Tag: Spaceflight

Space Sunday: of water, Apollo and space spies

Posted on by Inara Pey

CuriosityThe Curiosity rover team have released a further study showing that ancient Mars was capable of storing water in lakes over an extended period of time, and that this water was a principal component in the creation of “Mount Sharp”, the mound at the centre of Gale Crater, currently being investigated by the NASA rover.

This forms the latest in a series of reports on the subject of water on Mars and in Gale Crater to be published by the Curiosity science team, and comes almost a year after I wrote about studies released by the team which detailed how “Mount Sharp” – more formally known as Aeolis Mons – was most likely formed by sediments laid down  by successive wet period in Mars’ ancient past.

“Observations from the rover suggest that a series of long-lived streams and lakes existed at some point between about 3.8 to 3.3 billion years ago, delivering sediment that slowly built up the lower layers of Mount Sharp,” said Ashwin Vasavada, Mars Science Laboratory project scientist, discussing the new report.

In December 2014, NASA issued a report on how
In December 2014, NASA issued a report on how “Mount Sharp” was likely formed. On the left, the repeated depositing of alluvial and wind-blown matter (light brown) around a series of central lakes which formed in Gale Crater, where material was deposited by water and more heavily compressed due the weight of successive lakes (dark brown). On the right, once the water had fully receded / vanished from the crater, wind action took hold, eroding the original alluvial / windblown deposits around the “dry” perimeter of the crater more rapidly than the densely compacted mudstone layers of the successive lake beds, thus forming “Mount Sharp”

However, until Curiosity actually started studying “Mount Sharp” in detail,  the accuracy of the earlier studies couldn’t be completely verified. The latest results from the rover indicate that these wetter scenarios were correct for the lower portions of Mount Sharp, and that the filling of at least the bottom layers of the mountain occurred over a period of less than 500 million years, mostly as a result of material deposited by ancient rivers and lakes.

The new report also comes on top of confirmation that the recurring slope lineae (RSL) features seen on Mars from orbit are most likely the result of outflows of water which are occurring today. together they are reshaping some of the thinking around water on Mars – and what might have happened to it.

“What we thought we knew about water on Mars is constantly being put to the test,” said Michael Meyer, lead scientist for NASA’s Mars Exploration Programme. “It’s clear that the Mars of billions of years ago more closely resembled Earth than it does today. Our challenge is to figure out how this more clement Mars was even possible, and what happened to that wetter Mars.”

Strata at the base of
Curiosity has found plenty of evidence for water on the floor of Gale Crater, which likely took the form of one or more lakes during the wetter parts of Mars’ history, before becoming rivers and streams later. Strata at the foot of “mount Sharp” (shown above) strongly suggested water played a significant part in forming the mound, and the evidence for this being the case has continued to be revealed as the rover climbs the lower slopes

Currently, images of the flanks of the mound returned by the rover and from orbit suggest water-transported sedimentary deposition may have extended at least 150 to 200 metres (500 to 650 feet) above the crater floor, and possibly as high as 800 metres (approx 1/2 a mile). This both indicates that there was at least one standing body of water in the crater and further confirms that “Mount Sharp” was a direct result of sediments deposited by this water. Or at least, the lower slopes were; there is currently little evidence for the sedimentary strata extending about the 800 metre mark, however. This has led to speculation that wind-blown deposits are responsible for the upper reaches of the mound.

Taken together, the recent findings concerning Mars and its water suggest that the planet’s history is far more complex than had been thought. “We have tended to think of Mars as being simple,” John Grotzinger, the former project scientist for the Curiosity mission said of the latest findings.

“We once thought of the Earth as being simple too,” he continued. “But the more you look into it, questions come up because you’re beginning to fathom the real complexity of what we see on Mars. This is a good time to go back to re-evaluate all our assumptions. Something is missing somewhere.”

Pluto’s Water

The blue haze of Pluto's atmosphere
The blue haze of Pluto’s atmosphere: released on October 8th, this true colour image taken after the New Horizons spacecraft had completed its closest approach to the dwarf planet shows Pluto’s night side ringed by the blue haze of its thin atmosphere, as illuminated by the distant Sun, far away on the other side of the little world

The latest images and data to be received on Earth from NASA’s New Horizons space vehicle reveal Pluto’s atmosphere to be a rich blue in colour, and confirm that water ice exists on theplanet.

