We’ve known for some time that water exists in some forms on Mars. The Viking program, which consisted of both orbiter and lander craft, showed that Mars’ surface had many characteristics that must have been shaped by water. Further probes such as Mars Odyssey and the Phoenix Lander showed that much of the present day water that Mars holds is present at the poles, trapped in the vast frozen tundra. There’s been a lot of speculation about how liquid water could exist on Mars today however no conclusive proof had been found. That was until today when NASA announced it had proof that liquid water flows on Mars, albeit in a very salty form.
The report comes out of the Georgia Institute of Technology with collaborators from NASA’s Ames Research Center, Johns Hopkins University, University of Arizona and the Laboratoire de Planétologie et Géodynamique. Using data gathered from the Mars Reconnaissance Orbiter the researchers had identified that there were seasonal geologic features on Mars’ surface. These dark lines (pictured above) were dubbed recurring slope lineae would change over time, darkening and appearing to flow during the warmer months and then fading during the colder months. It has been thought for some time that these slopes were indicative of liquid water flows however there wasn’t any evidence to support that theory.
This is where the MRO’s Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) comes into play. This instrument was specifically designed to detect water on Mars by looking at varying wavelengths of light emitted from the planet’s surface. Once the target sites were identified CRISM was then pointed at them and their surface composition analysed. What was found at the RSL sites were minerals called hydrated salts which, when mixed with water, would lower the freezing point of the water significantly. Interestingly these hydrated salts were only detected in places were the RSL features were particularly wide as other places, where the RSLs were slimmer, did not show any signs of hydrated salts.
These salts, called perchlorates, have been seen before by several other Mars missions although they’ve never been witnessed in hydrated form before. These perchlorates can potentially keep water from freezing at temperatures down to -70°C. Additionally some of these perchlorates can be used in the manufacturing of rocket fuel, something which could prove to be quite valuable for future missions to Mars. Of course they’re likely not in their readily usable form, requiring some processing on site before they can be utilized.
Data like this presents many new opportunities for further research on Mars. It’s currently postulated that these RSLs are likely the result of a shallow subsurface flow which is wicking up to the surface when the conditions are warmer. If this is the case then these sites would be the perfect place for a rover to investigate as there’s every chance it could directly sample martian water at these sites. Considering that wherever we find liquid water on Earth we find life then there’s great potential for the same thing to happen on Mars. If there isn’t then that will also tell us a lot which means its very much worth investigating.
The Mars Curse is the term used to describe the inordinately high failure rate for missions to our red celestial sister, particularly those that dare to touch the surface. It’s an inherently complicated mission as there are innumerable things that need to be taken into account in order to get something on the surface and a problem with any one of the systems can result in a total mission failure. One such mission that fell prey to this was the European Space Agency’s Beagle 2, a small lander that hitched a ride with the Mars Express craft all the way back in 2003. Shortly after it was sent down to the surface contact with the probe was lost and it was long thought it met its end at an unplanned disassembly event. However we’ve recently discovered that it made all the way down and even managed to land safely on the surface.
Like the Mars Exploration Rovers Beagle 2 would use the martian atmosphere to shed much of its orbital velocity, protected by its ablative heat shield. Once it approached more manageable speeds it would then deploy its parachutes to begin the final part of its descent, drifting slowly towards the target site. Then, when it was about 200m above the ground, it would deploy airbags around its outer shell to protect it from the impact when it hit the surface. Once on the ground it would then begin unfurling its solar panels and instrumentation, making contact with its parent orbiter once all systems were nominal. However back on that fateful day it never made contact and it was assumed the lander likely destroyed.
The information we now have points towards a different story. It appears that pretty much everything went according to plan in terms of descent which, as my very high level description of the process can attest to, is usually the part when things go catastrophically wrong. Instead it appears that Beagle 2 made it all the surface and began the process of deploying its instruments. However from what we can see now (which isn’t much given that the lander is some 2m across and our current resolution is about 0.3m/pixel) it appears that it didn’t manage to unfurl all of its solar panels which would have greatly restricted its ability to gather energy. My untrained eye can see what looks like 2 panels and the instrumentation pod which would leave it with about half the power it was expecting.
