Tag: Mars

Solar Conjunction

June sees Mars an Earth move into a period of solar conjunction, when they are one opposite sides of the Sun relative to one another. These periods of conjunction occur roughly every 26 months (the last having been April 2013), can see communications between Earth and vehicles operating on and around Mars severely disrupted due to interference from the Sun.

To prevent spacecraft at Mars from receiving garbled commands that could be misinterpreted or even harmful, the operators of Mars orbiters and rovers temporarily stop sending any commands. At the same time, communications from the craft to Earth are also stepped down, and science operations scaled back. Nasa started to do this on Sunday, June 7th, and both ESA and the Indian Space Research Organisation will be doing the same. For the two Mars rovers, Opportunity and Curiosity, it means parking up and no driving until after full communications are restored. General science observation will, however, continue.

One slight difference in all this will be with NASA’s newest orbiter at Mars: MAVEN (Mars Atmosphere and Volatile Evolution). This arrived over Mars in September 2014,  with the primary mission of determining the history of the loss of atmospheric gases to space and gain insight into Martian climate evolution. As such, MAVEN will continue monitoring the solar wind reaching Mars and making other measurements. The reading will be stored within the orbiter’s memory system and transmitted back to Earth once normal communications have been restored.

MOM Studies Mars’ Volcanoes

Another mission that hasn’t gained much attention since also arriving in orbit around Mars is India’s Mangalyaan (“Mars-craft”) vehicle, which reached Mars on September 24th, 2014. Referred to simply as the Mars Oribiter Mission (MOM) by most, the vehicle reached Mars just 2 days after NASA’s MAVEN orbiter, and like that craft, a part of its mission is focused on studying the Martian atmosphere.

MOM also carries a high-resolution surface imaging camera, and this has been busy returning some magnificent picture of Mars, including the brilliant picture of the planet reproduced above, which shows the north polar ice cap, the almost vertical line of the three massive Tharsis Bulge volcanoes of Ascraeus Mons, Pavonis Mons and Arsia Mons in the centre, the massive rise of Olympus Mons, the largest volcano in the solar system to their left, and the 5,000 kilometre scar of the massive Vallis Marineris to their right.

MOM’s camera is also capable of producing 3D images, and an example of this capability was released by ISRO on June 5th in the form of a dazzling image of Arsia Mons, the southernmost of the equator spanning Tharsis volcanoes. The image was actually captured on April 1st, 2015, and has a spatial resolution of 556 metres, and the camera some 10,707 kilometres from the surface of Mars when the picture was taken.

To give some idea of the scale of this massive shield volcano, it is 435 kilometres (270 mi) in diameter at its base, rises some 20 kilometres (12 miles) in height compared to the mean surface elevation of the planet, and is some 9 kilometres (5.6 miles) higher than the plains on which it sits. The caldera crater at its summit is 110 km (72 miles) across.

Continue reading “Space Sunday: conjunctions, volcanoes and space stations” →

In December 2014, I wrote about the Curiosity science team reporting they had detected odd “spikes” in methane levels in the Martian atmosphere as a result of analyses undertaken by the SAM (Sample Analysis at Mars) mini laboratory within the Mars rover.

Methane had first been definitively detected on Mars by the 2008 Phoenix Lander, although its presence had long been suspected and indicated. However, Curiosity’s discovery of two sudden sharp increases in the normal levels of traceable methane to some 7 part per billion – a ten time increase of the expected levels – suggested it had perhaps happened across some localised methane-producing source, possibly of organic nature (notes that “organic” in this case doesn’t actually mean “living things”).

However, the results have recently had some doubt cast upon them, and from within NASA itself. Kevin Zahnle, a scientist at NASA’s Ames Research Centre in California has been studying the data and suggested that the methane spikes could have come from a very localised source – a leaf of Earthly air previously trapped somewhere in the rover’s insides.

Depsite rigorous decontamination processes prior to launch, is is possible for air and gas pockets to get trapped inside a robot vehicle. This is actually what happened at the start of Curiosity’s sojourn on Mars: during its initial analysis of the atmosphere around it, the rover also detected abnormally high levels of methane, only for it to be tracked back to tiny amount of air carried aboard the rover leaking into the spectrometer carrying out the methane measurements. Zahnle suggests that a similar leak cannot yet be ruled-out as the cause of the 2013 and 2014 spikes.