“Who would have expected a blue sky in the Kuiper Belt? It’s gorgeous,” said Alan Stern, New Horizons principal investigator as the striking image shown above was released as part of the latest batch of pictures and data to be received from the space craft and undergo processing and initial analysis.

The blue colour indicates that the haze within Pluto’s atmosphere is made up of a lot very fine of particulate matter, which scatters blue light from the Sun more easily than other colours, due to blue having a shorter wavelength (which is also the reason the sky we see here on Earth also appears blue, because that wavelength is easily scattered by the tiny particles making up our atmosphere).

In Pluto’s case, it’s thought that the particles in the atmosphere are largely tholins, created by ultraviolet radiation from the Sun breaking down the methane and nitrogen in Pluto’s upper atmosphere, allowing their molecules to gradually recombine into the more complex tholins, which draft down through the atmosphere, undergoing further changes, before eventually reaching the surface of the planet, giving it a distinctive reddish colour.

Instruments forming the Ralph suite aboard New Horizons have identified regions of exposed water ice on Pluto which occur in regions which have corresponding deposits of tholins. Quite what the relationship is between the two is unclear. The water ice deposits are shown in blue on the inset image simply for convience, and not because that's how they appear on Pluto
Instruments forming the Ralph suite aboard New Horizons have identified regions of exposed water ice on Pluto which occur in regions which have corresponding deposits of tholins. Quite what the relationship is between the two is unclear. The water ice deposits are shown in blue on the inset image simply for convenience, and not because that’s how they appear on Pluto

The discovery of water ice on Pluto has taken scientists by surprise. Not so much because it is there, but because it appears to be somehow related to areas of heavy tholin deposits. Confirmation of the presence of water ice came from data returned by the Ralph instrument suite aboard New Horizons, but just how widespread it might be isn’t clear, as it seems that it might be masked elsewhere by other surface material.

Continue reading “Space Sunday: of water, Apollo and space spies” →

Space Sunday: of blood moons, Mars, Pluto and Ceres

Posted on by Inara Pey
A lunar eclipse "blood moon" seen Idaho, December 2011 (image: Matt Mills / Reuters)
A lunar eclipse “blood moon” seen Idaho, December 2011 (image: Matt Mills / Reuters)

The night of Sunday 27th / Monday 28th September  promises a very special astronomical event for those fortunate enough to have clear skies overhead and are willing to stay up late (in the UK and Europe). It will see a total lunar eclipse take place at the time when the Moon reaches perigee, its closest approach to Earth in its orbit and giving rise to both a so-called “supermoon” and a “Blood Moon”.

A “supermoon” occurs when a full moon coincides with the time when the Moon is nearing its minimum distance to Earth, a distance of roughly 363,000 kilometres (226,875 miles), leading to it appearing 7-8% larger than when seen as a full Moon at other points in its orbit. A “blood moon” is the result of the Earth’s atmosphere, lying between the Sun and Moon, scatter blue light more strongly than red, so the latter reaches the Moon more strongly, giving it a reddish-brown colour when seen from Earth.

A total lunar eclipse occurs when the Sun, Earth and Moon are lined up so that th Earth is between the Sun and Moon, and the later sits within the Earth's shadow
A total lunar eclipse occurs when the Sun, Earth and Moon are lined up so that the Earth is between the Sun and Moon, and the latter sits within the Earth’s shadow (image: NASA)

Lunar eclipses are not that rare – this one will be the second of 2015, for example. However, “supermoons” are somewhat rarer. The last was in 1982, and the next will not be until 2033. So, if you want to see a really big blood moon, and you live in Western Europe, West Africa, the Eastern side of the USA and Canada or south America, then the 27th / 28th September is the night to do so. People further afield – eastern Asia, the middle east, eastern Europe and the western sides of Canada, the USA and South America will see a partial eclipse.

In the UK, the period of eclipse will start at around 01:00 BST (00:00 GMT) on the morning of Monday, 28th September, and run through until around 05:00 BST (04:00 GMT). That’s from 20:00 through to around 01:00 EDT in the USA / Canada, and 02:00 through 06:00 CET in Europe).

