Tag: Spaceflight

Space Sunday: BEAM and Kepler, Europa and comets

Posted on by Inara Pey
Euorpa's icy, mineral-stained surface as imaged by NASA's Galileo mission - see bwlow (credit: NASA / JPL)
Euorpa’s icy, mineral-stained surface as imaged by NASA’s Galileo mission – see below (credit: NASA / JPL)

In my last Space Sunday article, I covered the arrival of the BEAM inflatable module at the International Space Station, and the concerns for NASA’s Kepler “planet hunter” space observatory. As there’s been further news on both of these, I thought I’d start this Space Sunday with a quick round-up on them, starting with Kepler.

The Kepler observatory, located some 121 million kilometres (75 million miles) “behind” Earth as both orbit the Sun, has been engaged in a 7-year mission to try to locate planets – particularly possible Earth-type planets – orbiting other stars. As I reported last time around, despite one major setback which called a halt to the observatory’s primary mission in 2012, Kepler has been a remarkably successful mission, catalogue some 4,000 potential planets orbiting other suns, with over 1,000 subsequently confirmed as planets.

However, on April 7th, Kepler reported to mission managers that it has entered Emergency Mode – a status indicating a critical problem has occurred, causing the observatory to shut down all science operations and other systems, and was utilising its supplies of valuable propellant to maintain its orientation so it could communicate with Earth, rather than using its electric reaction wheels, powered by sunlight.

Keler 425b - the first Earth-like planet to be found orbiting within its sun's habitable zone
Keler 425b – the first Earth-like planet to be found orbiting within its sun’s habitable zone (credit: NASA)

Over the next several days, mission engineers were able to upload instructions to Kepler so that it could position itself in a “point rest state” where communications could be maintained without eating into further propellant reserves. Following this, a long, slow data download commenced, which allowed engineers to fully understand the extent of the problem – but not the cause. However, this has been enough for a path to recovery to be determined.

Kpler: being nursed back to health from 121 million km away
Kpler: being nursed back to health from 121 million km away (credit: NASA)

Since April 12th, commands have been sent to the observatory instructing it to bring it non-critical systems back on-line one at a time, monitoring responses as it did so. With each system successfully restored, Kepler has been gradually coming to life whilst eliminating potential causes of the original problem. There is still a way to go, but mission managers are now reasonably confident Kepler can be restored to a fully operational status.

“The recovery started slowly and carefully, as we initially merely tried to understand the situation and recover the systems least likely to have been the cause,” said Kepler programme manager Charlie Sobeck on April 14th. “Over the last day and a half, we’ve begun to turn the corner, by powering on more suspect components. With just one more to go, I expect that we will soon be on the home stretch and picking up speed towards returning to normal science operations.”

Meanwhile, BEAM – the Bigelow Expandable Activity Module – an inflatable prototype habitat module which arrived at the International Space Station on April 10th – was extracted from its ferry vehicle, the uncrewed Dragon resupply vehicle, on Saturday April 16th, and successfully secured against the airlock node of one of the station’s modules.

the extraction and relocation were undertaken remotely, using the space station’s robot arm commanded from Earth to lift the BEAM unit, still in its compact “flight” configuration just 2.4 metres (8ft) in length and 2.1 metres (7ft) diameter, from the unpressurised section of the Dragon cargo vehicle and then position it against the US Tranquillity Module of the space station, where it was secured by astronauts Tim Kopra and Jeff Williams.

Space station commander Tim Kopra took this photograph of the BEAM unit, in its compact state, being moved towards the Tranquillity module by the station's robot arm, ready for it to be secured against one of the station's airlocks
Space station commander Tim Kopra took this photograph of the BEAM unit, in its compact state, being moved towards the Tranquillity module (seen on the left, directly under the robot arm) by the station’s robot arm, ready for it to be secured against one of the station’s airlocks (credit: NASA / Tim Kopra)

The module is not due to be inflated until early May, when it will increase in size to some 4m x 3.5m (13ft x 10.5ft) and provide some 16 cubic metres (565 cubic ft) of working space. It will be equipped with monitoring equipment  to investigate how well it protects against solar radiation, space debris and contamination over a 12-18 month period. During this time, ISS crew members will enter the unit 3 or 4 times a year to collect deployment dynamics sensor data, perform microbial surface sampling, conduct periodic change-out of the radiation area monitors, and inspect the general condition of the module.

