NASA’s Orion space capsule that is set to get humans to Mars is about to make its maiden flight.
Orion will be launched on a Delta rocket out of Cape Canaveral in Florida on a short journey above the Earth to test key technologies.
The conical vessel is reminiscent of the Apollo command ships that took men to the Moon in the 1960s and 1970s, but bigger and with cutting-edge systems.
Given that this is a first outing, there will be no people aboard.
Nonetheless, the NASA describes the demonstration as a major event.
NASA has a window in which to launch Orion of about two-and-a-half hours, which began at 07:05 local time.
The launch preparations had to be stopped shortly before the opening of the window because a boat strayed into the eastern part of the launch range. After that, the countdown had to be held because of strong winds and a technical issue.
Orion is being developed alongside a powerful new rocket that will have its own debut in 2017 or 2018.
Together, they will form the core capabilities needed to send humans beyond the International Space Station to destinations such as the Red Planet.
For Thursday’s flight, the Delta IV-Heavy rocket – currently the beefiest launcher in the world – is being used as a stand-in.
It will send Orion twice around the globe, throwing the ship up to an altitude of almost 3,600 miles.
This will set up a fast fall back to Earth, with a re-entry speed into the atmosphere close to 20,000mph – near what would be expected of a capsule coming back from the Moon.
It should give engineers the opportunity to check the performance of Orion’s critical heat shield, which is likely to experience temperatures in excess of 4,000F.
They will also watch how the parachutes deploy as they gently lower the capsule into Pacific waters off Mexico’s Baja California Peninsula.
Black Beauty, a rock discovered in the Sahara Desert, has been identified as the oldest Martian meteorite ever found, scientists say.
Earlier research had suggested Black Beauty was about 2 billion-year old, but new tests indicate the rock actually dates to 4.4 billion years ago.
The dark and glossy meteorite would have formed when the Red Planet was in its infancy.
The research is published in the journal Nature.
Lead author Prof. Munir Humayan, from Florida State University, US, said: “This [rock] tells us about one of the most important epochs in the history of Mars.”
There are about 100 Martian meteorites, but almost all of them are younger, dating to between 150 million and 600 million years old.
They would have fallen to the Earth after asteroid or comet impacts had dislodged them, setting the rocks free to travel through space before eventually crash landing here.
This particular Martian meteorite, which is formed of five fragments, is much older.
Black Beauty rock has been identified as the oldest Martian meteorite ever found
An earlier analysis of one piece, called NWA 7034, put the age at 2 billion years.
But this latest research has found that another piece, NWA 7533, dates to 4.4 billion years ago, which suggests that NWA 7034 also must be older.
The team said it would have formed when Mars was just 100 million years old.
“It is almost certainly coming from the southern highlands – the cratered terrain that makes up the southern hemisphere of Mars,” said Prof. Munir Humayan.
This would have been a turbulent period of Martian history, when volcanoes were erupting all over the surface.
Prof. Munir Humayan explained: “The crust of Mars must have differentiated really quickly, rather than gradually over time. There was a big volcanic episode all over the surface, which then crusted up, and after that the volcanism dropped dramatically.
“When it did this it also must have out-gassed water, carbon dioxide, nitrogen and other gases to produce a primordial atmosphere… and also a primordial ocean.”
He added: “This is a very exciting period of time – if there were to be life on Mars, it would have originated at this particular time.”
Prof. Munir Humayan said that team now plans to study the rock to see if there were any signs of past life. But he added that while the rock was lying in the Sahara Desert, living organisms probably would have occupied it, masking potential evidence.
The orbiter was launched on an Atlas V rocket from Florida’s Cape Canaveral Air Force Station at 13:28 local time.
Assuming the $671million mission stays on track, the probe will have a 10-month cruise to the Red Planet.
MAVEN is going to study Mars’ high atmosphere, to try to understand the processes that have robbed the world of most of its air.
Evidence suggests the planet was once shrouded in a thick blanket of gases that supported the presence of liquid water at its surface. Today, the air pressure is so low that free water would instantly boil away.
