Space Sunday: Flying on Mars, working on the Moon and visiting Europa

The Mars helicopter demonstrator: set to fly with the Mars 2020 rover mission. Credit: NASA

In November 2015 I wrote about an idea to fly a robotic drone helicopter on Mars as a part of the next rover mission, currently referred to as the Mars 2020 mission. On May 11th, 2018, NASA confirmed that Mars 2020 will now include the drone, to be carried by the rover as a technology demonstrator.

The unit, under development since 2013, is quite small; the body is the size of a box of tissues, and the contra-rotating rotor blades have a diameter of a metre (39 inches). Weighing some 1.8 kg (4.4 lbs), the drone will be battery-powered, using solar cells to recharge the batteries, which will also power a dedicated heating source to help it survive the cold Martian nights.

The drone will be carried underneath the rover, which will used the same “skycrane” landing mechanism as the Mars Science Laboratory (MSL) rover Curiosity. Once a suitable location for its deployment is found, the rover will lower it to the ground and move away to let the drone commence its first flight.

An artist’s impression of the key elements in the Mars Helicopter. Credit: NASA

Up to five flights are planned over a 30-day test campaign. The first will be very short-duration, enough to allow the helicopter to ascend to around 3 metres (9 feet) and hover for 30 seconds while the flight systems are checked out. Later flights will last up to 90 seconds and travel as far as a few hundred metres before landing to allow the solar panels to recharge the battery system.

Flying any sort of aircraft on Mars is a significant challenge. For example, the atmosphere of Mars is only one percent that of Earth, or the equivalent of being 30 km (100,000 feet) above the surface of the Earth – more the double the altitude any helicopter has been able to fly. This means the drone has to be both very lightweight and extremely powerful for its size if it is to get airborne on Mars.

To make it fly at that low atmospheric density, we had to scrutinize everything, make it as light as possible while being as strong and as powerful as it can possibly be.

– Mimi Aung, Mars Helicopter project manager

To achieve lift, The helicopter’s blades will rotate at up to 3,000 revolutions per minute, 10 times the rate of a terrestrial helicopter. The vehicle is also entirely autonomous – the time delay in Earth-Mars-Earth communications means that conventional drone flight under human control is impossible.

Mimi Aung, Mars Helicopter project manager. Credit: NASA

Instead, flight parameters will be uploaded to the Mars 2020 rover for relay to the helicopter, which will also be able to receive and act on additional instructions sent by the rover so that it doesn’t have to carry the entire flight plan within its own computer.

NASA sees Mars Helicopter as demonstrating how aerial vehicles might serve as scouts for future missions to Mars. This idea is explored in the most recent video promoting the mission, with a helicopter scanning and image the terrain around a rover.

The ability to see clearly what lies beyond the next hill is crucial for future explorers. With the added dimension of a bird’s-eye view from a ‘marscopter,’ we can only imagine what future missions will achieve.

– Thomas Zurbuchen, NASA associate administrator for science

As a technology demonstrator,the Mars Helicopter is seen as a high-rick project, although NASA has been keen to stress that if the helicopter fails for any reason, it will not impact the overall Mars 2020 mission. Nevertheless, the news the project will be carried on the rover mission hasn’t been positively received in all quarters – including within the Mars 2020 mission itself.

I am not an advocate for the helicopter, and I don’t believe the Mars 2020 project has been an advocate for the helicopter.

– Ken Farley, project scientist for Mars 2020

The concern among the rover science team is that the helicopter’s planned 90-day test campaign will prove to be a disruption in the rover’s overall science mission. However, Farley also indicated that the rover team are working to integrate the helicopter into the rover’s mission and accommodate its requirements.

Continue reading “Space Sunday: Flying on Mars, working on the Moon and visiting Europa”

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Space Sunday: insight on InSight

via Associated Press

On Saturday, May 5th, 2018, NASA commenced the latest in its ongoing robot exploration missions to Mars, with the launch of the InSight lander mission.

The Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight) mission is the first designed to carry out a detailed examination of the Red Planet’s interior – its crust, mantle and core.

Studying Mars’ interior structure can answer key questions about the early formation of the rocky planets in our inner solar system – Mercury, Venus, Earth, and Mars – more than 4 billion years ago. In addition, the data gathered may also help us to understand how rocky exoplanets orbiting other stars in our galaxy may have formed.

