Tag Archives: MSL

Small blue dot on a red planet

CuriosityOn Wednesday April 16th, NASA JPL released a remarkable image captured using the High Resolution Imaging Science Experiment (HiRISE) camera on the Mars Reconnaissance Orbiter (MRO).

The image reveals the the Mars Science Laboratory, Curiosity parked alongside the multi-layered rock formation dubbed “The Kimberley”, as it prepares to undertake a range of science studies in the area.

The image was captured by MRO on April 11th during an overflight of the rover’s position as it sits at the foot of a rocky butte mission scientists have dubbed “Mount Remarkable”, and which forms a part of a multi-layered rocky location which has been dubbed “the Kimberley” due to its resemblance to a similar confluence of rock types found in Western Australia.

A rover’s progress: Curiosity, the blue form just off-centre in this false-colour image, sits at the foot of “Mount Remarkable”, a butte located in the area mission scientists have dubbed “the Kimberley”. the rover’s tracks can be seen leading back toward the top left corner of the image, where it entered the region on March12th, 2014. This

“The Kimberley” is an area of four distinguishable rock types exposed close together in a decipherable geological relationship to each other.  As such, they should provide further clues about ancient environments that may have been favourable for life. It is of particular interest to Scientists because like “Yellowknife Bay”, where the rover spent several months analysing and drilling rocks, “the Kimberley” demonstrates features which suggest that some of the rocks have only been exposed for a short time, geologically speaking.

This matters because Mars doesn’t have a magnetosphere and thick atmosphere like Earth’s, which protect us from energetic particles from space that break down organic material. So, rocks that have been exposed or close to the surface for a very long time are less likely to contain complex organic material, which might either be the remnants of past life, or help inform scientists about past habitability, the potential to support life in an area – as was the case with “Yellowknife Bay”.

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Sitting on the Kimberley and seeing spots

CuriosityCuriosity officially reached its next planned waypoint – dubbed “the Kimberley” on Wednesday April 2nd, 2014, with a final drive of some 30 metres (98 feet), after detouring from its planned drive route to reduce the amount of wear and tear being suffered by the rover’s aluminium wheels, the result of traversing some particularly rough terrain for several months.

“The Kimberley” was identified from orbit in 2013 as a possible location of interest during the rover’s drive down towards the point at which it will start its explorations of the lower slopes of “Mount Sharp”. It is an area of four distinguishable rock types exposed close together in a decipherable geological relationship to each other.  As such, they should provide further clues about ancient environments that may have been favourable for life.

A mosaic of “The Kimberley” created by images taken by Curiosity’s Navcam on Sol 589 (April 2nd, 2013), at the conclusion of the rover’s final drive to reach the waypoint. The outcrop at the center of the image is a category that the rover team scientists call “striated,” from its appearance in images taken from orbit before the rover reached this area. Farther in the distance, the striated type is overlain by other types. On the horizon, slopes of Mount Sharp – the mission’s long-term destination – are on the left and the rim of Gale Crater is on the right (click to enlarge)

As a major waypoint, “the Kimberley” will form an extended stopover for Curiosity which, while unlikely to be as long as the 6 months the rover spent exploring and examining “Glenelg” and “Yellowknife Bay”, will still be in the order of several weeks. The first part of this work is study the area in more detail, and the location occupied by the rover and the end of its April 2nd drive  – Sol 589 for the mission – is ideal for this. A slight rise compared to the surrounding terrain, it provides an excellent vantage point from which the rover can survey its surroundings, allowing mission scientists to comprehensively review the area and plan the coming science programme in finer detail than can be achieved when using orbital images alone. The science work is expected to involve observation of the surrounding region, sample-gathering from the rock formations, and onboard analysis of the samples gathered.

As I’ve previously reported, a cause of concern for mission personnel of late has been the amount of wear and tear the rover’s six aluminium wheels have suffered during the drive south from “Yellowknife Bay”. While the matter is far from serious in terms of impeding the rover’s manoeuvring or driving capabilities, with Curiosity’s nuclear battery offering the chance for a mission as much as 20 years in duration barring unforeseen circumstances, and what might provide to be a punishing climb up into the slopes of “Mount Sharp” still to come, the rover was directed onto less harsh terrain – comparatively speaking – in February 2014. Since then the mission team have been periodically checking on the wheels for further signs of damage and, as I noted last time around, the wear on the wheels is now around a tenth of that which had been experienced prior to the diversion. Nevertheless checks are still being carried out – including during the period in which this report was being written, as demonstrated by the raw image below, taken directly from the NASA image archive for Curiosity.

