Sol 371: Driving Record and New outcrops

Curiosity has completed a record drive on sol 371 with a single drive totalling 110m, the longest ever single distance drive in the mission. The reason for these long drives is because the rover team can now see further than usual because of the nature of the terrain. This allows them to plan more ambitious drives.

Meanwhile the rover stumbled upon an interesting outcrop (sol 370) though that will not stop her from planning even longer drives as soon as possible.

The new outcrop looks like it is made up
of course particles cemented together
just like the ones at Glenelg.
(NASA/JPL/MSSS)

You can get a sense of the new terrain (which should be continuous with the top layers of rocks back in Glenelg) in this b/w navigational image taken on sol 371:

Sol 371 mosaic showing the extent of the new outcrop (NASA/JPL/MSSS/Abraham Samma)

Judging from the images from the laser-camera combo instrument ChemCam, these rocks could be water related as you can see the rounded pebbles like in this ChemCam image taken on sol 370:

ChemCam shot of a target within the outcrop.
The camera is designed to magnify laser target areas
millimetres across. Notice the rounded particulates
some held precariously by cementing material
like the one on the right of the centre
(NASA/JPL/LANL)

The rounded surface of larger pebbles implies water and not wind (which can't easily transport and therefore smoothen larger pebbles) as the agent that eroded them while being transported in a stream.

Alluring Martian Moons

I thought of writing only about the moons of Mars today so here goes:

One of the most enchanting things about Mars is its contradictory mix of alien qualities combined with aspects that make the planet more earth-like than any other body in the solar system. It has a sky that’s pink instead of blue, polar caps made of a combination of frozen carbon dioxide and water rather than just water ice and it has natural satellites, two of them, called Phobos (meaning ‘fear’ in greek) and Deimos (which means ‘terror’), appropriate companions for a planet named after the Roman god of war.

Phobos was discovered in 1877 by Asaph Hall, an American astronomy. He also discovered Deimos a few days ago the same year.Phobos is the bigger of the two with dimensions spanning 28 km by 20 km. Deimos measures 16 km by 12 km, almost half of Phobos’ size. From the surface they appear to move across the Martian night sky in opposite directions; Phobos rises from the west and sets in the east while Deimos does otherwise. This can be accounted for when one considers their orbital periods, i.e. the time it takes for a revolving body to complete a full circle around a point of focus.

Phobos in false colour by Mars Reconnaissance Orbiter
in 2008. Notice the 'big hole' to the right called Stickney and the
the strange grooves leading out of it (NASA/JPL//MSSS/UA)

By Kepler's third law of planetary motion, we expect the period of orbiting bodies to increase with their distance from the foci. Phobos, orbiting closest to Mars (approx 9300 km), circles Mars once every 7.7 hours. This means that essentially Mars (which rotates around its axis every 24.6hours) is essentially playing catch up with its moon. So, instead of the moon appearing to rise and set from east to west like things here on Earth (which move slower than the Earth across the sky) it appears to rise from the west and set in the east. This is similar to what you would see along the highway. When you pass a slower car at high speed, he appears to be moving backwards. An overtaking Formula One race car would appear to be moving forwards, leaving you in the dust! It’s all relative motion. Taking all this we see that an observer on Mars would see Phobos rise and set every 11 hours roughly. For Deimos (lying almost 23,460km away from Mars) with its orbital period of 30.3hours, you would see it in the Martain sky every 5.45days roughly.

The 'moon movie' from Curiosity clearly
shows the relative opposing motions
of the two moons. Notice Stickney
crater in the leading edge of Phobos
(NASA/JPL/MSSS)

 Phobos’ surface features are more prominent and diverse in nature than that of Deimos whose features appear softer. The most prominent feature on Phobos is the massive Stickney crater (named by the International Astronomical Union after Asaph Hall’s wife), measuring 9 km in diameter. Strange grooves that resemble a spider’s legs appear to radiate from the crater. It is still unclear how these lines actually formed but two schools of thinking suggest that they’re cracks that could have formed as a result of the impact that formed Stickney in the first place (which being half the size of Phobos implies a massive event that could have ripped the moon apart) or they may be a result of the debris that was flung from the impact sit landing back onto the surface and producing chains of craters that coalesced into grooves. The interesting thing about these grooves which measure hundreds of metres across and tens of metres deep is that they don't quite seem to radiate perfectly from the crater itself and new data from the European orbiter Mars Express suggest that the impact ‘cracks’ scenario may not be as correct as first impressions suggested and that the grooves are actually independent of the Stickney crater information. They are indeed are result of falling back of impact debris but not necessarily from the impact that caused Stickney.

A good relief view of the grooves of Phobos(Commons)

Deimos is an interesting body in that it doesn’t sport as much features as its bigger counterpart. In fact it only has 2 officially named surface features; Swift and Voltaire, Deimos’ two of the moon's larger craters measuring 1km and 1.9km respectively in diameter named after writers who wrote about the moon more than a hundred years before its discovery. The subdued appearance of the surface features suggests a thick layer of powdered regolith covering most of the surface.