As well as potentially being a ground-breaking mission, InSight’s departure from Earth marked the first time any US interplanetary mission had been launched from the West Coast, rather than the more familiar Kennedy Space Centre in Florida. InSight started its six-month journey to Mars atop a United Launch Alliance Atlas V 401 launch vehicle from Space Launch Complex 3-East at Vandenberg Air Force Base, California, lifting-off at 04:05 PDT (07:05 EDT; 11:05 UTC) on May 5th, marking the end of a 2-year delay for the mission.

That delay had been caused by the repeated failure of a vacuum sphere forming a part of a set of seismometers called the Seismic Experiment for Interior Structure (SEIS) package, a crucial part of the mission’s science. Attempts to correct the issue with the French-developed package consistently led to further problems until, in December 2015, NASA was forced to call off InSight’s planned March 2016 launch while the unit was France for further repairs – a move that gave rise to fears the entire mission would be cancelled if a solution could not be found in time for InSight to meet the next launch opportunity in 2018 – such launch windows occurring every 26 months.

The mission critical vacuum sphere originally designed by CNES, and which kept failing tests and caused a 2-year delay in InSight’s launch. Credit: CNES

The mission was saved in March 2016 – a week after its original launch date in fact – when NASA’s Jet Propulsion Laboratory (JPL) reached an agreement with the French space agency CNES. This allowed JPL to design, build and test a new vacuum enclosure, with CNES taking responsibility for integrating it with the SEIS package, and testing the completed unit in readiness for integration with the lander in time for a May 2018 launch.

On May 5th 2018, the launch itself proceeded smoothly, with the Atlas V booster quickly obscured by pre-dawn fog shortly after clearing the launch complex. however, it was caught at altitude by a NAA observation aircraft, as it rose above the cloud tops. As well as InSight, the rocket carried within its payload fairings two “cubesats”, each roughly the size of a briefcase, called MarCO A and MarCO B.

Together, these tiny, self-contained satellites for the Mars Cube One (MarCO) technology demonstrator. Sent on their way to Mars alongside InSight, they both operate independently of the lander, carrying their own communications and navigation experiments. Their mission is designed to provide NASA with a temporary communications relay system during InSight’s  entry, descent and landing (EDL) mission phase, as it heads towards a (hopefully) soft-landing on Mars.

Currently, surface missions to Mars are generally monitored by the Mars Reconnaissance Orbiter, which monitors transmissions from a vehicle descending towards a landing on Mars. However, it cannot simultaneously transmit that information to Earth. This means that it can be as much as an hour before the data gathered during the critical EDL phase of a surface mission can be received on Earth. MarCO will be able to simultaneously receive and transmit EDL data sent by InSight to Earth, allowing mission engineers and scientists to have a more complete picture of this critical phase of the mission that much sooner. If successful, MarCO cover pave the way to a greater use of cubesats in the exploration of Mars.

An artist’s impression of MarCO A and MarCO B with their communications antennae deployed post-launch and on their way to Mars. Credit: NASA/JPL

Continue reading “Space Sunday: insight on InSight”

Space Sunday: drills, flares and monster ‘planes

NASA’s Mars Science Laboratory (MSL) rover Curiosity has taken a further step along the way to retrieving and analysing samples gathered by its drill mechanism, which hasn’t been actively used since December 2016, after problems were encountered with the drill feed mechanism.

Essentially, the drill system is mounted on Curiosity’s robot arm and uses two “contact posts”, one either side of the drill bit, to steady it against the target rock. A motor – the drill feed mechanism – is then used to advance the drill head between the contact posts, bringing the drill bit into contact with the rock to be drilled, and then provide the force required to drive the drill bit into the rock. However, issues were noted with this feed mechanism, during drilling operations in late 2016, leading to fears that it could fail at some point, leaving Curiosity without the means to extend the drill head, and thus unable to gather samples.