An image of one set of Curiosity’s rear wheels captured by the Mars Hand Lens Imager (MAHLI), located on the turret at the end of the rover’s robotic arm, on Sol 595 (April 9th, 2014). Note the jagged hole punched through the 40-cm (16-in) wheel (the rounded holes visible on the far side of the wheel are not signs of damage, but a part o the morse code for “JPL” deliberately cut-in to the wheels to help measure wheel rotation and slippage. This is a raw image, as posted by NASA on receipt from Curiosity, and without any white-balance post-processing (click for full size)

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On reaching Kimberley, managing communications and solving mysteries

CuriosityIt’s been a quiet time for the last three weeks as far as news from NASA’s Mars Science Laboratory is concerned. There have been a couple of reasons for this.

The primary reason is that the rover is on a slow but steady drive towards its next intended science waypoint while en route to the lower slopes of “Mount Sharp”. At the start of February, that waypoint had been around half a kilometre from the rover. However, concerns over the amount of wear and tear being suffered by the rover’s wheels as a result of traversing very rough terrain meant that Curiosity took a diversion.

While this put the rover on much smoother – comparatively speaking – terrain, it also meant the route to the waypoint had become more circuitous, requiring Curiosity cover around a kilometre in order to reach its intended stopover. In addition, engineers have been periodically checking the amount of damage to the wheel which may be accruing, further slowing daily progress, as well as continuing to test alternative driving methods to further ease the load on the wheels – such as letting the rover drive backwards towards its destination. However, the good news is that in the month since crossing Dingo Gap on February 18th, wear on Curiosity’s wheels has been around one-tenth what had been experienced per month during the months traversing the rougher terrain.

The long drive south. Murray Buttes mark the point at which Curiosity is expected to start the traverse onto the lower slopes of “Mount Sharp”, which forms a natural break in a line of dark sand dunes between the rover and the mound. “Kimberley” marks the next stop on the way (click for full size)

Additional tests using Curiosity’s test bed “twin” on Earth have revealed that the rover could sustain substantially more damage than incurred so far, including breaks in the wheel treads themselves, and still remain operational. However, given the potential duration of the mission – Curiosity’s nuclear “battery” could provide it with an operational life measured in a couple of decades barring other failures – means caution is key at this stage of the mission.

“The wheel damage rate appears to have levelled off, thanks to a combination of route selection and careful driving,” said JPL’s Richard Rainen, mechanical engineering team leader for Curiosity. “We’re optimistic that we’re doing OK now, though we know there will be challenging terrain to cross in the future.”

MRO Computer Glitch

The other break in news, although brief in nature, was caused by an unexpected issue with Curiosity’s primary communications relay between itself and Earth – the Mars Reconnaissance Orbiter (MRO) unexpectedly switched itself into a “safe” operating mode on Sunday March 9th. This immediately brought a cessation in the orbiter’s communications relay function for both Curiosity and Opportunity on the surface of the planet, although it did not put either rover entirely out of communications with Earth.

An artist's impression of the Mars Reconnaissance Orbiter orbiting the planet

An artist’s impression of the Mars Reconnaissance Orbiter orbiting the planet

While MRO forms the primary means of communications between the surface of Mars and mission control at NASA’s Jet Propulsion Laboratory facility at the California Institute of Technology, the rovers on Mars can also use NASA’s Mars Odyssey as a relay – and, should it be required, Europe’s Mars Express. However, Mars Odyssey, which has been operating around Mars for almost twelve and a half years, has much lower bandwidth and data transmission rates compared to MRO, which reduces the amount of information which can be relayed to Earth at any given time.

MRO’s issue first became apparent on March 9th, when the orbiter performed an unplanned swap between its duplicate computer systems. This is the prescribed response by a spacecraft when it detects conditions outside the range of normal expectations; the safe mode is initiated to reduce the risk of whatever caused the out-of-range event from being repeated by the second computer and potentially permanently harming the vehicle while matters are investigated. MRO has experienced unplanned computer swaps triggering safe-mode entry four times previously, most recently in November 2011, the root cause of which still hasn’t been clearly determined.

The March 9th safe mode entry also included a swap to a redundant radio transponder on the orbiter, marking the first time this has happened during the vehicle’s eight years in orbit around Mars. Whether or not the transponder issue triggered the computer swap-out is unclear. However, after carrying out a series of diagnostics on MRO from Earth, the mission team began bringing the orbiter back-up to full operational capabilities on March 11th, leaving it operating on the computer the swap-out switched to, together with the previously redundant radio transponder.

“The spacecraft is healthy, in communication and fully powered,” Mars Reconnaissance Orbiter Project Manager Dan Johnston said on March 11th. “We have stepped up the communication data rate, and we plan to have the spacecraft back to full operations within a few days.”