A total lunar eclipse and the gradual change in the Moon’s colour as seen from Earth which sees total lunar eclipses sometimes referred to as “blood moons” – the result of sunlight passing through the Earth’s atmosphere and striking the Moon’s surface (animation: Wikipedia)

The eclipse brings to a close what is referred to as a “tetrad” of total lunar eclipses – that is, four occurring “back-to-back”, with no partial eclipses between them, the first of which occurred in April 2014 and the “middle two” in October 2014 and April 2015. Some have a misguided view that this “tetrad” as being of particular significance because such events are “rare”, and this particular one started on the Passover.

However, while there can be long periods of time between occurrences of tetrads, they can also pop-up relatively frequently. For example, this century will see a total of nine tetrads occur, the first having taken place in 2003/4. Nor is the fact that this particular series started on the Passover particularly unusual; there have been eight tetrads so far coinciding with Passover since the first century AD.

So, if you are in a position to see the eclipse, you can leave the tinfoil hat on the table and step outside quite safely. Totality should occur around two hours after the eclipse starts (e.g. 03:00 BST in the UK / 04:00 CET, 22:00 EDT on the 27th September), and that’s the best time to enjoy the blood moon in all its glory.

The eclipse will also give NASA the chance to measure the full range of temperature variations during  such an event. This will be done by the Lunar Reconnaissance Orbiter (LRO), a solar-power vehicle which has been observing the Moon since 2009.

Normally during an eclipse, the LRO has most of its systems powered down to reduce the load placed on the battery systems. However, mission controllers are confident they will be able to run an instrument which will allow it to accurately measure the amount of heat loss the surface of the Moon experiences when inside the Earth’s shadow, further helping them to understand the composition of the Moon’s regolith and its function as an insulator.

Continue reading “Space Sunday: of blood moons, Mars, Pluto and Ceres” →

Space Sunday: of Pluto, Mars and crowdfunding space outreach

Posted on by Inara Pey

new-horizonNASA and the Applied Physics Laboratory (APL) at John Hopkins University kept their promise a little earlier than expected.

With the resumption of image and data transmissions from New Horizons, at the start of September, they had indicated that Fridays would henceforth, and for the course of the next 12 months, be known as Pluto Friday, the day on which the latest raw images from the mission to that distant tiny world and its companions would be released.

However, the first set of images came a little sooner than advertised: on Thursday, September 10th, and they continue to show two tiny worlds which continue to astound and have planetary scientists rethinking much about their understanding of dwarf planets.

“Pluto is showing us a diversity of landforms and complexity of process that rival anything we’ve seen in the solar system,” New Horizons’ principal investigator Alan Stern, from the Southwest Research Institute in Colorado, said in a statement. “If an artist had painted this Pluto before our flyby, I probably would have called it over the top — but that’s what is actually there.”

Charon, Pluto's largest companion, as seen by New Horizons on July 14th, 2015, from a distance of some 464,000 kilometres (290,000 miles), revealing a rich and diverse range of surface features
Charon, Pluto’s largest companion, as seen by New Horizons on July 14th, 2015, from a distance of some 464,000 kilometres (290,000 miles), revealing a rich and diverse range of surface features (image: NASA / JHU / APL / SWU) – click any image for the full-size version

The images render details as small as 400 metres / 440 yards per pixel on the surface of Pluto, and reveal features that have scientists agog with excitement; so much so that at a NASA press conference, the images were summarised thus, “it’s complicated!”

In them, we can see a rich complexity of features: nitrogen ice flows which have apparently oozed (and might still be slowly oozing) out of mountain ranges and across broad plains; mountain ranges which are themselves reminiscent of chaotic regions on Mars and Jupiter’s Europa; complex valley systems which might have been carved by the action of material flowing across the planet; and even – perhaps most curiously of all –  what seem to be wind-blown fields of dunes.