BEAM-animation
Animation showing the manoeuvre to position BEAM against the Tranquillity module

Continue reading “Space Sunday: BEAM and Kepler, Europa and comets” →

Space Sunday: Of Odysseys, rockets, inflatables and exoplanets

Posted on by Inara Pey
Mars Odyssey: 15 years since launch and still going strong
Mars Odyssey: 15 years since launch and still going strong

Fifteen years ago, on April 7th, 2001, NASA launched their Odyssey mission to Mars. Since then, this orbital vehicle, whilst often overlooking in favour of its younger companions, Mars Express from Europe and NASA’s Mars Reconnaissance Orbiter, has done much to revolutionise our understanding of Mars.

Named for 2001: A Space Odyssey, the seminal science-fiction novel by Arthur C. Clarke, Odyssey arrived in orbit around Mars in October 2001. In doing so, not only did it overcome the failures of the 1999 Mars Climate Orbiter and Mars Polar Lander missions, it almost immediately scored its own major success: one suite of instruments found evidence for water ice close to the surface in large areas of Mars – as significant finding which has since gone on to shape much of our thinking about what lies within the Martian crust.

In 2010, Odyssey provided the highest-resolution (at that time) global map of Mars, stitched together from 21,000 images returned by the Thermal Emission Imaging System (THEMIS). Prior to that, in 2008 Odyssey spotted evidence of salt deposits across about 200 places in the south of Mars. NASA considers these areas to be signs of where abundant water used to sit. Scientists theorized the deposits could come from groundwater, which evaporated and left deposits of mineral behind. While in 2007, Odyssey imaged what appeared to be massive cave mouths on the surface of Mars.

THEMIS confirmed the openings – each between 100 to 250 meters (328 to 820 feet) across – were either vertical shafts running into the Martian crust or possibly openings leading to cavernous spaces beneath the surface. Dubbed the “seven Sisters” the openings were discovered on the flank of Arsia Mons, one of the gigantic Tharsis volcanoes, prompting speculation that they might be the collapsed roofs of lava tunnels within the volcano’s slopes.

A 2007 THEMIS image from Mars Odyssey showing entrances to possible Martian caves, dubbed the "seven sisters." Clockwise from upper-left: Dena, Chloe, Wendy, Annie, Abbey, Nikki and Jeanne. Arrows signify direction of solar illumination (I) and direction of North (N) - Credit: GE Cushing, TN Titus, JJ Wynne, USGS, USGS, Northern Arizona University, and PR Christensen of Arizona State University
A 2007 THEMIS image from Mars Odyssey showing entrances to possible Martian caves, dubbed the “seven sisters.” Clockwise from upper-left: Dena, Chloe, Wendy, Annie, Abbey, Nikki and Jeanne. Arrows signify direction of solar illumination (I) and direction of North (N) – Credit: GE Cushing, TN Titus, JJ Wynne, USGS, USGS, Northern Arizona University, and PR Christensen of Arizona State University

The vehicle has also operated in concert with the Mars Reconnaissance Orbiter in support of surface missions, including both the Curiosity and Opportunity rovers. As well as acting as a communications relay for such missions, Odyssey has been able to add context to the rovers’ work by providing thermal and other images which have helped science teams better understand the environments in which the rovers are operating. Nor does it end there. Odyssey has also been a careful observer of the Martian weather.

As each year on Mars lasts around 26 months, Odyssey has observed the planet through more than six Martian years. These observations have revealed some seasonal patterns that repeat each year and other seasonal events, such as large dust storms, which differ significantly from year to year.