To overcome this, MSL engineers have been looking at ways in which the feed mechanism need not be used – such as by keeping the drill head in an extended position. This is actually harder than it sounds, because the drill mechanism – and the rover as a whole – isn’t designed to work that way. Without the contact posts, there was no guarantee the drill bit would remain in steady, straight contact with a target rock, raising fears it could become stuck or even break. Further, without the forward force of the drill feed mechanism, there was no way to provide any measured force to gently push the drill bit into a rock – the rover’s arm simply isn’t designed for such delicate work.

Curiosity’s drill mechanism, showing the two contact posts (arrowed) used the steady the rover’s robot arm against a target rock, and the circular drill head and bit between them – which until December 2016, had been driven forward between the two contact posts by the drill feed mechanism, which also provided the force necessary to drive the drill bit into a rock target. Credit: NASA/JPL / MSSS

So, for the larger part of 2017, engineers worked on Curiosity’s Earth-based twin, re-writing the drill software, carrying out tests and working their way to a point where the drill could be operated by the test rover on a “freehand” basis. At the same time, code was written and tested to allow force sensors within the rover’s robot arm – designed to detect heavy jolts, rather than provide delicate feedback data – to ensure gentle and uniform pressure could be applied during a drilling operation and also monitor vibration and other feedback which might indicate the drill bit might be in difficulty, and thus stop drilling operations before damage occurs.

At the end of February 2018, the new technique was put to the test on Mars. Curiosity is currently exploring a part of “Mount Sharp” dubbed “Vera Rubin Ridge”, and within the area being studied, the science team identified a relatively flat area of rock they dubbed “Lake Orcadie”, and which was deemed a suitable location for an initial “freehand” drilling test. The rover’s arm was extended over the rock and rotated to gently bring the extended drill head in contact with the target, before a hole roughly one centimetre deep was cut into the rock. This was not enough to gather any samples, but it was sufficient to gauge how well robot arm and drill functioned.

“We’re now drilling on Mars more like the way you do at home,” said Steven Lee, a Curiosity deputy project manager on seeing the results of the test. “Humans are pretty good at re-centring the drill, almost without thinking about it. Programming Curiosity to do this by itself was challenging — especially when it wasn’t designed to do that.”

The test drill site of “Lake Orcadie”, “Vera Rubin Ridge”, imaged by Curiosity’s Mastcam on February 28th, 2018, following the initial “freehand” drilling test. Credit: MASA/JPL / MSSS

The test is only the first step to restoring Curiosity’s ability to gather pristine samples of Martian rocks, however. The next test will be to drive the drill bit much deeper – possibly deep enough (around 5 cm / 2 inches) to gather a sample. If this is successful, then the step after that will be to test a new technique for delivering a gathered sample to its on-board science suite.

Prior to the drill feed mechanism issue, samples were initially graded and sorted within the drill mechanism using a series of sieves called CHIMRA – Collection and Handling for In-Situ Martian Rock Analysis, prior to the graded material between deposited in the rover’s science suite using its sample scoop. This “sieving” of a sample was done by upending the drill and then rapidly “shaking” it using the feed mechanism, forcing the sample into CHIMRA. However, as engineers can no longer rely on the drill feed mechanism, another method to transfer samples to the rover’s science suite has had to be developed.

This involves placing the drill bit directly over the science suite sample ports, then gently tapping it against the sides of the ports to encourage the gathered sample to slide back down the drill bit and into the ports. This tapping has been successfully tested on Earth – but as the Curiosity team note, Earth’s atmosphere and gravity are very different from that of Mars. So whether rock powder will behave there as it has here on Earth remains a further critical test for Curiosity’s sample-gathering abilities.

More Evidence Proxima b Unlikely To Be Habitable

Since the confirmation of its discovery in August 2016, there has been much speculation on the nature of conditions which may exist on Proxima b, the Earth-sized world orbiting our nearest stellar neighbour, Proxima Centauri, 4.25 light years away from the Sun.

Although the planet – roughly 1.3 times the mass of Earth – orbits its parent star at a distance of roughly 7.5 million km (4.7 million miles), placing it within the so-called “goldilocks zone” in which conditions might be “just right” for life to gain a foothold on a world, evidence has been mounting that Proxima b is unlikely to support life.

