break down relatively quickly, so even trace amounts of it within Mars’ atmosphere suggest that it is being renewed somehow. Given that an erupting volcano on Mars is a tad hard to miss (see “some of the largest in the solar system”, above), a renewable source of methane has seen as evidence that either there is some as yet unknown chemical reaction going-on to create methane – or it may just be the result of outgassing from Martian microbes.

The amount of methane in the Martian atmosphere has never been particularly high; even the best analyses over the years have placed it at a peak of around 70 parts per billion, However, the TLS on Curiosity is a very sensitive piece of equipment. So sensitive that any trace amounts of methane in the Martian atmosphere must be below 1.3 parts per billion (around 10,000 tonnes in total throughout the atmosphere) in order for the TLS to miss it.

Responding to the findings, published on Thursday September 19th in Science Express, NASA has pointed out that the chances of future missions finding evidence of microbial life on Mars, past or present, aren’t entirely dashed. “This important result will help direct our efforts to examine the possibility of life on Mars,” Michael Meyer, NASA’s lead scientist for Mars exploration, said in a press release accompanying the report’s publication. “It reduces the probability of current methane-producing Martian microbes, but this addresses only one type of microbial metabolism. As we know, there are many types of terrestrial microbes that don’t generate methane.”

Continue reading “Of methane and waypoints” →

On Sol 376, August 27th 2013, Curiosity  achieved another mission milestone: the first use of the autonomous driving capabilities to fully drive itself through a potentially hazardous zone.

The autonomous navigation software – autonav – was uploaded to the rover following the April 2013 period of solar conjunction. It is designed to allow the rover to decide how best to handle driving safely on Mars, rather than constantly relying on command updates from Earth – something which can severely limit the rover’s daily progress if there are significant obstacles in the rover’s path or if the mission team want the rover to drive beyond the limits of what the  Navcams can see at the start of a day’s drive without routes having to be constantly re-plotted from Earth.

The drive of August 27th saw Curiosity successfully use autonomous navigation to cross ground that could not be confirmed safe before the start of the drive. While the drive team were able to establish a “bounding box” in which the rover was expected to keep during the day’s progress, a significant depression in the ground some 10 metres (33 feet) across could not be imaged in advance of the rover’s arrival, and so autonav was enabled in order for the rover to make its own way through the depression.

“We could see the area before the dip, and we told the rover where to drive on that part. We could see the ground on the other side, where we designated a point for the rover to end the drive, but Curiosity figured out for herself how to drive the uncharted part in between,” said JPL’s John Wright, a rover driver.

Crossing the depression required the rover to take several sets of stereo images of the terrain, compare them, determine potential routes to reach a the designated way-point, and then select the safest course to take.

While autonav has been used a number of times already in recent weeks, these have always been under controlled conditions and limited in scope. The Sol 376 traverse marks the first time Curiosity has been left entirely to its own devices to cross what has essentially been unknown ground for the mission team.  The drive means that the rover has now travelled about 1.39 kilometres (0.86 miles) since departing “Glenelg” and “Yellowknife Bay” early in July, and has a little over 7 kilometres (4.46 miles) to go before reaching the lower slopes of “Mount Sharp”.

Rapid Transit Route

To assist the rover’s progress, NASA have marked-out a “rapid transit route” using images from the High Resolution Imaging Science Experiment (HiRISE) camera aboard the orbiting Mars Reconnaissance Orbiter. This plots a rough course for the rover from “Glenelg” to the designated entry-point into the lower slopes of “Mount Sharp”, and which runs alongside a dune field which lays between the terrain the rover is on and the slopes of the mound itself.  Several potential waypoints have been identified along the route where the rover may stop for a few days at a time to allow further science work to be carried out.

Continue reading “Crossing the unknown” →

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” →