A 2001 false colour map of Mars made from data gathered by Odyssey's gamma ray spectrometer reveals the widespread distribution of hydrogen-enriched soil on Mars (in blue), the result of sub-surface ice deposits
A 2001 false colour map of Mars made from data gathered by Odyssey’s gamma ray spectrometer reveals the widespread distribution of hydrogen-enriched soil on Mars (in blue), the result of sub-surface ice deposits

In just this past year, Odyssey’s orbit has put the spacecraft in position to observe Mars in early morning light. Previously, the spacecraft flew over ground that was either in afternoon lighting or pre-dawn darkness. The new orbit enables studies of morning clouds and fogs and comparison of ground temperatures in the morning to temperatures of the same sites in the afternoon and pre-dawn, again helping to increase our understanding of the various atmospheric mechanisms operating on the planet.

With 15 years under its belt, Odyssey continued to work hard around Mars and shows no sign of stopping. So, happy anniversary, Odyssey!

On Land and Sea

Hard on the heels of Blue Origin’s third successful launch and recovery of their sub-orbital New Shephard capsule and propulsion module during a test flight, Elon Musk’s SpaceX has achieved what had been eluding them:  launching a Falcon 9 rocket with a payload bound for the International Space Station and then landing the first stage of the rocket on a platform at sea.

The success comes after four prior attempted to land the first stage of the booster at sea – part of SpaceX’s efforts to develop a semi-reusable system to reduce overall launch costs – all ended with the booster crashing into the floating landing platform, or toppling over post touch-down.

The Falcon 9 1.1 furst stage of CRS-8 stands tall on the the drone ship following its landing on April 8th, 2016
The Falcon 9 1.1 furst stage of CRS-8 stands tall on the drone ship Of Course I Still Love You, following its landing on April 8th, 2016 (credit: SpaceX)

The April 8th launch, officially titled CRS-8, lifted-off from Cape Canaveral Air Force Station, Florida, at 8:53 GMT. After separating from the second stage of the rocket, which carrying the Dragon cargo craft up to orbit, the first stage of the booster performed a series of three burns  to slow it down and boost it back towards the landing platform – referred to as an autonomous drone ship – that was keeping station downrange of the launch site. Eight and a half minutes after the launch, the first stage made a vertical descent over the platform, re-firing its main engines to slow itself as the landing legs deployed from along the side of the rocket’s body, and it eased into a gentle touch-down.

After the landing, crew boarded the platform to weld the rocket’s landing pads to the deck as a precaution against it toppling over while the platform was being towed back to port. Current plans call for the platform to undergo examination and testing at Kennedy Space Centre to ensure no structural damage occurred during the landing, before it is refurbished for a further at-sea landing, possibly in June 2016. The Falcon booster stage will  also undergo post-flight examination prior to being refurbished for a future launch.

Continue reading “Space Sunday: Of Odysseys, rockets, inflatables and exoplanets” →

Space Sunday: of rockets, rovers and impacts

Posted on by Inara Pey
Blue Origin's New Shephard lifts-off on Saturday, April 2nd on a successful sub-orbital test flight which saw both capsule and propulsion module successfully recovered
Blue Origin’s New Shephard lifts-off on Saturday, April 2nd on a successful sub-orbital test flight which saw both capsule and propulsion module successfully recovered

Blue Origin, established by  Amazon founder Jeff Bezos, scored a three-for-three with launches and landings of their sub-orbital New Shephard launch vehicle.

Intended to offer passengers the opportunity to experience the microgravity of space, New Shephard is a two stage vehicle comprising the capsule unit which will eventually carry  6 people to the each of space, and a rocket stage simply called the “propulsion module”. Both are designed to be fully re-usable in order to reduce the overall cost of launch operations.