Comparing Proxima b with Earth. Credit: Space.com

The major cause for this conclusion is that Proxima Centauri is a M-type red dwarf star, roughly one-seventh the diameter of our Sun, or just 1.5 times bigger than Jupiter. Such stars are volatile in nature and prone stellar flares. Given the proximity of Proxima-B its parent, it is entirely possible such flares could at least heavily irradiate the planet’s surface, if not rip away its atmosphere completely.

This was the conclusion drawn in 2017 study by a team from NASA’s Goodard Space Centre (see here for more). Now another study adds further weight to the idea that Proxima b is most likely a barren world.

In Detection of a Millimeter Flare from Proxima Centauri, a team of astronomers using the ALMA Observatory report that a review of data gathered by ALMA whilst observing Proxima Centauri between January 21st to April 25th, 2017, reveals the star experienced a massive flare event. At its peak, the event of March 24th, 2017, was 1000 times brighter than the “normal” levels of emissions for the star, for a period of ten seconds. To put that in perspective, that’s a flare ten times larger than our Sun’s brightest flares at similar wavelengths.

An artist’s impression of Proxima b with Proxima Centauri low on the horizon. The double star above and to the right of it is Alpha Centauri A and B. The ALMA study suggests that it is very unlikely that Proxima b retains any kind of atmosphere, as suggested by this image. Credit: ESO

While the ALMA team acknowledge such ferocious outbursts from Proxima Centauri might be rare, they also point out that such outbursts could still occur with a frequency that, when combined with smaller flare events by the star, could be sufficient enough to have stripped the planet’s atmosphere away over the aeons.

“It’s likely that Proxima b was blasted by high energy radiation during this flare,” Meredith A. MacGregor, a co-author of the study stated as the report was published. “Over the billions of years since Proxima b formed, flares like this one could have evaporated any atmosphere or ocean and sterilised the surface, suggesting that habitability may involve more than just being the right distance from the host star to have liquid water.”

Which is a bit of a downer for those hoping some form of extra-solar life, however basic, might be sitting in what is effectively our stellar back yard – but exoplanets are still continuing to surprise us, both with their frequency and the many ways in which they suggest evolutionary paths very different to that taken by the solar system.

Continue reading “Space Sunday: drills, flares and monster ‘planes”

Space Sunday: Mars rover round-up

Curiosity, NASA’s Mars Science Laboratory (MSL) continues its exploration and examination of “Vera Rubin Ridge” on the slopes of “Mount Sharp”.

Most recently, star- and swallowtail-shaped tiny, dark bumps in fine-layered bright bedrock have been drawing the attention of the rover’s science team due to their similarity to gypsum crystals formed in drying lakes on Earth – although multiple possibilities for the features are being considered alongside their potential for being formed as a result of water action.

The features pose a number of puzzles: where they formed at the same time as the layers of sediment in which they sit, or were formed later as a result of some action? Might they have been formed inside the rock sediments of “Mount Sharp” and exposed over time as a result of wind erosion? Do they contain the mineral that originally crystallised in them, or was it dissolved away to be replaced by another? Answering these questions may point to evidence of a drying lake within Gale Crater, or to groundwater that flowed through the sediment after it became cemented into rock.

“Vera Rubin Ridge” stands out as an erosion-resistant band on the north slope of lower Mount Sharp inside Gale Crater. It was a planned destination for Curiosity even before the rover’s 2012 landing on the crater floor near the mountain. The rover began climbing the ridge about five months ago, and has now reached the uphill, southern edge. Some features here might be related to a transition to the next destination area uphill, which is called the “Clay Unit” because of clay minerals detected from orbit.

In addition to the deposits, the rover team also is investigating other clues on the same area to learn more about the Red Planet’s history. These include stick-shaped features the size of rice grains, mineral veins with both bright and dark zones, colour variations in the bedrock, smoothly horizontal laminations that vary more than tenfold in thickness of individual layers, and more than fourfold variation in the iron content of local rock targets examined by the rover.

A mineral vein with bright and dark portions distinguishes this Martian rock target, called “Rona,” near the upper edge of “Vera Rubin Ridge” on Mount Sharp. The MAHLI camera on NASA’s Curiosity Mars rover took the image after the rover brushed dust off the grey area, roughly 5cm by 7.5 inches. Click for full size. Credit: NASA/JPL / MSSS

The deposits are about the size of a sesame seed. Some are single elongated crystals. Commonly, two or more coalesce into V-shaped “swallowtails” or more complex “lark’s foot” or star configurations. They are characteristic of gypsum crystals, a form of calcium sulphate which can form when salts become concentrated in water, such as in an evaporating lake.