Charting a New Frost Channel

Since that event, MRO mission scientists have released a photo comparison showing the active nature of the Martian environment. The image shows two pictures of the same slope in the wall of crater Terra Sirenum, located in the southern highlands of Mars. There were captured some two and a half years apart (roughly equivalent to 1.2 Martian years), in November 2010 and May 2013 respectively.

Side-by-side: an image of Terra Sirenum crater walls taken in November 2010 compared with an image of the same region taken in May 2013, complete with freshly-carved gully and outflow fan (light areas)

Side-by-side: an image of Terra Sirenum crater walls taken in November 2010 compared with an image of the same region taken in May 2013, complete with freshly carved gully and outflow fan (light areas)

The right-hand (May 2013) clearly shows the creation of a new gully down the inner wall of the crater, created when material flowing down the older channel broke out to form a new channel and corresponding fantail deposit. While the material responsible for the new gully was liquid in nature, as the event occurred in the Martian winter period in the southern hemisphere, it is believed that carbon dioxide ice, and not water, played the major role in forming the new channel.

NASA had previously experimented with dry ice to see if it could be responsible for such gullies, with interesting results.

 

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Sometimes going backwards is the best way forward

CuriosityCuriosity is once more moving forwards – by going backwards.

Since crossing the “Dingo Gap” sand dune, the rover has been on terrain dubbed “Moonlight Valley” which is far smoother than has been encountered in recent travels, exactly as the mission team would hope would be the case. Nevertheless, precautionary measures are still being used to offer Curiosity’s aluminium wheels some additional relief after a routine inspection of them revealed some had suffered much greater wear and tear than had been anticipated crossing some very rugged terrain.

While the damage to the wheels is not an immediate threat to the rover, mission planners were aware it could happen, and so have been considering various alternatives to minimise further undue wear. One of these alternatives involves the rover proceeding by driving backwards.

A white-balanced look back at the “Dingo Gap” sand dune Curiosity drove over on February 9th (Sol 538) to reach smoother driving terrain. For scale, the distance between the parallel wheel tracks is about 2.7 metres (9 feet) across (click to enlarge)

Theoretically, the design of the rover means that it can make forward progress either by driving with its front end (mounting the robot arm and science turret), or with its rear end, the large RTG cooling system, facing the direction of travel. However, the technique has never been fully tested on Mars, only having being tried over any significant distance using Curiosity’s Earth-based test bed twin; but with much smoother terrain now before the rover, mission managers were eager to discover how well Curiosity could drive when travelling backwards.

“We wanted to have backwards driving in our validated toolkit because there will be parts of our route that will be more challenging,” said mission Project Manager Jim Erickson at  NASA’s Jet Propulsion Laboratory, Pasadena, California. To this end, on Tuesday February 18th, Sol 647 of the mission, Curiosity covered just over 100 metres (329 feet) whilst driving backwards, a traverse which was also the first long trek the rover has made in more than three months, bringing the total distance it has driven since arriving on Mars in August 2012 to some 5.21 kilometres (3.24 miles).

Casting a long shadow: a black-and-white Navcam image captured by Curiosity at the end of its 100-metre reverse drive on Sol 547 (February 18th, 2014). The linear markings near the rover’s shadow are not wheel marks but surface patterns in the ground over which it is travelling (click to enlarge)

With the reverse driving now proven, Curiosity is set to resume its primary mission, which will see it make its way to an area previously referred to as “KMS-9″, comprising three different terrain / rock types offer a relatively dust-free area, and which has now been renamed “Kimberley” after a region in north-western Australia noted for its ancient, exposed rocks.

Following the February 18th drive, Curiosity faced a 1.1 kilometre curving trek to reach “Kimberley”. Once there, the rover will stop there to conduct further science activities, including gathering further rock samples using the turret-mounted drill. At the same time, mission managers will use orbital imagery to select the preferred route the rover will be instructed to take in order to continue onwards to its primary destination: the lower slopes of “Mount Sharp”.

“We have changed our focus to look at the big picture for getting to the slopes of Mount Sharp, assessing different potential routes and different entry points to the destination area,” Erickson said, commenting on the need to reassess the route. “No route will be perfect; we need to figure out the best of the imperfect ones.”

Reaching Kimberley: the white line marks Curiosity’s route. Prior to cross “Dingo Gap” (top right), the rover’s route would have been more-or-less directly to “Kimberley” (lower left). Since crossing the dune onto smoother terrain, the rover has travelled some 100 metres (to “547″), with the yellow line showing the revised route to “Kimberley” the rover will be negotiating (click to enlarge)

It is not clear how long the rover will remain at “Kimberley” once it arrives there; part of this decision will likely only be made once the rover have been able to survey the area for itself.

MSL reports in this blog

Images and video courtesy of NASA / JPL.