The Blue Origin propulsion module just a couple of seconds from touch down on April 2nd, 2016 (image: Blue Origins)
The Blue Origin propulsion module just a couple of seconds from touch down on April 2nd, 2016 (image: Blue Origins)

Having first flown on November 23rd, 2015, when the capsule unit reached an altitude of 100.5 km (63 mi) before parachuting back to a soft landing and the propulsion module made a powered descent and landing, the April 2nd, 2016, marked the third successful flight for both capsule and propulsion module, the latter now having been used for all three successful flights in November 2015, January 2016 and April 2016.

During the flight, the capsule – which was carrying a small science payload – reached a maximum altitude of 103.4 km (64.4 mi) before making a return to Earth under its parachutes, while the propulsion module steered its way back to the launch site to make a powered landing.

Nor was this a run-of-the-mill return for the propulsion module, as a the ascent / descent engine was re-lit at a much higher altitude that is expected during operational flights, at around 1,107 metres (3,600 ft), in a manoeuvre designed to further test the engine’s reliability and the wear and tear it might suffer during a flight. Understanding both of these factors will help Blue Origin better identify the overall costs involved in refurbishing rocket and engines between flights.

The New Shephard capsule, whilst primarily intended to fly people on sub-orbital flights, can also be used for science research, as demonstrated in this flight, which saw the capsule carry the Box of Rocks experiment from the Southwest Research Institute, designed to explore how rocky debris settles in microgravity, and the University of Central Florida’s Collisions into Dust experiment, which aims to better understand how large bodies interacted with dust in the early Solar System.

The New Shephard capsule being recovered following its parachute landing (image: Blue Origin)
The New Shephard capsule being recovered following its parachute landing (image: Blue Origin)

While Blue Origin appear to be slightly ahead of SpaceX in terms of launching and recovering their rockets, it’s important to remember that the current New Shephard vehicle and the SpaceX Falcon 1.1 are very different beasts. Not only is the latter some 3 times bigger than New Shepard, the first stage of the vehicle flies much higher and faster than the Blue Origin vehicle, both of which make returning the first stage of the booster to a landing site to make a safe touchdown far more of a technical challenge.

That said, the sub-orbital capabilities of New Shephard are only one phase of Blue Origin’s plans. With the vehicle expected to commence crewed test flights in 2017 and offer sub-orbital tourist flights from 2018, the company plan to gradually uprate the vehicle to a point were it will also be able to undertake orbital launches and still be recovered.

Walking with Rovers

NASA is continuing to ramp public interest in Mars, with a new public outreach programme set to begin in summer 2016.

Destination: Mars builds on the ongoing cooperative work between the space agency and Microsoft in developing applications and opportunities for the Miscrosoft HoloLens system. As I’ve previously reported, NASA is already using the HoloLen aboard the International Space Station, and have also developed a means for members of the Curiosity science team put themselves “on” Mars using the HoloLens and data / images returned by the rover.

It is in the latter capacity that Destination: Mars is designed to work, offering the public, using the mixed reality capabilities of the HoloLens to “visit” Mars.

Apollo 11 Lunar Module Pilot and second man on the Moon, Edwin "Buzz" Aldrin, acts as a virtual host for Destination: Mars
Apollo 11 Lunar Module Pilot and second man on the Moon, Edwin “Buzz” Aldrin, acts as a virtual host for Destination: Mars

Continue reading “Space Sunday: of rockets, rovers and impacts” →

Space Sunday: of ice and salts, aurorae, and mountains

Posted on by Inara Pey
A true colour image returned by the Dawn space probe of one of the bright "spots" in Occator crater on Ceres, revealing what might be a cryo-volcano
A true colour image returned by the Dawn space probe of one of the bright “spots” in Occator crater on Ceres, revealing what might be a cryovolcano (credit:NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI)

The science team behind the joint NASA / ESA Dawn mission has released the most stunning high-resolution images yet seen of Ceres, one of the solar system’s three “protoplanets” located in the asteroid belt between the orbits of Mars and Jupiter.

The Dawn spacecraft has been mapping Ceres for also a year, operating at its lowest altitude above the tiny world since December 2015. During the course of the year, the images and data it has returned have, alongside information sent to us about Pluto and Charon by the New Horizons mission, caused planetary scientists to start seriously reconsidering all they thought they understood about minor planetary bodies in the solar system.