“These tiny ‘V’ shapes really caught our attention, but they were not at all the reason we went to that rock,” said Curiosity science team member Abigail Fraeman of NASA’s Jet Propulsion Laboratory. “We were looking at the colour change from one area to another. We were lucky to see the crystals. They’re so tiny, you don’t see them until you’re right on them.”

“There’s just a treasure trove of interesting targets concentrated in this one area,” Curiosity Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory, adds. “Each is a clue, and the more clues, the better. It’s going to be fun figuring out what it all means.”

In January, Curiosity examined a finely laminated bedrock area dubbed “Jura”, thought to result from lake bed sedimentation, as has been true in several lower, older geological layers Curiosity has examined. This tends to suggest the crystals formed as a lake in the crater evaporated. However, an alternate theory is that they formed much later, as a result of salty fluids moving through the rock during periodic “wet” bouts in the planet’s early history. This would again be consistent with features previous witnessed by Curiosity in its past examination of geological layers, where subsurface fluids deposited features such as mineral veins.

The surface of the Martian rock target in this stereo, close-up image from the Curiosity rover’s MAHLI camera includes small hollows with a “swallowtail” shape characteristic of gypsum crystals. The view appears three-dimensional when seen through blue-red glasses with the red lens on the left. Click for full size. Credit: NASA/JPL / MSSS

That the deposits may have formed as a result of fluids moving down the slopes of “Mount Sharp” is pointed to by some of them being two-toned – the darker portions containing more iron, and the brighter portions more calcium sulphate. These suggest the minerals which originally formed the features have been replaced or removed by water. The presence of calcium sulphate suggests salts were suspended in any water which may have once been present in the crater. If this is the case, it could reveal more about the past history of Mars.

“So far on this mission, most of the evidence we’ve seen about ancient lakes in Gale Crater has been for relatively fresh, non-salty water,” Vasavada said. “If we start seeing lakes becoming saltier with time, that would help us understand how the environment changed in Gale Crater, and it’s consistent with an overall pattern that water on Mars became more scarce over time.”

Even if the deposits formed inside the sediments of “Mount Sharp” and were exposed over time as a result of wind erosion, it would reveal a lot about the region, providing evidence that as water became more and more scarce, so it moved underground, taking any minerals which may have been suspended within it along as well.

“In either scenario – surface or underground formation –  these crystals are a new type of evidence that builds the story of persistent water and a long-lived habitable environment on Mars,” Vasavada notes.

As well as offering further evidence of Gale Crater having once being the home of multiple wet environments, the presence of iron content in the veins and features might provide clues about whether the wet conditions in the area were favourable for microbial life. Iron oxides vary in their solubility in water, with more-oxidized types generally less likely to be dissolved and transported. An environment with a range of oxidation states can provide a battery-like energy gradient exploitable by some types of microbes.

Opportunity’s Mystery

As Curiosity explores “Vera Rubin Ridge”, half a world away, NASA’s Mars Exploration Rover (MER) Opportunity has reached 5,000 Sols (Martian days) of operations on Mars in what was originally seen as a 90-day surface mission.

A view from the front Hazard Avoidance Camera on NASA’s Mars Exploration Rover Opportunity shows a pattern of rock stripes on the ground, a surprise to scientists on the rover team. It was taken in January 2018, as the rover neared Sol 5000 of what was planned as a 90-Sol mission. Credit: NASA/JPL

Currently, Opportunity is investigating a mystery of its own: a strange  ground texture resembling stone striping seen on some mountain slopes on Earth that result from repeated cycles of freezing and thawing of wet soil. The texture has been found within a channel dubbed “Perseverance Valley” the rover is exploring in an attempt to reach the floor of Endeavour crater. This 22 km (14 mi) diameter impact crater has been the focus of Opportunity’s studies since it reached the edge of the crater in October 2011.