Deimos in false colour courtesy of MRO.
The two faint craters that form
an unsymmetrical figure 8
to the lower left are Swift and Voltaire (NASA/JPL/MSSS/UA)

The composition of the two moons resembles that of some classes of asteroids, rocks that failed to form planets during the formation of the solar system 4.6 billion years ago. Phobos and Deimos’ compositions resemble a class called C-type (classes are determined according to the spectral signature of the asteroids i.e. the amount of light reflected by these objects at different wavelengths) the most common of types. These are dark, carbonaceous bodies with poor reflectance and very little minerals. Some suggestions indicate a relationship with D-type which features a reddish colouration and maybe organic compounds and water. Very little hydration has been detected on surface of these moons but there may be some water ice under all that layer of regolith. The relatively low densities of the moon (2000 kg/m^3 for Phobos and 1000 kg/m^3 for Deimos) suggest some form of porosity in the bodies, i.e. they're literally space fluff; rocks that have not quite come together to form a thorough solid body.

Their similarities to asteroid classes and their general appearance suggest that they are indeed captured asteroids that somehow got trapped in Mars’s gravitational well, perhaps with a little help from an ancient thicker atmosphere that helped slow these bodies down to their present orbits. The near circular, near-zero inclinations of the orbits however suggest the capture theory for the formation of the Martian moons may not be adequately explanatory. Capture should result in an elliptical orbit, not near perfect circles. In short, we still have a lot to learn about these two small moons.

So far we have only had flybys of these moons with Mars orbiting spacecrafts like Mariner 9, the Viking series in the 1970/80s, the Mars Global Surveyor, Mars Express and the latest Mars Reconnaissance Orbiter. Russia did try to send 3 orbiter and landing mission to Phobos; Phobos 1 and 2 and the recent Phobos-Grunt in 2011. The first two were launched in the 1980s and Phobos 1 failed en route, Phobos 2 got near enough to get pics but also failed and Phobos-Grunt failed to get beyond Earth orbit and burned up during reentry in January 2012. It would have been wonderful to have a spacecraft studying this moon, both believed to contain details about the old nebula cloud from which our solar system emerged. Other missions are on the drawing boards including an American candidate called Phobos Surveyor.

So the Martian moons continue to beckon us on! Until then, it is up to the current orbiters and rovers to survey these forgotten rocks whenever they have time. The recent observations made by Curiosity will be used to improve our understanding of the orbital mechanics of these moons in order to continue to predict their future movements with great(er) accuracy.

Sol 365: Steady driving

Curiosity is steadily making its way towards Mount Sharp and so far she's making good time and just like that the 2km mark is just metres away as of sol 365.

This calls for a colour panorama!

A 360 degree partial true colour panorama shot by the rover's
Mastcam (left eye)on sol 364. (NASA/JPL/MSSS/Panorama by Abraham Samma)

Besides showing a gorgeous view of the mount and the faraway walls of Gale carter there are also some subtle but interesting features present in this seemingly monotonous view.  If you look carefully on the right side of the panorama, you'll notice a conspicuous pile of black basaltic boulders (rocks of volcanic origin). The boulders appear to sit on a mound which might suggest an eroded intrusive volcanic feature like a dike though like I've said many times before, I'm not a geologist (professional anyway)! Earth has plenty of such features too so these are typical to both planets. Whatever they are they warranted more remote sensing by the rover which I've stitched accordingly. This shot was made the next sol before the rover drove around 26m more:

Sol 365 shot of the boulder mound with the right eye
of the Mastcam (NASA/JPL/MSSS/mosaic by Abraham Samma)

The same could be said for the one next to the rover's tracks to the left of the first panorama and many other similar sites around the area which are revealed beautifully in the HiRise map.

That's it for this update. Just incase you haven't seen, check out this beautiful gif animation made from images captured on the night of sol 351. It shows the moon Phobos (the largest of Mars' two moons) crossing and eclipsing Deimos (the smaller of the two) for a few seconds. Beautiful! I'd like to write more about these two moons later as there is so much to talk about these two enchanting bodies than can be said in this brief update.

The entire passage took 55 seconds
(NASA/JPL/MSSS)

Until then, stay curious!

 

Sol 355: ONE YEAR ON MARS!

It has been almost one year since an object from Earth came streaking down the beige Martian sky to begin one of the most unique and iconic surface mission ever undertaken by a human-built probe on the surface of Mars. Already Curiosity has forced textbooks to be changed as the mission’s vast array of scientific instruments (few of which have never been used on another planet before) uncovers more and more information about this red planet’s environment, past present and also laying the foundations for an eventual human-led expedition.

To celebrate this occasion, NASA has put together some interesting multimedia on the mission website as well as a useful infograph that summarise the main discoveries made by the rover during its time here.