MAVEN was released from the Atlas V’s upper-stage some 53 minutes after leaving the Cape Canaveral pad. The probe then had to open its solar panels and orientate itself into a cruise configuration.
“During cruise, we perform four planned trajectory correction manoeuvres where we fire thrusters to tweak the trajectory so that we arrive at the right place and time to go into orbit around Mars. At that point, we will fire a set of thrusters to slow down the spacecraft and get captured into orbit,” explained Guy Beutelschies, the spacecraft’s programme manager at manufacturer Lockheed Martin.
The present-day atmosphere of Mars, composed mostly of carbon dioxide, is extremely thin, with atmospheric pressure at the surface just 0.6% of the Earth’s surface pressure.
NASA’s MAVEN mission has set off for Mars
The Martian landscape, though, retains channels that were evidently cut by abundant, flowing water – proof that the planet had a much denser atmosphere in the past.
Some of the air would certainly have reacted with, and been incorporated into, minerals at the surface.
But the most likely explanation for its loss is that the solar wind – the great outflow of energetic particles from the Sun – has simply eroded it through time.
This has been possible because, unlike Earth, the Red Planet lacks a protective global magnetic field, which is capable of deflecting the abrasive assault from our star.
MAVEN (the Mars Atmosphere and Volatile EvolutioN spacecraft) is equipped with eight instruments – some to understand the Sun’s influence at Mars; others to investigate the composition and behavior of the atmosphere. The intention is to measure the rates at which different air molecules are being lost today, distinguishing between the various processes responsible.
Scientists will use this information to get some insights into the history of the Martian climate – from the time billions of years ago when it was warmer and wetter, and potentially habitable to life, to the present environment which is cold and desiccated.
“Most of the loss is thought to have occurred early in Mars’ history when the Sun and the solar wind were more intense,” said Bruce Jakosky, MAVEN’s principal investigator from the University of Colorado at Boulder.
“The loss rates today are low enough that we’re probably not going to see the loss of the entire atmosphere. The reason we are studying it today, even though the loss rates are so much lower, is that we can understand the specific processes that are going on and learn how to extrapolate them back in time.”
Arrival at Mars is timed for September 22, 2014.
“MAVEN will be in an elliptical orbit that ranges as far away as 6,220 km and as close as 150 km,” said Guy Beutelschies.
“We will also execute a set of operations to dip down into the tenuous upper reaches of the atmosphere to do some direct sampling for approximately a week at a time. These are called ‘deep dips’ and we do five of them during the primary mission.”
That primary mission lasts one Earth year (half a Mars year), after which the science team will need additional funding to continue their investigations.
NASA, though, fully intends to keep operating MAVEN long into the future as a data-relay platform for surface rovers like Curiosity.
“If things go nominally, we should have fuel left onboard to keep the vehicle flying for years beyond its design life,” according to NASA.
“As a reference, Mars Odyssey was launched in 2001 and is still operating.”
India launched its Mangalyaan mission to Mars on November 5 but is taking a less direct trajectory to the Red Planet than MAVEN, which means the US mission should get into orbit just a few days before the other orbiter.
Scientists have found definitive proof that many of the landscapes seen on Mars were indeed cut by flowing water.
The valleys, channels and deltas viewed from orbit have long been thought to be the work of water erosion, but it is NASA’s latest rover, Curiosity, that has provided the “ground truth”.
Researchers report its observations of rounded pebbles on the floor of the Red Planet’s 100 mile-wide Gale Crater.
Their smooth appearance is identical to gravels found in rivers on Earth.
Rock fragments that bounce along the bottom of a stream of water will have their edges knocked off, and when these pebbles finally come to rest they will often align in a characteristic overlapping fashion.
Curiosity has pictured these features in a number of rock outcrops at the base of Gale Crater.
It is confirmation that water has played its part in sculpting not only this huge equatorial bowl but by implication many of the other landforms seen on the planet.
“For decades, we have speculated and hypothesized that the surface of Mars was carved by water, but this is the first time where you can see the remnants of stream flow with what are absolutely tell-tale signs,” said Dr. Rebecca Williams from the Planetary Science Institute.