However, one thing everyone has been waiting for has been to see high-resolution images of Occator crater and the strange bright spots within it which have been the cause of so much interest and speculation, ever since they were first imaged by the Hubble Space Telescope.

A false-colour image showing the main peak in Occator crater with the small bright spots off to the right
A false-colour image showing the main peak in Occator crater with the small bright spots off to the right (credit:NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI)

While the vehicle may have commenced its most detailed mapping orbit of Ceres in December, due to the complexities of Dawn’s orbit around the tiny world, it was not until relatively recently that it was able to overfly the 92 km (57 mi) diameter Occator and capture images of what lay within it, and these images were released on March 22nd, as a part of a science briefing given at the 7th annual Lunar and Planetary Science Conference in Texas.

Taken from an altitude of just 385 kilometres (240 miles) above the crater, the images reveal a huge dome-like structure with a dimpled top forming the brightest of the “spots” in Occator. It looks for all the world like a volcano, prompting speculation that it might be what is called a “cryovolcano”. The theory here being that Ceres may contain significant quantities of volatiles (ices), which are gently heated by the dwarf planet’s interior, causing them to erupt through the surface layer, the deposits they leave behind slowly building up the volcano-like dome.

A false colour elliptical map of Ceres showing that Occator (just right of centre) is not the only bright spot on the tiny planetoid others, mostly associated with young (around 70-150 million years old) craters
A false colour elliptical map of Ceres showing that Occator (just right of centre) is not the only bright spot on the tiny planetoid others, mostly associated with young (around 70-150 million years old) craters (credit:NASA / JPL-Caltech / UCLA / MPS / DLR / IDA / PSI)

However, this is not he only theory on what might be happening. Spectral observations show that the light patches found in Occator and elsewhere are consistent with a magnesium sulphate called hexahydrite, which resembles Epsom salts here on Earth. Thus, an alternative theory is that impacts in places like Occator expose the salt-rich ices trapped in the crust to the vacuum of space. This causes the ice to sublimate (vaporise), leaving the salt behind.

Commenting on the two the two theories, Ralf Jaumann, planetary scientist and Dawn co-investigator at the German Aerospace Center (DLR) said, “Before Dawn began its intensive observations of Ceres last year, Occator Crater looked to be one large bright area. Now, with the latest close views, we can see complex features that provide new mysteries to investigate. The intricate geometry of the crater interior suggests geologic activity in the recent past, but we will need to complete detailed geologic mapping of the crater in order to test hypotheses for its formation.”

In the interim, NASA has released a new video summarising Dawn’s investigations of Ceres.

Cygnus Rendezvous with ISS

March 22nd saw the latest Orbital ATK Cygnus resupply vehicle lifted-off from Space Launch Complex 41 on Cape Canaveral Air Force Station, Florida in a spectacular night-time launch beneath a full Moon.

The automated vehicle, carrying 3.5 tonnes of supplies and equipment up to the International Space Station, made a flawless ascent into the Florida sky, the clear weather and moonlight offer some extraordinary opportunities for photographers, as shown in the image below, taken by Alex Polimeni for Spaceflight Now.

Long exposure photograph shows the trail of the Atlas V launch vehicle as it carries the Cygnus OA6 vehicle "Rick Husband" into orbit on March 22nd, 2016. In the foreground is the world famous Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Centre (credit: Alex Polimeni / Spaceflight Now)
Long exposure photograph shows the trail of the Atlas V launch vehicle as it carries the Cygnus OA6 vehicle “Rick Husband” into orbit on March 22nd, 2016. In the foreground is the world-famous Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Centre (credit: Alex Polimeni / Spaceflight Now)