In my opinion though (which should be taken with a dash of salt since I’m not a rocket scientist) there must have been some damage to other systems, most likely the communications array, which prevented it from making initial contact. I’d assume that there was enough charge for it to complete it’s initial start up activities which should have been enough to make initial contact with the orbiter. Such damage could have occurred at any number of points during the descent and would explain why there was total silence rather than a few blips before it dropped off completely. Of course this is just pure speculation at this point and we’re not likely to have any good answers until we actually visit the site (if that will ever happen, I’m looking at you Mr Musk).
Still discovering Beagle 2’s final resting place is a great find for all involved as it shows what went right with the mission and gives us clues as to what went wrong. This information will inform future missions to the red planet and hopefully one day we can write off the Mars curse as simply a lack in our understanding of what is required for a successful interplanetary mission. Indeed the bevy of successful NASA missions in the past decade is a testament to this constant, self correcting trial and error process, one that is built on the understanding gleaned from those who’ve come before.
Mars is by far the most studied planet that isn’t our own, having had 46 separate missions launched to it since the 1960s and is currently host to no less than 5 active missions both in orbit and on its surface. Those missions have taught us a lot about our red celestial sister, the most intriguing of which is that it was once not unlike Earth, covered in vast swaths of ocean which could potentially have been host to all sorts of life. Even more interesting is that while it’s little more than a barren desert that’s only notionally above vacuum it still contains water ice in non-trivial quantities, leading many to speculate that somewhere its liquid form must also exist. The process by which Mars transformed from a lush landscape like ours to the wasteland it is today is still shrouded in mystery and is something that MAVEN, NASA’s latest mission to Mars, is seeking to solve.
MAVEN successfully launched yesterday atop of an ATLAS V rocket and will spend the better part of a year transiting the distance between Earth and Mars. Its primary objective is to investigate the evolution of Mars’ atmosphere to try and ascertain the factors that influenced its demise. Since the current prevailing theory is that a cooling planetary core led to a loss of a protective magnetic field which then allowed the solar wind to slow strip away the atmosphere many of the instruments aboard the craft are geared towards measuring solar particles around Mars’ orbit. The rest of the instrumentation is focused on directly measuring Mars’ atmosphere which will then allow scientists to reconstruct a full picture of it and the influences working on it.
I believe this is also (and someone feel free to correct me on this) the reason for its slightly abnormal orbit for when it arrives at Mars. Instead of taking the usual approach of having a near circular orbit (like the Mars Reconnaissance Orbiter) it instead has a highly elliptical orbit with the closet approach being a mere 150KM above the surface whilst its furthest point is 6200KM out. This would allow the craft to get good measurements of the levels of solar particles as it gets closer to the surface and how that compares to it further out. Considering the orbital period will also only be 4.5 hours it would make for some rather exciting flybys if you were aboard that craft but then again that’s not an orbit you’d use if you had people on board.
The orbit also has the rather unfortunate effect of limiting one of MAVEN’s more long term capabilities: it’s link back to Earth. MAVEN has a 10Mbit/s link thanks to an updated Electra array which is almost twice as powerful as MRO’s. However due to the rather eccentric orbit it won’t be available as often which will limit the amount of data that can be passed back. This doesn’t just impact the satellite itself though as whilst the rovers on Mars can communicate directly to Earth it’s not a very fast connection, so most offload onto a local satellite for their more data hungry applications. Since it’s currently only an augment to the other fleet of satellites around Mars this isn’t too much of an issue although it could present some contention issues later on the track when the other satellites are retired.
The science that MAVEN will conduct on its planned 1 year mission will prove invaluable in determining just what happened to Mars’ atmosphere and, by extension, what the chances are of any life existing on its surface today. It will also provide infrastructure for future missions, allowing them to be more ambitious in the goals that they attempt to reach. For now though it’s 1 day into its long trip to our celestial sister, quietly awaiting the day when it can finally start fulfilling its purpose.