Mars valleys, channels and deltas viewed from orbit have long been thought to be the work of water erosion
NASA first announced the discovery of the pebbles in September last year, barely seven weeks after Curiosity had landed in Gale.
Researchers have since been studying the robot’s pictures in more detail and have now written up a report for Science magazine – the first scholarly paper from the surface mission to make it into print; and the study reinforces the initial interpretation.
It describes the nature of the outcrops, and estimates the probable conditions in which their sediments were laid down.
The pebbles range in size from about two to 40 mm in diameter – too big to have been blown along by the wind.
These clasts, as scientists will often call them, are cemented together in a sandy matrix to make a rock type referred to as a conglomerate.
In many places, the clasts are touching each other, and the pictures show examples of so-called imbrication – an arrangement where elongated pebbles stack like a row of toppled dominos. It is a classic sign of past river activity.
Precisely dating landforms on Mars is not possible, but the rock outcrops seen by the rover are almost certainly more than three billion years old.
Curiosity’s pictures have enabled the team to make some informed statements about the speed and depth of the water that once flowed across the crater floor.
The pebbles come in a variety of dark and light shades, further indicating that they have been eroded from different rock types and transported from different locations.
Using its Chemcam remote-sensing laser, the rover was able to detect feldspar in the lighter toned clasts.
Feldspar is a common mineral on Earth that weathers quickly in the presence of water.
This suggests past conditions were not overly wet and that the pebbles were carried only a relatively short distance – probably no more than 10-15km.
This fits with satellite observations of what appears to be a nearby network of old rivers or streams spreading away from the mouth of a channel that cuts through the northern rim of Gale Crater.
This valley – or Peace Vallis as it is known – is the probable route down which the water flowed and later dumped its load of rounded gravels.
Curiosity is due to drive back on itself in the coming weeks as it makes for the big peak, Mount Sharp, at the centre of the crater.
Scientists hope this will take the vehicle past similar rock outcrops so that additional pictures can be obtained.
NASA has reported that its Curiosity rover has made another significant discovery on Mars.
Curiosity has drilled into a rock that contains clay minerals – an indication of formation in, or substantial alteration by, neutral water.
Scientists say the find is one more step towards showing conditions on Mars in the distant past could have supported life.
Many rocks studied previously were probably deposited in acidic water.
While this would not have precluded the possibility of micro-organisms taking hold on Mars, it would have been more challenging, scientists believe.
Identifying clays shows there were at least some locations on the planet billions of years ago where environments would have been much more favorable.
“We have found a habitable environment that is so benign and supportive of life that probably if this water was around and you had been there, you would have been able to drink it,” said John Grotzinger, Curiosity’s project scientist.
Curiosity rover drilled a powdered sample from a mudstone at its exploration site in Gale Crater, a deep impact bowl on Mars’ equator.
This was delivered to the two big onboard laboratories, Sam and Chemin, for analysis.
The rock sample was found to contain 20-30% smectite – a particular group of clay minerals.
Their high abundance and the relative lack of salt are strongly suggestive of a fresh-water environment for the mudstone’s formation.
The presence of calcium sulphates, rather than the magnesium or iron sulphates seen in previous rock analyses at other locations on the planet, adds to the evidence that the sampled rock in Gale was deposited in a neutral to mildly alkaline pH environment.
Mars Curiosity rover has drilled into a rock that contains clay minerals, an indication of formation in, or substantial alteration by, neutral water
Scientists think Curiosity probably drilled into an ancient lakebed.
The analysis also identified sulphur, nitrogen, hydrogen, oxygen, phosphorus and carbon – some of the key chemical elements for life.
Additionally, it found compounds in a range of oxidized states, meaning there were electrons moving through the environment. Those could have been co-opted as an energy source by simple life-forms, if they ever existed in Gale.
“What we’ve learned in the last 20 years of modern microbiology is that very primitive organisms – they can derive energy just by feeding on rocks,” explained Prof. John Grotzinger.