A synthetic perspective view of Pluto, based on the latest high-res received from New Horizons presents a view of Pluto from around 1,800 km (1,100 mi) above Pluto’s equatorial area. Towards the bottom of the image is the cratered and dark region dubbed "Cthulhu Regio", and above it, the bright "heart" of Pluto, showing the icy plains of "Sputnik Planum". The images used to create this view were captured from a distance of 80,000 km (50,000 mi) from Pluto
A synthetic perspective view of Pluto, based on the latest high-res received from New Horizons presents a view of Pluto from around 1,800 km (1,100 mi) above Pluto’s equatorial area. Towards the bottom of the image is the cratered and dark region dubbed “Cthulhu Regio”, and above it, the bright “heart” of Pluto, the “Tombaugh Regio”, with the icy plains of “Sputnik Planum” prominent. The images used to create this view were captured from a distance of 80,000 km (50,000 mi) from Pluto (images: NASA / JHU / APL / SWU) – click any image for the full-size version

What is also particularly striking about these images of Pluto is the way that they reveal some of the oldest  (geologically speaking) regions yet seen on the planet sitting right alongside what are the youngest locations on the planet, adding further emphasis to the idea that Pluto has been, and might still be, an active world.

But what about those dunes mentioned above? If they are indeed what the images released on September 10th suggest, Pluto has once again served up a surprise.

“Seeing dunes on Pluto, if that is what they are would be completely wild!” William McKinnon from the mission’s Geology, Geophysics and Imaging (GGI) team, said, “because Pluto’s atmosphere today is so thin. So either Pluto had a thicker atmosphere in the past, or some process we haven’t figured out is at work. It’s a head-scratcher!”

The dunes of Pluto? This image, representing a portion of Pluto's surface some 350 km (220 mi) across, shows some of the planet's older, chaotic terrain at the bottom, and an enigmatic field of dark, aligned ridges that resemble dunes which have caused planetary scientists to feel their eyebrows further vanishing under hair lines. The image was captured from a distance of 80,000 km (50,000 mi) from Pluto.
The dunes of Pluto? This image, representing a portion of Pluto’s surface some 350 km (220 mi) across, shows some of the planet’s older, chaotic terrain at the bottom, and an enigmatic field of dark, aligned ridges that resemble dunes toward the top. The image was captured from a distance of 80,000 km (50,000 mi) from Pluto (images: NASA / JHU / APL / SWU)

More is also being discovered about Pluto’s atmosphere, which is also proving to be a lot more complex than had originally been thought, having many more layers within its thin haze than had been thought. However, these layers of haze have allowed the science team to glimpse surface features which might otherwise have remained unseen as sunlight caught by the haze over the terminator – the divide between the day and night sides of the planet – cast a soft glow over part of Pluto’s night side. When enhanced through careful processing, this glow could be used to reveal what lay below.

Continue reading “Space Sunday: of Pluto, Mars and crowdfunding space outreach” →

Space Sunday: Pluto calls, Mars mystifies, Starliner prepares

Posted on by Inara Pey

new-horizonIt’s been a little quiet on the new images front where the New Horizons mission is concerned. The spacecraft, which performed the first ever flyby of Pluto and Charon in July, gathered a wealth of data, around 95% of which has remained aboard the spacecraft awaiting transmission back to Earth.

There have been a number of reasons this has been the case. First off, for the period following the close encounter, New Horizons continued to gather data and images of the Pluto-Charon system. Such is the design of the vehicle that while doing this, it couldn’t actually transmit information back to Earth. Also, once the data had been gathered it required sorting and prioritising ready for transmission back to Earth, and this again took time to do.

However, on Saturday, September 5th, New Horizons oriented itself to make contact with the Deep Space Network (DSN) operated by NASA for what was the start of a year-long “intensive” download of the 10 gigabits of data gathered by the craft, starting with information the science team regard as the highest priority data sets.

The reason the transfer will take so long is not only because the enormous distance between New Horizons and Earth, which takes radio signals moving at the speed of light over 4.5 hours to cross (a time which is slowly increasing), but also because the rate at which the data can be transmitted is limited.

Currently, the nuclear “battery” powering New Horizons can only produce around 2-10 watts of electrical power, which has to keep all of the various electrical systems warm and running. So to conserve power, the vehicle only transmits data at between 2-4 kbps. To put that in perspective, it would take you about 2 hours to download a single photo from your cellphone to your computer at those speeds.

NASA Deep Space Network facility near Canberra, Australia
NASA Deep Space Network (DSN)  is a set of three communications facilities operated by NASA in Spain, Australia (shown above) and California. They are tasked with maintaining communications with NASA’s deep space and planetary missions. Located roughly 120-degrees apart around the Earth, the three facilities can between them maintain a constant radio observation on any spacecraft under their command as the Earth rotates.