The striping takes the form of soil and gravel particles appearing to be organised into narrow rows or corrugations, parallel to the slope, alternating between rows with more gravel and rows with less. One possible explanation for their formation is that on a scale of hundreds of thousands of years, Mars goes through cycles when the tilt, or obliquity, of its axis increases so much that some of the water now frozen at the poles vaporises into the atmosphere and then becomes snow or frost accumulating nearer the equator and around the rims of craters like Endeavour.

Continue reading “Space Sunday: Mars rover round-up”

Space Sunday: of life elsewhere and launches

Titan’s structure (via wikipedia)

Saturn’s giant moon, Titan, has been a source of speculation of decades. Shrouded in a dense, methane-nitrogen rich atmosphere, potentially harbouring a liquid water ocean beneath its crust, the moon has long be thought to have the conditions in which basic life might arise.

The joint NASA-ESA Cassini-Huygens mission has, over the span of thirteen years, added immeasurably to our understanding of Titan – and to the mysteries of its potential. In doing so, it has also provided us with evidence of processes taking place which are the precursors to the development of life. For example, we know that within Titan’s ionosphere, nitrogen, carbon and hydrogen are exposed to sunlight and energetic particles from Saturn’s magnetosphere. This exposure drives a process wherein these elements are transformed into more complex prebiotic compounds, which then drift down towards the lower atmosphere and form a thick haze of organic aerosols that are thought to eventually reach the surface.

However, while the drivers of the process are known, the nature of the process itself has been something of a mystery – one which an international team of scientists led by the University College London (UCL) think they now understand.  In Carbon Chain Anions and the Growth of Complex Organic Molecules in Titan’s Ionosphere the team identify Titan’s upper atmosphere contains a negatively charged species of linear molecule in Titan’s atmosphere called “carbon chain anions” – which, it has in the past been theorised, may have acted as the basis for the earliest forms of life on Earth.

The molecules were detected by CAPS, the Cassini Plasma Spectrometer, as the vehicle passed through the upper reaches of Titan’s atmosphere on a final flyby before commencing its “Grand Finale” of flights between Saturn and its rings. The discovery came as a surprise, as carbon chain anions are highly reactive, and should not survive long in Titan’s atmosphere. However, what particularly caught the attention of the science team was that the data show that the carbon chains become depleted closer to the moon, while precursors to larger aerosol molecules undergo rapid growth. This suggests a close relationship between the two, with the carbon chains ‘seeding’ the larger molecules – those prebiotics mentioned above – which then fall to the surface.

How complex molecules are thought to form in Titan’s atmosphere. Credit: UCL

“We have made the first unambiguous identification of carbon chain anions in a planet-like atmosphere, which we believe are a vital stepping-stone in the production line of growing bigger, and more complex organic molecules, such as the moon’s large haze particles,” said Ravi Desai, the lead author for the study in a press release from UCL.

He continued, “This is a known process in the interstellar medium – the large molecular clouds from which stars themselves form – but now we’ve seen it in a completely different environment, meaning it could represent a universal process for producing complex organic molecules. The question is, could it also be happening at other nitrogen-methane atmospheres like at Pluto or Triton, or at exoplanets with similar properties?”

With its rich mix of complex chemistry coupled with its basic composition, Titan is something of a planetary laboratory; one which probably mirrors the very early atmosphere surrounding Earth before the emergence of oxygen-producing micro-organisms which started the transformation of our atmosphere into something far more amenable for the advance of life. As such, the discovery of carbon chain anions in Titan’s atmosphere potentially confirms that long-held theory that they help kick-start the life creating processes here on Earth, and suggest conditions on Titan might allow the same to happen there. It also offers insight into how life might start elsewhere in the galaxy.

“These inspiring results from Cassini show the importance of tracing the journey from small to large chemical species in order to understand how complex organic molecules are produced in an early Earth-like atmosphere,” Dr Nicolas Altobelli, ESA’s Cassini project scientist, said in the same press release. “While we haven’t detected life itself, finding complex organics not just at Titan, but also in comets and throughout the interstellar medium, we are certainly coming close to finding its precursors.”