“Just like on [a] battery – you hook up the wires and it goes to a lightbulb and the lightbulb turns on. That’s kind of what a micro-organism would have done in this environment, if life had ever evolved on Mars and it was present here.”
Curiosity rover is assembling quite a catalogue of water evidence in the crater.
Already, it has seen the remains of an ancient riverbed system, where water once flowed perhaps a metre deep and quite vigorously.
The picture that seems to be emerging is one where sediments were transported downhill from the eroding crater rim into a network of streams that then flowed into the lake environment represented by the mudstone.
Curiosity is currently working in a small depression known as Yellowknife Bay, about half a kilometre from the location where it touched down last August.
NASA’s original mission plan was to head towards the big mountain that dominates the centre of Gale Crater, but the fascinating science at Yellowknife Bay has delayed this journey somewhat.
In recent days, operations have been slowed by a software glitch, requiring the vehicle to be run off its reserve computer.
There is also the imminent issue of solar conjunction, which will see Mars move behind the Sun as viewed from Earth, blocking communications.
All this means that Curiosity will be at Yellowknife Bay for a while yet.
“Basically, we can’t talk to the rover and the rover [can’t] talk to us for most of the month of April,” said Michael Meyer, the lead scientist on NASA’s Mars exploration programme.
“We’ll do some more science activities though the end of this month, [provided] the engineers confirm it’s safe for us to do those operations. But we will not do a second drill hole until after solar conjunction.”
When the rover does finally get to the mountain, known as Mount Sharp, the expectation, based on satellite imagery, is that it will again find clay minerals.
This will enable the robot to compare and contrast past environments.
The US space agency’s Opportunity rover, which continues to work nine years on from its landing, is also believed to be sitting on top of clay-bearing rocks at its exploration site far to the west of Gale. Opportunity, however, does not have Curiosity’s capability to assess those rocks.
NASA’s Curiosity rover on Mars has finally drilled deep enough into a rock to acquire a powdered sample for analysis.
The fine grey tailings from the 6cm-hole will be sieved and inspected before being delivered to the robot’s onboard labs in the coming days.
It will represent a historic first in planetary exploration – never before has the interior of a rock on another world been probed in such a way.
The US space agency said the drilling was an immense achievement.
“This is the biggest milestone accomplishment for the Curiosity team since the sky-crane landing last August, another proud day for America,” said Prof. John Grotizinger, the mission’s chief scientist.
Drilling is absolutely central to the rover’s mission in Gale Crater, a deep bowl sited on Mars’ equator.
Curiosity is investigating whether past environments at this location could ever have supported life, and getting inside rocks to analyze their make-up will provide some of the most telling evidence.
Engineers have waited a full six months before deploying the drill tool, which is held on the end of the rover’s 2.2 m-long robotic arm.
Its first action was just to hammer down briefly on a rock target last weekend – a simple check to prove the machinery was behaving as it should.
This was followed in the week by the drill turning in the chosen rock to cut a shallow, 2cm hole.
It produced a fine powder that engineers deemed suitable to try to pick up. So, the command was given to drill a second hole that was deep enough to push some tailings into the tool’s sample acquisition chamber.
NASA’s Curiosity rover on Mars has finally drilled deep enough into a rock to acquire a powdered sample for analysis
Some of this material will be used to scrub the machinery’s innards of any contamination that may have travelled with the rover from Earth.
The rest will be sorted to a size and volume that can be put inside Curiosity’s Chemin and Sam labs.
These instruments will determine the rock sample’s precise chemistry and mineralogy, and identify any interesting carbon chemistry that may be present.
Chemin will likely set to work on the powder first. This is because its findings can influence the settings run the Sam experiments..
“We may alter our temperatures depending on what they see in Chemin,” said Paul Mahaffy, the principal investigator on Sam.
The flat slabs of rock currently being investigated by the rover have been dubbed “John Klein”, the name of a Curiosity engineer who died in 2011. They lie in a small depression referred to as Yellowknife Bay, about half a kilometre from the robot’s point of touchdown last year.
The rocks contain very fine-grained sediments but are cut through with pale veins of what could be calcium sulphate.