Discussing the start of the extended data download from New Horizons, Alan Stern, the mission’s Principal Investigator, said, “this is what we came for – these images, spectra and other data types that are going to help us understand the origin and the evolution of the Pluto system for the first time.”

He continued, “and what’s coming is not just the remaining 95 percent of the data that’s still aboard the spacecraft – it’s the best datasets, the highest-resolution images and spectra, the most important atmospheric datasets, and more. It’s a treasure trove.”

To mark the receipt of data and images, NASA / JPL and John Hopkins’ APL have designated Friday as Pluto Friday, when they’ll be publishing that latest images, unprocessed, received from the spacecraft the previous week. The images will be available on the LORRI image catalogue, operated by JHU / APL, starting on Friday, September 11th, 2015.

In the meantime, here’s an animated video from NASA, showing the Pluto flyby, just to whet appetites.

Mars’ Atmosphere: Where did It Go?

One of the many mysteries of Mars is what happened to its atmosphere. All of the evidence gathered over the years about the Red Planet is that it once had an atmosphere dense enough to support free-flowing liquid water, and that potentially as much of 20% of the planet’s surface may have been submerged.

So what happened? There are a number of theories. One of these is that over time, the action of the solar wind, combined with Mars’ relatively weak gravity, effectively “scooped” much of the atmosphere away into space.   Measurements of heavy and light carbon ratios in the present day atmosphere lend considerable weight to this theory.

An artist's impression of what a wet Mars may have looked like, based on the ratio of deuterium contained within the Martian polar caps
An artist’s impression of what a wet Mars may have looked like, based on the ratio of deuterium contained within the Martian polar caps

Another idea is that carbon dioxide, the major constituent of Mars’ atmosphere may have been “sequestered” – that is, “pulled” out of the atmosphere to be stored in rocks and subsurface deposits by various chemical reactions, forming carbonate minerals in the process.

This theory was given its own boost when a region of Mars called Nili Fossae, approximately as big as the US state of Arizona, was found to have huge deposits of carbonates (more recently this region has been of interest to scientists due to the discovery of impact glass, helping to mark the region as a candidate target for the Mars 2020 rover mission).

Continue reading “Space Sunday: Pluto calls, Mars mystifies, Starliner prepares” →

Space Sunday: of selfies, sprites, and black holes

Posted on by Inara Pey

CuriosityCuriosity, NASA’s Mars Science Laboratory rover has departed “Marias Pass”, a geological contact zone between different rock types on the slopes of “Mount Sharp”, some of which yielded unexpectedly high silica and hydrogen content.

As noted in a recent space update in these pages, silica  is primarily of interest to scientists, because high levels of it within rocks could indicate ideal conditions for preserving ancient organic material, if present. However, as also previously noted, it may also indicate that Mars may have had a continental crust similar to that found on Earth, potentially signifying the geological history of the two worlds was closer than previously understood. Hydrogen is of interest to scientists as it indicates water bound to minerals in the ground, further pointing to Gale Crater having once been flooded, and “Mount Sharp” itself the result of ancient water-borne sediments being laid down over repeated wet periods in the planet’s ancient past.

Curiosity actually departed “Marias Pass” on August 12th, after spending a number of weeks examining the area, including a successful drilling and sample-gathering operation at a rock dubbed “Buckskin”, where the rover also paused to take a “selfie”, which NASA released on August 19th. It is now continuing its steady climb up the slopes of “Mount Sharp.”

A low-angle self-portrait produced from multiple images captured by the Mars Hand Lens Imager (MAHLI) camera mounted on the "turret" at the end of the rover's robot arm. The images were taken on August 5th, as the rover was parked at the "Buckskin" rock formation from which it gathered drill samples
A low-angle self-portrait produced from multiple images captured by the Mars Hand Lens Imager (MAHLI) camera mounted on the “turret” at the end of the rover’s robot arm. The images were taken on August 5th, as the rover was parked at the “Buckskin” rock formation from which it gathered drill samples

As it does so, initial analysis of the first of the samples gathered from “Buckskin” is under-way. It is hoped with will help explain why the “Marias Pass” area seems to have far higher deposits of hydrogen bound in its rocks than have previously been recorded during the rover’s travels. This data has been supplied by the Dynamic Albedo of Neutrons (DAN) instrument on Curiosity, which almost continuously scans the ground over which the rover is passing to gain a chemical signature of what lies beneath it.