Dream Chaser ISS Flights target 2020 Commencement

Sierra Nevada Corporation (SNC) has confirmed than United Launch Alliance (ULA) will provide the veritable Atlas V booster as the launch vehicle for the Dream Chaser Cargo mini-shuttle, which will be joining fleet of uncrewed vehicles from America, Russia and Japan keeping the International Space Station (ISS) supplied with consumables, equipment and science experiments. The company also indicate that launches of the vehicle could start in 2020.

The Altas V – Cream Chaser Cargo launch configuration. Credit: United Launch Alliance

Dream Chaser was originally conceived to fly crews to and from the ISS as part of NASA’s commercial crew transportation joint venture with the private sector. Four companies vied for contracts to supply NASA with vehicles capable of shuttling up to six personnel to and from the space station. Despite being one of the most advanced of the designs in terms of feasibility and development, the Dream Chaser was not selected for that work, with NASA opting for the SpaceX Dragon 2 vehicle and Boeing’s CST-100 Starliner capsule.

However, support within the US space agency for the Dream Chaser continued, allowing SNC to propose the development of Dream Chaser Cargo, a revised version of the original concept, capable of supplying up to 5.5 tonnes of cargo to the ISS. In January 2016, in renewing its contract with SpaceX (Dragon) and Orbital ATK (Cygnus) for such resupply missions, NASA extended it to include SNC. This was followed a year ago by formal approval being given for Dream Chaser missions to the ISS, which allowed SNC to push ahead with testing of the revised vehicle.

Dream Chaser will launch atop the commercial Atlas V in its most powerful configuration, dubbed Atlas V 552, with five strap on solid rocket motors and a dual engine Centaur upper stage. The cargo vehicle will be held inside a five metre diameter payload fairing with its wings folded. Cargo will be carried both within the vehicle itself and in a support module mounted on the rear of the spacecraft, which will also house a docking adaptor for connecting with the space station. The latter will be supplied to SNC by the European Space Agency, which is also supplying NASA with the Service Module for the Orion multi-Purpose Crew Vehicle.

The Dream Chaser Cargo, built by SNC, and the International Berth and Docking Mechanism, to be supplied to SNC for Dream Chaser flights by the European Space Agency. Credit: SNC

In addition to flying up to 5.5 tonnes to the ISS, Dream Chaser Cargo will be able to return some 2 tonnes of equipment, experiments and other items from the space station to Earth, where it will make a conventional runway landing using the former space shuttle runway at Kennedy Space Centre – or any other suitable landing facility in the United States.

It is expected that Dream Chaser cargo will fly a total of six missions to the ISS between 2020 and 2024, when it is currently anticipated the space station will be decommissioned.

Continue reading “Space Sunday: of life elsewhere and launches”

Space Sunday: Flying over Mars, JUICE for Jupiter and black holes

An impact crater which formed between July 2010 and May 2012 and imaged by the HiRISE camera on the Mars Reconnaissance Orbiter, is one of the locations featured in “A Fictive Flight Above Real Mars” by Jan Fröjdman. Credit: Jan Fröjdman; original anaglyph image NASA/JPL / University of Arizona

Ever wondered what it would be like to actually fly over Mars? I have – although I admit, I’m utterly entranced by that red world and the potentials it presents. Finnish film-maker Jan Fröjdman has as well – only he’s taken the idea a step further and produced a remarkable video,  A Fictive Flight Above Real Mars. Last just over 4.5 minutes, the film takes us on a flight over some of the must remarkable scenery imaginable, using high-resolution images and data returned by NASA’s Mars Reconnaissance Orbiter (MRO).

It’s a stunning piece showing many of the more intriguing features of Mars: the recent impact crater see in the still at the top of this article; the ice walls and melt holes of the Martian poles; gullies and cliffs rutted and marked by RSLs – recurring slope lineae – which might or might not be the result of liquid activity; the ripples of sand dunes, and the winding forms of channels which might have been shaped by the passage of water.

To make the film, Fröjdman used 3-D anaglyph images from HiRISE (the High Resolution Science Imaging Experiment aboard MRO), which contain information about the topography of Mars surface. The work involved manually picking more than 33,000 reference points in the anaglyph images, and then processing the results through six pieces of software to achieve a sense of motion and panning across the surface of Mars.