Curiosity has already seen plenty of evidence for past running water in Gale Crater and the results from the drill-hole analysis are expected to reveal further information about that wet history.
It was expected to be just another lump of dull basalt, but the first rock examined up close by NASA’s Curiosity rover on Mars proved to be a little more interesting.
The pyramidal object, nicknamed “Jake Matijevic” after a recently deceased mission engineer, had a composition not seen on the planet before.
Scientists have likened it to some unusual but well known rocks on Earth.
These form from relatively water-rich magmas that have cooled slowly at raised pressures, said Edward Stolper.
“[The rock is] widespread on Earth, on oceanic islands such as Hawaii, and St Helena, and the Azores; and also in rift zones like the Rio Grande and so forth. So, again, it’s not common, but it’s very well known,” the mission co-investigator from the California Institute of Technology, Pasadena, told reporters.
The Curiosity rover examined Jake Matijevic three weeks ago. At the time, the dark rock was not anticipated to have high science value; it was merely an early opportunity to use the robot’s survey instruments in unison.
Jake Matijevic rock found on Mars by Curiosity rover
Jake Matijevic also had an interesting, weathered appearance that drew attention.
The rover first zapped the rock from a distance with its ChemCam laser, and then moved in close to study it with its X-ray spectrometer known as APXS. The latter device is held on the end of the rover’s robotic arm; the laser is mounted on its mast.
Jake Matijevic was found to be high in elements consistent with the mineral feldspar, such as sodium and potassium, and low in elements such as magnesium and iron.
Prof. Edward Stolper compared the signatures with a catalogue containing thousands of Earth rocks, and determined the nearest match to be an igneous type, the formation of which he likened to the production of colonial apple jack liquor.
This saw barrels of cider left outside in winter to partially freeze. As the barrels iced up, they would concentrate the apple-flavored liquor.
A similar process was occurring in the liquid magma several kilometres underground that gave rise to alkalic rocks like Jake Matijevic, said Prof. Edward Stolper.
“In the case of the apple jack, you take out water and concentrate alcohol; in this case you take out particular minerals – olivines, pyroxenes and some feldspars – and you generate a liquid that is very different to what you started with,” he explained.
“So, the composition of Jake Matijevic is a very close match to highly crystallized or fractionated magmas that occur in particular places on Earth.”
Curiosity landed in Mars’ equatorial Gale Crater in August, and has driven eastwards almost 500 m since then.
It is currently stationed just short of a point called Glenelg, where satellite images have revealed a juxtaposition of three different types of terrain.
Scientists expect this location to be a good starting point to begin characterizing the geology of Gale.
The mission is going through something of a lull presently while the rover spends a few days preparing its sample handling system.
It is running dirt through this equipment to scrub surfaces free of any residual contamination from Earth.
This is necessary to avoid skewing the analyses of rock and soil samples delivered to the rover’s onboard laboratories later in the mission.
Curiosity’s goal is to try to determine if Gale ever supported environments that might have allowed microbial life to flourish.
In the short time it has been on the ground, it has already identified rocks that were clearly deposited in fast running water. The theory is that the rover is sitting at the head of an ancient alluvial fan where a network of streams cut across the crater floor billions of years ago.
Curiosity rover has completed its first close-contact science on Mars.
The robot pushed its arm instruments up against a pyramidal rock to assess the atomic elements that were present.
The rock – dubbed “Jake Matijevic” after a late rover engineer – was not expected to have high research value. Rather, it was regarded as an early opportunity to demonstrate the performance of the arm’s “hand lens” and X-ray spectrometer.
Curiosity has now continued driving.
Curiosity rover has completed its first close-contact science on Mars
On Monday, it moved some 42 m (138 ft), the single biggest roll for the robot since landing seven weeks ago in Mars’ equatorial Gale Crater.
The vehicle is endeavoring to get to location that scientists have nicknamed Glenelg, which satellite images have indicated is a junction between three types of geological terrain.
It is at Glenelg that Curiosity will likely use one of its key arm tools – its drill – for the first time.
Even before the rover gets to the junction, it will look for some suitable soil to scoop and deliver to its onboard laboratories for analysis.