“The ground about 1 metre beneath the rover in this area holds three or four times as much water as the ground anywhere else Curiosity has driven during its three years on Mars,” said DAN Principal Investigator Igor Mitrofanov of Space Research Institute, Moscow, when discussing the “Marias Pass” DAN findings. Quite why this should be isn’t fully understood – hence the interest in what the drill samples undergoing analysis might reveal.

A stunning vista: the slopes of "Mount Sharp" as seen by Curiosity as it commenced the upward drive away from "Marias Pass". Captured by the rover's Mastcam systems, the image shows an intriguing landscape, with the gravel and sand ripples typical of much of the terrain over which the rover has passed in the foreground. In the middle distance sit outcrops of smooth, dust-covered bedrock, above which sit sandstone ridges. On the horizon sit rounded buttes, rich in sulfate minerals, suggesting a change in the availability of water when they formed - click image for the full size version
A stunning vista: the slopes of “Mount Sharp” as seen by Curiosity as it commenced the upward drive away from “Marias Pass”. Captured by the rover’s Mastcam systems, the image shows an intriguing landscape, with the gravel and sand ripples typical of much of the terrain over which the rover has passed in the foreground. In the middle distance sit outcrops of smooth, dust-covered bedrock, above which sit sandstone ridges. On the horizon sit rounded buttes, rich in sulfate minerals, suggesting a change in the availability of water when they formed – click image for the full size version

The drilling operation itself marked the first time use of the system since a series of transient short circuits occurred in the hammer / vibration mechanism in February 2015. While no clear-cut cause for the shorts was identified, new fault protection routines were uploaded to the rover in the hope that should similar shorts occur in the future, they will not threaten any of Curiosity’s systems.

A Flight over Mars

With all the attention Curiosity gets, it is sometimes easy to forget there are other vehicles in operation on and around Mars which are also returning incredible images and amounts of data as well – and were doing so long before Curiosity arrived.

One of these is Europe’s Mars Express, the capabilities of which come close to matching those of NASA’s Mars Reconnaissance Orbiter. Mars Express has been in operation around Mars for over a decade, and in that time has collected an incredible amount of data.

At the start of August, ESA released a video made of high resolution images captured by the orbiter of the Atlantis Choas region of Mars. This is an area about 170 kilometres long and 145 wide (roughly 106 x 91 miles) comprising multiple terrain types and impact craters, thought to be the eroded remnants of a once continuous ancient plateau. While the vertical elevations and depressions have been exaggerated (a process which helps scientists to better understand surface features when imaged at different angles from orbit), the video does much to reveal the “magnificent desolation” that is the beauty of Mars.

Continue reading “Space Sunday: of selfies, sprites, and black holes” →

Space Sunday: active Ceres, open Mars, and shooting stars

Posted on by Inara Pey

Dawn mission patch (NASA / JPL)Dawn, the NASA / ESA joint mission to explore two of the solar system’s three “protoplanets” located in the asteroid belt between the orbits of Mars and Jupiter, continues to intrigue scientists as it studies Ceres, the second of its primary targets.

As I reported in June 2015, Dawn is part of a broader effort to better understand the origins of the solar system and how the planets actually formed; all of which might give us greater understanding of how life arose here on Earth.

Launched in September 2007, Dawn arrived at Ceres in March 2015, after a 2.5 year transit flight from Vesta, its first destination, which it had been studying for 14 months following its arrival in July 2011. Because of their relative size – Ceres accounts for around one-third of the total mass of the asteroid belt – both of these airless, rocky bodies are regarded as dwarf planets, rather than “simple” asteroids. However, Ceres is proving to be quite the conundrum.

At the start of July, Dawn completed the first part of its high-altitude survey of Ceres and fired its low-thrust ion drive to start a series of gentle manoeuvres to reduce its orbit around from 4,400 kilometres (2,700 miles) to 1,450 kilometres (900 miles). It’s now hoped that from this lower orbit, the space craft will be able to discover more about some of Ceres’ more mysterious features.