Continue reading “Space Sunday: of ice and salts, aurorae, and mountains” →

Space Sunday: the Martian tilt and Plutonian clouds

Posted on by Inara Pey
Tethys, Enceladus and Mimas seen above and blow Saturn's rings in a stunning image captured by the NASA / ESA Cassini mission, released on February 22nd, 2016. - are captured in this group photo from NASA's Cassini spacecraft released on Feb. 22. Tethys (660 miles across) appears above the rings, while Enceladus (313 miles across) sits just below center. Mimas (246 miles across) hangs below and to the left of Enceladus. This view looks toward the sunlit side of the rings and was acquired at a distance of approximately 837,000 miles from Enceladus.
Tethys, Enceladus and Mimas seen above and blow Saturn’s rings in a stunning image captured by the NASA / ESA Cassini mission, released on February 22nd, 2016. Tethys, 1056 km (660 mi) in diameter appears above the rings, with  Enceladus, 501 km (313 mi) across, just below them with Mimas, 393.6 km (246 mi) across below and to the left of Enceladus. Looking towards the sunlit side of the rings and was acquired at a distance of approx 1,339,000 km (837,000 mi) from Enceladus (credit: NASA / JPL)

The Sliding Surface of Mars

We’re all familiar with images of the surface of Mars, with the Tharsis volcanoes straddling the equator and the great gash of the Vallis Marineris just to the south. It’s a view seen in many orbital images of the planet, and one thought to have been more-or-less representative of the topography of Mars from the earliest times.

However, new studies by geomorphologists, geophysicists and climatologists led by a team of French scientists, suggest that the surface of the planet underwent a gigantic “tilt” of between 20 to 25 degrees some 3 to 3.5 billion years ago, drastically altering its appearance whilst also offering an explanation for one of the mysteries of Mars.

Mars as we know it today, Arsia Mons, Pavonis Mons, and Ascraeus Mons straddling the equator
Mars as we know it today, Arsia Mons, Pavonis Mons, and Ascraeus Mons straddling the equator, and part of the Tharsis Bulge, with massive Olympus Mons further to the north and west, and the gash of the Vallis Marineris to the south and east

While a process known as variations of obliquity can cause a planet’s axial tilt to shift  over large periods of time (Earth’s axial tilt of 23.4° is decreasing at the rate of about 47 minutes of arc per century, for example), this is not the cause of Mars’ shifting “face”. Rather it is the result of the massive Tharsis Bulge.

The largest volcanic dome in the solar system, Tharsis is a plateau some 5,000 km (3,125 mi) across and around 12 km (7.5 mi) thick, topped by the massive volcanoes of Tharis Montes: Arsia Mons, Pavonis Mons, and Ascraeus Mons. It formed over a period of roughly half a billion to a billion years, commencing around 3.7 billion years ago.

The French research suggests that as the Tharsis Bulge grew as a result of volcanic activity, so it gained considerable mass – perhaps a billion billion tonnes), which caused the crust and mantle of the planet to “slip” around the core, rather like turning the flesh of an apricot around its stone. Thus, Tharsis appears to have “dropped” to the equator from a latitude of around 20 degrees north, completely changing the face of Mars during its first 1 to 1.5 billion years of history – the time at which life might have arisen, if it arose at all.

Mars as it may have appeared around 3.5-3.7 years ago, prior to the Tharsis Bulge forming
Mars as it may have appeared around 3.5-3.7 years ago, prior to the Tharsis Bulge forming (credit: Didier Florentz, Université Paris-Sud)

While such a slippage had previously been suggested, notably through the work of Isamu Matsuyama of the University of Arizona in 2010, the French study is the first to offer definitive geomorphological evidence that this is the case. One of the major outcomes of the work is that it explains why Mars has huge and seemingly anomalous underground reservoirs of water ice located far from the poles. As the mantle and crust shifted, so they carried the frozen land which originally lay over the poles away from them, complete with the subsurface water and ice.

Overall, the study radically alters the generally accepted chronology of Mars, which has Tharsis forming before the before the widespread creation of rivers and water channels on Mars. now it appears that Tharsis formed at a time congruent with the existence of liquid water on Mars and the formation of river valleys and other water features. Thus, the volcanic activity on Tharsis may have actually contributed to the period of liquid stability on the planet.