NASA’s $2.6 billion mission touched down on the Red Planet on 6 August (GMT).
Much of the time since then has been spent commissioning the immensely complex, six-wheeled machine and its suite of 10 instruments.
The Jake Matijevic investigation allowed the science team to use the X-ray spectrometer (APXS) and the hand lens (Mahli) in unison with the rover’s infrared laser instrument (ChemCam).
The laser, which sits atop the rover’s mast, also determines the chemical composition of targets, and the rock experiment meant researchers could do some cross-calibration of APXS and ChemCam.
Little information has been released by NASA about what it saw, but then the pyramidal rock was not expected to be anything more than a standard lump of Martian basalt.
As the mission progresses, APXS and ChemCam, along with the keen eye of Mahli, will be used to survey the crater’s surface for more interesting rocks. When they identify a fascinating target, it is at that point that the drill will be commanded to acquire a sample for detailed scrutiny in the onboard laboratories.
Curiosity’s mission has been funded for one Martian year (two Earth years) of study. It will try to determine in that time whether past environments at Gale Crater could ever have supported microbial life.
NASA has released the first spectacular images taken by the Mars rover Curiosity, detailing a mound of layered rock where scientists plan to focus their search for the chemical ingredients of life on the Red Planet.
The stunning photographs reveal distinct tiers of near the base of the 3-mile-tall mountain that rises from the floor of the vast, ancient impact basin known as Gale Crater, where Curiosity landed on August 6 to begin its two-year mission.
Scientists estimate it will be a year before the six-wheeled, nuclear-powered rover, about the size of a small car, physically reaches the layers of interest at the foot of the mountain, known as Mount Sharp, 6.2 miles away from the landing site.
From earlier orbital imagery, the layers appear to contain clays and other hydrated minerals that form in the presence of water.
NASA has released the first spectacular images taken by the Mars rover Curiosity
While previous missions to Mars have uncovered strong evidence for vast amounts of water flowing over its surface in the past, Curiosity was dispatched to hunt for organic materials and other chemistry considered necessary for microbial life to evolve.
The $2.5 billion Curiosity project, NASA’s first astrobiology mission since the 1970s-era Viking probes to Mars, is the first to bring all the tools of a state-of-the-art geochemistry laboratory to the surface of a distant planet.
But the latest images from Curiosity, taken at a distance from its primary target of exploration, already have given scientists a new view of the formation’s structure.
The layers above where scientists expect to find hydrated minerals show sharp tilts, offering a strong hint of dramatic changes in Gale Crater, located in the planet’s southern hemisphere near its equator.
Mount Sharp, the name given to the towering formation at the center of the crater, is believed to be the remains of sediment that once completely filled the 96-mile-wide basin.
“This is a spectacular feature that we’re seeing very early,” project scientist John Grotzinger, with the California Institute of Technology, said as the images were released on Monday.
“We can sense that there is a big change on Mount Sharp.”
The higher layers are steeply slanted relative to the layers of underlying rock, the reverse of similar features found in Earth’s Grand Canyon.
“The layers are tilted in the Grand Canyon due to plate tectonics, so it’s typical to see older layers be more deformed and more rotated than the ones above them,” John Grotzinger said.
“In this case, you have flat-line layers on Mars overlaid by tilted layers. The science team, of course, is deliberating over what this means.”
He added: “This thing just kind of jumped out at us as being something very different from what we ever expected.”
Absent plate tectonics, the most likely explanation for the angled layers has to do with the physical manner in which they were built up, such as being deposited by wind or by water.
“On Earth, there’s a whole host of mechanisms that can generate inclined strata,” John Grotzinger said.
“Probably we’re going to have to drive up there to see what those strata are made of.”
NASA said it used the rover to broadcast a message of congratulations to the Curiosity team from NASA chief Charles Bolden, a demonstration of the high bandwidth available through a pair of U.S. science satellites orbiting Mars.
“This is the first time that we’ve had a human voice transmitted back from another planet’ beyond the moon,” said Chad Edwards, chief telecommunications engineer for NASA’s Mars missions at the Jet Propulsion Laboratory in Pasadena, California.