An infograph that summarises all of
Curiosity's discoveries to date (NASA/JPL) 

And just in time for the celebrations, we have here a nifty image sent down by the rover on the 1^st of August this year, showing the two moons of Mars, Phobos and Deimos in a single shot, a mission first. The image was originally spotted by blogger extraordinaire Emily Lakdawalla of the Planetary Society.

This image was taken at night by Curiosity on sol 351.
You can clearly see the potato-like ruggedness of
big Phobos to the left and little Deimos to the right
(NASA/JPL/MSSS)

 I originally wanted to post this yesterday but I missed because my internet connection was down. Now I'm glad that I didn't post otherwise I would have missed this really brilliant video. It shows the flight spare of the SAM instrument on Earth being programmed to sing Happy Birthday to Curiosity! Well not exactly sing rather it is vibrating at certain frequencies that our brain interprets as a Happy Birthday jig. Its pretty awesome to watch and listen. The vibrations serve to nudge samples along the way in the many pipes and chambers inside the instrument.

This mission is just now ready to crank the gears up a notch. Curiosity is fast on its way to the ingress point south east of its position where it will start trudging Mount Sharp’s lower slopes and sampling ancient rock dating back more than 3 billion years ago. This was during a time of Mars’ geological history dubbed the Noachian era when the planet’s environment evidently could support liquid water in great amounts on the surface and the atmosphere was thick enough to prevent this water from boiling away. Whether life could be supported or was ever supported is another question entirely, one that may never be answered fully by Curiosity given the aim of the mission and the range of its instruments. Such questions can only be answered scientifically when we have a sample of Mars in our labs here on Earth. This would require a sample return mission and there a number of proposals on the drawing boards seeking funding and the next Martian rover in 2020 will be a part of that future effort in one way or another. Other countries and organisations like Europe’s European Space Agency, India’s Indian Space and Agency, Russia and China are all seeking to expand their Mars exploration programs one way or another.

A model of the coming Indian Mars Orbiter, the Mangalyaan or
'Mars-craft' in Hindi (photo by: Arunangsu Roy Chowdhury)

Despite the undeniable scent of presence national competition and pride amongst these efforts, there is a universal scientific rallying to know this planet better which helps the unify humans and overcome national boundaries if only a little. Mars exploration is important to us and Curiosity is just the beginning of a global
wave of missions that are soon to be.

WHY ARE WE HERE?

This is what I want to reflect on today; what are we doing here? Why are we spending all this dough on these cool machines to send home fantastic vistas of faraway worlds? How do we convince the most demanding of auditors, i.e. the ordinary citizen, that space exploration and fundamental scientific research is as important as fighting poverty and world hunger? Immediate benefits are not apparent in some sciences such as astronomy and pure mathematics so why do we have to give damn?

In 1970, Sister Mary Jucunda, a nun based in Zambia, decided to write to a man named Dr. Ernst Stuhlinger who was at the time associate director of science at NASA’s Marshall Space Flight Centre. It was just within a year after America’s successful landing of men on the moon and the Apollo program that did it was well under way in sending more expeditions to the moon. Hence the nun’s letter was well justified both in the reason and time. In it she asked Dr. Stuhlinger how he could suggest spending billions of dollars on such projects at a time when so many children were starving on Earth. The thoughtful doctor did reply and today we can read his succinct explanation to the nun here. I believe that his reply still holds water in our post-cold war era. In any case his logic may be exactly what we need to overcome so many challenges today. I encourage readers to visit the given link to read the letter. Its a bit long but I don't think we should expect anything less for a question that touches on such important issues.

There is a reason why this era is called the era of Information. It is fundamental research and development that which is powering everything from our national economies to our food production (crops today are far more resilient thanks to advances in genetics) to the very way we learn, treat diseases and coordinate massive humanitarian interventions. It may be very hard to believe that our humble rover Curiosity is part of that wave of new knowledge but in actual fact she is! Here analytical instruments, the CheMin and SAM, are revolutionary because they have been ingeniously miniaturised to fit into the rover’s body and still produce high quality data rivalling their bigger cousins that reside in terrestrial laboratories. Curiosity is a technological feat whose advances will continue to echo well into the future of humanity, long after she completes her mission at Gale crater.

The age of discovery never started with the European conquest of the world nor has it ever ended. It all began when a certain being who walked on two legs and lived in Africa decided in his heart there is something over the hill that’s better than what is here and that we must walk in that direction to find it. We are still walking that walk up to today and we will continue that walk until we, as the poet T.S. Eliot put it, “...arrive where we started and know the place for the first time.”

Meanwhile our rover continues on its way to Mount Sharp in earnest. What we will see at the end of this spurt I cannot say nor can anyone else. But what I’m pretty sure about is that I’ll be there to see it when it comes and I hope you too dear readers will be there too, waiting to see what lies over the distant hills like our ancient ancestors.

Panoramic view from Curiosity on sol 354. A lonely sand drift can be seen
in the foreground near centre. Currently the rover has completed over a mile
of roving. (NASA/JPL/Panorama by Abraham Samma)

Stay curious!