The Methane Snows and Particle Clouds of Pluto

enhanced color image is about 2,230 feet (680 meters) per pixel. The image measures approximately 280 miles (450 kilometers) long by 140 miles (225 kilometers) wide. It was obtained by New Horizons at a range of approximately 21,100 miles (33,900 kilometers) from Pluto, about 45 minutes before the spacecraft’s closest approach to Pluto on July 14, 2015.
Captured from a distance of 33,900 km (21,000 mi) from the point of closest approach to Pluto on July 14th, 2015, this New Horizons enhanced colour image reveals the ice-capped mountains of “Cthulhu Regio” in a strip some 450 x 225 km (280 x 140 mi). The image was taken about 45 minutes prior to closest approach (NASA/JPL / DHU?APL / SwRI)

The New Horizons team has discovered a chain of exotic snowcapped mountains stretching across the dark expanse on Pluto informally named “Cthulhu Regio”, one of the minor planet’s more identifiable features, and which stretches almost halfway around Pluto equator, some 3,000 km (1,850 mi) in length and some 750 km (450 mi) across, with one end abutting the ice-covered flats of “Sputnik Planum” I’ve previously written about in my coverage of New Horizons.

The high-resolution images show a mountain range in approximately 420 km ( 260 mi) long, the highest slopes of which are coated with a bright material that contrasts sharply with the dark red of the more usual dark red colouring of the region (thought to be the result of dark tholins, complex molecules initially formed by the reaction of methane and sunlight high in Pluto’s atmosphere, coating much of “Cthulhu Regio”. Scientists believe the white material could be methane which has condensed out of Pluto’s tenuous atmosphere to form ice, coating the peaks, much as ice can condense out of cold air on Earth to form frost. There has even been speculation that the white material is the result of methane ice condensing as “snow” and falling across the peaks.

Continue reading “Space Sunday: the Martian tilt and Plutonian clouds” →

Space Sunday: Martian “coral”, Planet Nine and Dream Chasers

Posted on by Inara Pey
The MER rovers first arrived on Mars at the start of 2004. One, Opportunity, is still operating today
The MER rovers first arrived on Mars at the start of 2004. One, Opportunity, is still operating today (credit: NASA / JPL)

Spirit, one of NASA’s two solar-powered Mars Exploration Rover (MER) missions, may have ceased communications with Earth on March 22nd, 2010 and the mission declared over on May 24th, 2011, but its science legacy lives on.

Originally designed with a 90-day primary mission duration, Spirit massively exceeded this, ranging across Mars for a distance of 7.73 kilometres (4.8 mi) over 1,944 days of mobile operations before becoming bogged down in a sand trap on May 1st, 2009, almost 5.5 years after it had arrived on Mars, after which it operated as a stationary research programme for a further 751 days.

During its mobile period, Spirit explored a small rocky plateau dubbed “Home Plate” in 2007 / 2008. Whilst exploring the rock, the rover imaged several peculiar small rock formations resembling cauliflower or coral.  Analysis by the rover’s Mini-Thermal Emission Spectrometer (Mini-TES) revealed the formations to be almost pure silica (SiO2), a mineral associated with volcanic environments.

Silica is formed when water (rain or snow) seeps underground and comes into contact with rocks heated from below by magma. Itself super-heated by the rocks, the water is vaporised and rises back through the ground, dissolving silica and other minerals as it does so, which it deposits around the vents or fumaroles it uses to escape back into the atmosphere.

the "cauliflower" or "coral" formations imaged by MER rover Spirit around the "home Plate" plateau in 2008
the “cauliflower” or “coral” formations imaged by MER rover Spirit around the “home Plate” plateau in 2008 (credit: NASA / JPL)

Warm, rich in silica and minerals, on Earth these fumaroles and vents become havens for bacterial life which is known for creating curious bulbous and branching shapes in silica formations here on Earth which are strikingly similar to those imaged by Spirit. Such is the similarity, that planetary geologist Steven Ruff and geology professor Jack Farmer, both from Arizona State University, have been carrying out detailed studies in the high Atacama Desert, regarded as the most arid non-polar region on Earth, harbouring conditions thought to be very similar to those of ancient Mars.