“We aren’t quite yet at the point where we actually have a human present on the surface of Mars … it is a small step,” Chad Edwards said.
Curiosity, the big robot rover NASA is sending to Mars, looks in excellent shape for its Monday (GMT) landing.
Curiosity – also known as the Mars Science laboratory (MSL) – was launched from Earth in November last year and is now nearing the end of a 560-million-km journey across space.
To reach its intended touch-down zone in a deep equatorial crater, the machine must enter the atmosphere at a very precise point on the sky.
Engineers told reporters on Thursday that they were close to a bulls-eye.
A slight course correction – the fourth since launch – was instigated last Saturday, and the latest analysis indicates Curiosity will be no more than a kilometre from going straight down its planned “keyhole”.
The team’s confidence is such that it may pass up the opportunity to make a further correction on Friday.
“We are about to land a small compact car on the surface with a trunk-load of instruments. This is a pretty amazing feat getting ready to happen. It’s exciting, it’s daring – but it’s fantastic,” said Doug McCuistion, the head of NASA’s Mars programme.
Curiosity, also known as the Mars Science laboratory, was launched from Earth in November last year and is now nearing the end of a 560-million-km journey across space
Curiosity is the biggest and most sophisticated Mars rover yet.
It will study the rocks inside Gale Crater, one of the deepest holes on Mars, for signs that the planet may once have supported microbial life.
The $2.5 billion mission is due to touch down at 05:31 GMT Monday 6 August; 22:31 PDT, Sunday 5 August.
It will be a totally automated landing.
Engineers here at the Jet Propulsion Laboratory (JPL) in Pasadena, California, can only watch and wait.
The vast distance between Mars and Earth means there is a 13-minute lag in communications, making real-time intervention impossible.
NASA has had to abandon the bouncing airbag approach to making soft landings.
This technique was used to great effect on the three previous rovers – Sojourner, Spirit and Opportunity.
But at nearly a ton, Curiosity is simply too heavy to be supported by inflated cushions.
Instead, the mission team has devised a rocket-powered, hovering crane to lower the rover to the surface in the final moments of its descent.
Adam Steltzner, who led this work for NASA, said: “It looks a little bit crazy. I promise you it is the least crazy of the methods you could use to land a rover the size of Curiosity on Mars, and we’ve become quite fond of it – and we’re fairly confident that Sunday night will be a good night for us.”
The team is also keeping a sharp eye on the Martian weather and any atmospheric conditions that might interfere with the descent manoeuvres.
It is the equivalent of August also on Mars right now, meaning Gale Crater at its position just inside the southern hemisphere is coming out of winter and moving towards spring.
It is the time of year when winds can kick up huge clouds of dust, and a big storm was spotted this week about 1,000km from the landing site. But NASA expects this storm to dissipate long before landing day.
The first black-and-white images of the surface taken by Curiosity should be returned to Earth in the first hours after touch down, but the mission team do not intend to rush into exploration.
For one thing, the rover has a plutonium battery that should give it far greater longevity than the solar-panelled power systems on previous vehicles.
“This is a very complicated beast,” said Pete Theisinger, Curiosity’s project manager.
“The speech I made to the team is to recognize that on Sunday night at [22:32 PDT], we will have a priceless asset that we have placed on the surface of another planet that could last a long time if we operate it correctly, and so we will be as cautious as hell about what we do with it.”
Curiosity – Mars Science Laboratory:
• Mission goal is to determine whether Mars has ever had the conditions to support life
• Project costed at $2.5 billion; will see initial surface operations lasting two Earth years
• Onboard plutonium generators will deliver heat and electricity for at least 14 years
• 75 kg science payload more than 10 times as massive as those of earlier US Mars rovers
• Equipped with tools to brush and drill into rocks, to scoop up, sort and sieve samples
• Variety of analytical techniques to discern chemistry in rocks, soil and atmosphere
• Will try to make first definitive identification of organic (carbon-rich) compounds
• Even carries a laser to zap rocks; beam will identify atomic elements in rocks