In putting the film together, Fröjdman  wanted to create a real feeling of flying over Mars and of recapturing the feel of video footage shot by the Apollo astronauts as they orbited the Moon. To help with the latter, he overlaid the video with image cross-hairs of the kind seen in some of the Apollo footage, and added little bursts of thruster firings to simulate a vehicle manoeuvring in the thin atmosphere. The film concludes with a main engine firing, presumably to lift the vehicle back into orbit.

NASA and SpaceX Consider Red Dragon Landing Site

And staying with Mars: NASA and SpaceX have started the process of selecting a landing site for SpaceX’s planned Red Dragon mission to Mars in 2020. The ambitious mission will see the company attempt to land a 10-tonne Red Dragon capsule on Mars purely by propulsive means. While paid for entirely by the company, the mission will feature a science suite provided by NASA.

There are two major criteria governing any landing site location: scientific interest, and the potential for colonisation – the 2020 mission being the first of a number which SpaceX plans to uses as precursors for human missions to Mars. As such, it had initially been decided that any landing sites put forward must be near the equator, for solar power; near large quantities of ice, for water and at low elevation, for better thermal conditions.

NASA initially identified four potential locations on Mars’ northern hemisphere which meet the broad criteria for the mission – but examination of three of them using the HiRISE system on the Mars Reconnaissance Orbiter showed they are rocky enough to pose a threat to landing a vehicle the size and mass of Red Dragon. This currently leaves a short-list of one, in the shape of Arcadia Planitia, a smooth plain containing fresh lava flows and which has a large region that was shaped by periglacial processes which suggest that ice is present just beneath the surface.

Acadia Planitia is the current sole contender to be the landing site for the SpaceX Mars 2020 mission

However, negating this is the plain’s relatively high northern latitude (40-60 degrees north), which would reduce the amount of sunlight a base of operations there would receive in the winter months. While Amazonis Planitia to the south offers a similar youthful surface, much of which is relatively smooth, it is largely volcanic in origin and unlikely to harbour sub-surface water ice which can be easily accessed.

Given both of these point, it is likely other possible landing sites will be proposed in the coming months.

Curiosity Reveals More Wheel Damage

It’s been a while since my last report on NASA’s Mars Science Laboratory rover, Curiosity. This is mostly being the updates coming out of JPL have slowed mightily in recent months.

At present, Curiosity is examining sand dunes on the lower slopes of “Mount Sharp”. Once finished, it will proceed up higher to a feature known as “Vera Rubin Ridge”, inspecting a layer that is rich in the mineral hematite. From there, it will proceeded to even higher elevations to inspect layers that contain clays and sulphates. This will require a drive of some 6 km (3.7 mi) uphill, and so will require time to complete.

A recurring area of concern for the mission – albeit not serious at this point – is the wear and tear on the rover’s wheels. In 2013, Curiosity suffered greater than expected damage to its six wheels while traversing some exceptionally rough terrain.  Although the damage was nowhere near severe enough to impeded the rover’s driving abilities, it did result in engineers keeping a much closer eye on the condition of Curiosity’s wheels using the imaging system mounted on the rover’s robot arm.

The latest of these checks was performed on  Sunday, March 19th, 2017, and it revealed two small breaks in the raised treads (“grousers”) on the rover’s left middle wheel. These seem to have occurred since the last wheel check at the end of January, 2017. These treads perform two major tasks: bearing the brunt of the rover’s weight and providing most of the traction for a wheel.

The broken “grousers” (“treads”) on one of Curiosity’s six wheels, together with older puncture holes through the wheel, as imaged on March 19th, 2017. Credit: NASA/JPL

Following the 2013 damage, testing on Earth suggested that significant breaks in three “grousers” on a wheel would indicate it has passed 60% of its expected lifespan. However, the mission team emphasise the rover has already driven more than 60% of the total distance needed for it to make it to all of its scientific destinations. As such, while the breaks will be monitored, they are not a cause for immediate or grave concern.

Overall, confidence remains high that Curiosity will achieve all of its expected science goals and will likely make an extended traverse up the side of “Mount Sharp”.

A rover’s progress: the 16 km (10 mi) travelled by Curiosity so far, and potential for future explorations up the side of Aeolis Mons. Credit: NASA/JPL / T. Reyes

Continue reading “Space Sunday: Flying over Mars, JUICE for Jupiter and black holes”