Members of the Curiosity science team argue that as a result of the initial leak, they have taken every caution to prevent being misled again, and are confident that only the most exceptional of circumstances could result in SAM’s findings being the result of methane “trapped” somewhere inside the rover only get released well over a year after its arrival on Mars. However, they also admit that the potential for such a situation cannot be entirely ruled-out.

One of the arguments for the spikes being the result of contamination from within the rover is that similar readings haven’t since been recorded. A counter argument to this is that the levels SAM recorded could be the result of a yet-to-be-understood seasonal phenomena. To this end, the rover is going to be sniffing the air around it very carefully during late 2015 / early 2016 to see if it can detect any similar spikes.

Insight (in) to Mars

NASA’s next mission to Mars is scheduled to launch a March 2016. In keeping with the agency’s (roughly) alternating approach to surface mission to the planet, which switch between landers craft and rovers, the InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission is a lander mission.

As the full version of its name suggests, InSight is intended to probe the deep interior of Mars. In doing so, it is hoped the mission will not only add to our understanding of Mars, but also our understanding of the processes that shaped the rocky planets of the inner solar system (including Earth) more than four billion years ago.

Following its launch, InSight will cruise to Mars in a flight of roughly 6 months, landing on the surface in September of that year. After a check-out and calibration period, the science mission will commence in October 2016, with the overall surface mission expected to last 700 Sols (roughly 720 Earth days).

The reason Mars is being used in this way, rather than scientists simply studying the Earth to better understand the processes involved in shaping the rocky worlds of the solar system is that Mars are far less geologically active than Earth, it retains a more complete record of its history in its own basic planetary building blocks: its core, mantle and crust than does Earth.

The Lander for the mission is based on the successful design of the 2008 Phoenix mission, and will include technology and instruments that will be deployed onto the surface of Mars, including the HP3 “mole” which will burrow its way deep below the surface (see the artist’s impression under the headline to this piece) in an attempt to more accurately measure the amount of heat flowing outwards from the planet’s core.

Continue reading “Space Sunday: probing inside other worlds” →

Since my last Space Sunday update, NASA’s Curiosity rover on Mars has experienced successes to overcome some setbacks, major and minor.

The major success came in the form of what amounts to “corrective eye treatment” for the rover’s famous laser system, which has been zapping rocks and soil hundreds of thousands of times in order to analyse the resultant plasma, and thus understand the chemical and mineral composition of the target material.

Called ChemCam, the Chemistry and Camera instrument, actually comprises a laser system and a telescope / camera connected to a spectrograph. The laser is in fact two systems in one, a primary laser, used to “shoot” targets and generate the plasma, and a smaller rangefinder laser used to accurately focus the telescope camera on the intended target. However, several months ago, this rangefinder laser suffered an unrecoverable failure.

Since that time, the ChemCam team have had to rely on taking multiple images of a target rock at multiple focal lengths in order to determine the best focal length the telescope should use when the main laser is set to fire.

The problem here is that the images had to be taken, transmitted to Earth and then assessed by a team of scientists to determine the best focal length setting for the telescope, which then had to be transmitted back to Curiosity, which then had to make the required focal adjustments. Only then could the main laser be successfully fired and accurate images for analysis obtained by the telescope. Obviously, all of this is a very protracted process compared to the rover being able to automatically focus the telescope directly.

However, as a part of a recent software upload to Curiosity, the international team responsible for ChemCam were able to install an update that has resorted Curiosity’s ability to auto-focus the ChemCam telescope. Now, instead of having to send a series of images to Earth for analysis, the rover can simply run the images taken at different focal lengths and then run them through an on-board algorithm which then selects the optimal focal length for the telescope, allowing the laser firing to proceed.

A series of test firings using the new software were carried out on Thursday, May 21st, and the results weren’t only positive – they indicated the new, software-driven auto-focus technique actually yields better quality results than the original method.

The second success for Curiosity actually has its origins provide to my last Space Sunday report. As indicated at that time, Curiosity was attempting to reach a point dubbed “Logan Pass”, an area sitting at the head of a series of shallow valleys and marked by the confluence of two different types of rock.