In particular, they have been investigating the remote geyser fields of El Tatio, some 4.3 km  above mean sea level in an environment which has much in common with the Gusev Crater region of Mars, where “Home Plate” resides. This includes being exposed to high levels of ultraviolet light from the sun and extreme temperatures.  Their investigations revealed forms they call “micro-digitate silica structures” which are both remarkably similar to the formations on Mars, and to those found around fumaroles and vents at lower altitudes here on Earth which are formed by bacteria.

A comparison between images of the formations found on Mars by the MER Spirit (top right), and those images by Ruff and Foster in El titio, Atacama Desert
A comparison between images of the formations found on Mars by the MER Spirit (top right), and those imaged by Ruff and Foster in El Tatio, Atacama Desert (credit: S. Ruff, Arizona State University)

While the pair have yet to come up with definitive evidence that the El Tatio formations are the result of microbial activity, they believe the objects may be “micro-stromatolites”.  Nornally of a much larger size, stromatolites are formed by bacteria “cementing” mineral grains together to form a thin layer. Over time, these layers accumulate one over the last, forming a laminar mound or rock. The oldest stromatolites on Earth are estimated to be some 3.5 billion years old, a time when both Earth an Mars may have shared much closer atmospheric and geological similarities. So, if the formations found at El Tatio do prove to be the result of bacterial activity, then it offers a hypothesis that the formations on Mars may also have been the result of bacterial activity.

Dream Chaser: the Dream is Alive

In January, I wrote about NASA’s surprise decision to award an extended contract for uncrewed resupply missions to  the International Space Station to both of the existing contract holders, SpaceX and Orbital ATK, and to Sierra Nevada Corporation, who will use an uncrewed variant of their Dream Chaser space plane.  At the time I wrote that update, reader Devin  Vaughn indicated an interest in learning more about Dream Chaser, which has an interesting heritage.

As I noted at the time, the vehicle had been one of four private sector contenders to fulfil the role of “space taxi”, ferrying up to 6 at a time from US soil to the ISS. The idea being that by spinning-out the ISS crewed flights to the private sector (with financial support from NASA), the US agency could focus its manned space flight development programme solely on the Orion / SLS programme, which is intended to form the nucleus of US (and possibly international) crewed mission ventures well beyond Earth orbit.

Dream Chaser was unique among the commercial crew transportation proposals as it was based on a "lifting body" design , allowing to re-enter the Earth's atmosphere and glide to a landing on a conventional runway - aspects which still make it a very flexible vehicle
Dream Chaser was unique among the commercial crew transportation proposals as it was based on a “lifting body” design , allowing to re-enter the Earth’s atmosphere and glide to a landing on a conventional runway – aspects which still make it a very flexible vehicle (credit: SNC)

Dream Chaser ultimately wasn’t selected for the crewed mission contract – which caused some friction between Sierra Nevada Corporation and NASA when it was announced in 2014 – but the US space agency continued to work with SNC to help develop the vehicle,  with the Dream Chaser Cargo variant being the result – although SNC has not given up on developed the crewed version of the vehicle.

Dream Chaser Cargo is designed to fly up to 5 tonnes of cargo to / from orbit. This can be both pressurised and unpressurised material, and the vehicle includes the ability for unpressurised cargo to be directly transferred from its cargo module to the exterior of the space station should this be required. As with the original crewed variant, Dream Chaser Cargo will launch atop a rocket, but return to earth to make a conventional runway landing, the latter greatly speeding up the transfer of returned cargo (e.g. science experiments material, etc.) from the vehicle to its intended destination.

Continue reading “Space Sunday: Martian “coral”, Planet Nine and Dream Chasers” →