One in particular has been the subject of much debate. It started when Dawn imaged a series of bright spots within the crater Occator as it made its initial loop around Ceres to enter orbit. Since that time, it has repeatedly images the bright spots, and their presence has also been confirmed by the Hubble Space Telescope.

A June 6th image of the bright spots within a crater on Ceres, captured by Dawn on June 6th, 2015, from a distance of
A Dawn spacecraft image of the bright spots within a crater on Ceres, captured on June 6th, 2015. With the vehicle now entering a much lower altitude mapping mission, it is hoped that even more detail on the spots  – and the faint haze discovered within the crater – will be obtained

Currently, it is believed the bright marks might either be salt deposits or water ice (the European  Herschel Space Observatory had previously found evidence of water vapour on Ceres).  However, while the science team aren’t leaning either way, their mission briefing on July 21st, leant some weight to the bright spots perhaps being water ice. This came in the form of an announcement that he 92 kilometre (57 mile) wide Occator has its own, very localised atmosphere focused around the bright areas.

The evidence for this comes from images of the crater taken from certain angles which reveal a thin haze covering around half of the cater, but not extending beyond its walls. Th thinking is that this haze is perhaps the result of the ice in the bright area – if they are ice – sublimating out.

However, if this is the case, it actually raises a further mystery: why the haze? Generally, such sublimation would lead to the resulting gases dissipating very quickly, without forming a haze. One hypothesis is that Ceres’ gravity, which is somewhat higher than might be expected for a body of its size) may be and influencing factor.

The 5 km high "pyramid" mountain pokes up above the limb of Ceres. Flat-topped, it has streaks of bight mateiral on its flanks giving the impression something has been flowing down it.
The 5 km high “pyramid” mountain pokes up above the limb of Ceres. Flat-topped, it has streaks of bright material on its flanks giving the impression something has been flowing down it.

The bright spots aren’t the only curious feature on Ceres. Dawn has also spotted numerous long, linear features whose cause is unknown, as well as one big mountain that mission team members have dubbed “The Pyramid.” This massif, about 5 km (3 mi) in height, and around 30 km (19 mi) across at its base, is oddly flat-topped and has streaks of bright material on one of it flanks, as if something has been cascading down the slope. What this might indicate has planetary scientists scratching their heads at this point.

With all the mysteries thrown up by New Horizon’s recently flyby of Pluto, and Dawn’s discovery of mysterious features on Ceres, it really is becoming a case that the tiny worlds of our solar system are perhaps the most perplexing.

Three years ago, in August 2012, NASA’s Mars Science Laboratory rover, Curiosity, arrived in Gale Crater, Mars. Since that time, the rover has made some remarkable discoveries, as reported in this blog over the years.

To mark the anniversary of the landing, NASA has launched two new on-line tools designed to open the mysterious terrain of the Red Planet to anyone with an interest in planetary exploration.

Experience Curiosity allows users to journey along with the one-tonne rover on its Martian expeditions. The program simulates Mars in 3-D, using actual data returned by the rover and NASA’s Mars Reconnaissance Orbiter (MRO). It also uses a  game-ready rover model based entirely on real mechanisms.

Experience Curiosity allows you to learn about the rover using a 3D model which can be manipulated and driven, using a WebGL application
Experience Curiosity allows you to learn about the rover using a 3D model which can be manipulated and driven, using a WebGL application

User are able to drive the rover, examine it, call up data on key components, witness the driving view from different cameras on the rover, and operated the robot arm. Activities are a little basic, but as this appears to be a part of NASA’s Eyes On project, capabilities may grow over time.

Mars Trek is a much more expansive tool – one which is actually being used in the planning for the Mars 2020 rover mission. It features interactive maps, which include the ability to overlay a range of data sets generated from instruments aboard spacecraft orbiting Mars, and analysis tools for measuring surface features. Standard keyboard gaming controls are used to manoeuvre the user across Mars’ surface, and topographic data can be exported to 3D printers to allow the printing of physical models of surface features.

The map view and be manipulated in 2D or 3D, data on various surface missions is provided, compete with the ability to zoom into the surface locations for these missions, making for a visually impressive model.

Continue reading “Space Sunday: active Ceres, open Mars, and shooting stars” →