At the time of my last report, Curiosity had already been diverted from the original route selected for getting to the target. Images of the route revealed it in part comprised what NASA calls “polygonal sand ripples”, which can cause the rover to suffer extreme traction difficulties and wheel slippage. As a result, a decision was taken to attempt the ascent to the desired science location via slightly rougher terrain; it didn’t work out.

“Mars can be very deceptive,” said Chris Roumeliotis, Curiosity’s lead rover driver said of the attempt. “There appeared to be terrain with rockier, more consolidated characteristics directly adjacent to these ripples. So we drove around the sand ripples onto what we expected to be firmer terrain that would give Curiosity better traction. Unfortunately, this terrain turned out to be unconsolidated material too, which definitely surprised us and Curiosity.”

Two attempts to climb over this “unconsolidated material” (that’s loose rocks, pebble, sand, and dirt to you and me) came to an end when the rover experienced wheel slippage beyond acceptable limits, forcing the drive to stop. Coupled with indications of some sideways slippage – something the rover certainly doesn’t want to encounter lest it topple over – the decision was taken to reverse course and try an alternative route offering a way to another point at which the two rock formations meet and are both exposed.

On Thursday, May 21st, the rover successfully completed a climb up a 21-degree incline to reach a point overlooking an area where the two different strata of rock sit one atop the other, presenting an environment rich in scientific potential, and where the rover may spend some time engaged in investigations.

Continue reading “Space Sunday: of detours and sailing the solar wind” →

April 16th, 2015 saw NASA’s Mars Science Laboratory rover Curiosity clock-up 10 kilometres (6.25 miles) on its odometer since it arrived on Mars 30 months ago, as it continues its trek up the slopes of “Mount Sharp”, the mountain-size mound at the centre of Gale Crater.

The rover is currently making its way through a series of connected shallow “valleys” on the slops of the mound – which is more correct names Aeolis Mons – as it continues upwards and away from the “Pahrump Hills” area it spent 6 months investigating, and towards its next major science target, an area the science team have dubbed “Logan Pass”, which is still some 200 metres away from the rover at the time of writing.

While only a distance of around 550 metres separates “Logan Pass” from the upper limits of “Pahrump Hills”, the rover’s gentle progress has been the result of several stops along the way in order to further characterise the different rock types Curiosity has been encountering, and to make important observations of its surroundings as the science team try to understand the processes by which the region’s ancient environment evolved from lakes and rivers into much drier conditions.

The rover’s progress up “Mount Sharp” has so far been through the lower reaches of the transitional layers which mark the separation points between the materials deposited over the aeons to create the gigantic mound and the material considered to be common to the crater floor. These transitional layers have been dubbed the “Murray Formation”, in honour of the late co-founder of The Planetary Society, Bruce Murray, and comprise a number of different land formations, “Pahrump Hills” being one of the lowermost. Logan Pass marks the start of another, dubbed the “Washboard unit”, and which comprises a series of high-standing buttes.

As several of the MSL reports in these pages have shown, Curiosity has already found considerable evidence that Gale Crater may once have been home to environments sufficiently benign to allow for the existence of microbial life. Whether or not those microbes survived down the millennia such that they are still present in the planet’s soil today, is not something the rover is equipped to determine; however, a recent report from one of Curiosity’s science teams  suggests that subsurface conditions are unfavourable to the support of microbial life.

The evidence for this comes in the form of perchlorate salts, and the effect they can have on their environment. Perchlorate was first detected in soil samples gathered by NASA’s Phoenix Mars Lander mission in 2008, while Curiosity found trace evidence for perchlorate in samples gathered early in its own mission.

What makes perchlorate interesting is that in cold temperatures, it is able to “pull” water vapour from the atmosphere and bind with it, lowering its temperature, potentially allowing it to form sub-surface brines which would be very destructive to microbial life.

It had been thought that the environmental conditions by which this might occur were limited to the near-polar regions of the planet. However, data gathered by Curiosity’s on-board weather station, called REMS (for Rover Environmental Monitoring Station) over the course of its mission suggests the night-time conditions in Gale Crater, are right for the formation of sub-surface brines throughout the year.

Continue reading “Space Sunday: hill climbing, the impact of salt, and landing a rocket (take 2)” →