This conjunction, as it is known, plays havoc with communications and the robot was forced to park up while the celestial mechanics took their course. But the ability to send commands has now been restored, and scientists have a heavy schedule of tasks they want the rover to work through.

The vehicle is currently sitting in a small depression on the floor of Gale Crater known as Yellowknife Bay. Just before conjunction, it drilled into a mudstone in a rock unit referred to as Sheepbed and found further compelling evidence for a watery past in Gale - sediments that possibly once formed a lakebed.

Curiosity is due to turn its drill again in this mudstone for further analysis before climbing out of Yellowknife Bay and heading for the crater's big central mountain, Aeolis Mons (Mount Sharp).

But almost as soon as it starts that journey, the robot is going to stop at some of the most spectacular rocks seen so far on the mission.

Scientists have mentioned the so-called Shaler outcrop but haven't yet spoken about it in great detail.

Shaler is a classic example of cross-stratification - a structure produced from thin, inclined layers of sediment.

You'll have seen examples in a river or on a beach.

The turbulent flow of water creates undulations in the bed sediments - a series of ripples or dunes that slowly migrate in the direction of the water current.

The sediment grains bouncing along the bed get pushed up the rearward-facing slope (stoss) and then avalanche down the other side (lee).

As they cascade downwards, they form discrete layers that can be preserved over geological time as laminations in the rock.

If you look at the pictures of Shaler taken by Curiosity, you can see how subsequent erosion has taken its toll on this preserved bedform. Layers just a few millimetres thick are now falling out. Thin plates of rock are strewn over the ground.

For anyone about to begin their study of geology, cross-stratification, or cross-bedding, will be one of the first topics to be covered in "sedimentary processes", and Shaler is a beautiful example.

"It's textbook; you could use the Shaler pictures of cross-bedding in an intro-textbook," Prof John Grotzinger, the project scientist on the Curiosity mission, told me.

"For a while Shaler really was a contender to drill. We were discussing it as a team and then we drove down into Sheepbed and thought 'wow, well let's put Shaler off to the side'."

But scientists will now get a chance to study Shaler in more detail in the coming weeks, using the rover's cameras and survey instruments.

They're keen to establish for sure how those thin layers were built.

At first glance, it might seem obvious that it was through the action of flowing water (fluvial), but the Curiosity team needs to rule out the possibility that these rocks were deposited by the wind (aeolian) or by some kind of surge, such as the fast-moving clouds of gas and rock that will often plummet down the sides of particular types of volcano (a pyroclastic surge).

"Aeolian. That's the one you always have to falsify on Mars because it's a windy planet," says Prof Grotzinger.

This can be done by looking at the size of the rock grains in the layers; and from the pictures taken of Shaler on the way into Yellowknife Bay, it seems the particles are simply too big to have been carried in the wind. Further imagery will confirm that.

There are ways to discount the base surge idea, also, explains Dr Lauren Edgar from Arizona State University.

"If you're migrating faster than you're accumulating, you just preserve the lee side because you're eroding on that stoss side. However, in a pyroclastic surge environment, you often have high rates of accumulation relative to migration, so as the bedform is migrating it is also rapidly accumulating more sediment. This means you tend to get the full stoss-side and lee-side preserved," she told BBC News.

Another check is to look for a diversity of flow directions. A surge deposition will tend to move radially away from a point source. Cross-stratification from water currents, on the other hand, will likely show movement in assorted directions.

To be honest, it's hard to think where a surge might have come from in Gale. There are no volcanoes around.

But Curiosity should nail all this with its return visit to Shaler.

Here's the really clever thing, though, I think. Cross-stratification is one of those rock structures that is so well understood, you can use it to pull out some amazing information about the past environment in which it occurred.

I've mentioned the direction of flow, but you can also determine the depth of the water and the speed of the water - not precisely, but to a good approximation.

Explore the Red Planet with Nasa's robot

Ponder that for a moment. That's information about an environment that existed on another planet millions of kilometres away.

"The other really nice thing," says Prof Sanjeev Gupta, a Curiosity science team-member from Imperial College London, "is that what you're recording at Shaler is perhaps just a few minutes to hours of migration in those dunes, and then that activity has been preserved for billions of years. That's stunning."

Edgar, Grotzinger and Gupta presented their latest thinking about Shaler on a poster at the recent European Geosciences Union General Assembly. Two of their colleagues on the work have some particularly nice web resources related to cross-stratification.

Prof Dawn Sumner from the University of California at Davis describes how the layers are built in a YouTube video. Dr Dave Rubin, at the US Geological Survey, has a collection of animations to show the different forms. And click here to see a tank experiment. Watch the ripples migrate into view from the left.

Finally, listen out for Sanjeev Gupta on the BBC's The Life Scientific next week. He'll be talking about Mars with Jim Al-Khalili.

It has also mapped the distribution of all the matter in the cosmos.

This was done by analysing the subtle distortions in the ancient light introduced as it passed by the matter.

The effect is a direct consequence of Einstein's theory of general relativity which tells us that space is warped by the presence of mass.

Prof Simon White likens it to the way light is bent as it passes through the lumpiness of an old glass window pane.

"If you know what you're looking at outside, you can use the distortions to say something about the glass," the Planck researcher said.

"There have been 'gravitational lensing' detections before over small areas, but this is the first time we've been able to do this kind of thing over the whole sky," he told BBC News.

The new map is a smart byproduct of the European Space Agency (Esa) telescope's main mission which is to survey the Cosmic Microwave Background, or CMB - a pervasive but faint glow of long-wavelength radiation that comes to us from the very edge of the observable Universe.

That light essentially carries a record of all the intervening structure it has encountered on its journey.

What you see in the map on this page, split across the two hemispheres of the sky, is the sum of all the matter/mass along the line of sight.

Red denotes those regions where there is more matter/mass than average; and blue denotes regions where there is less than average.

The white edging in the North/South projections is the plane of our Milky Way Galaxy.

This great mass of stars makes it impossible to discern the delicate gravitationally lensed distortions and the region is simply masked out.

The map is a very complex thing to produce, and reflects not only the extraordinary sensitivity and resolution of Planck but also the immense sophistication now possible in the statistical analysis of the telescope's data.

Scientists have checked the map against the distribution of matter obtained by other means.

In the near Universe, for example, it should fit with the detailed information we now have on the way clusters of galaxies are dotted across the sky. And it does.

For the more distant parts of the Universe, Planck itself can do the test. It can use its High Frequency Instrument to look for the infrared emission from dust that is warmed by stars associated with far-off galaxies.

The pattern in this light acts as a kind of proxy for the history of star formation, and therefore a history of structure in the cosmos. Again, it agrees well with what the new Planck map is telling us about the distribution of matter/mass.

Of course, it is thanks to Planck that we now know there is slightly more "stuff" out there than we thought, even if most of it is in a form beyond direct observation.

The analysis of the CMB data, released last Thursday, indicates that only 15.5% of the Universe's matter is what we would call "normal" - that is, the atomic material from which planets, stars and galaxies are built.

The rest (84.5%) is "dark matter" whose precise nature currently eludes scientific description.

The map at the top of this page makes no distinction. It is an integration of both normal and dark matter.

Planck can, however, be used to find a lot of previously unobserved regions of normal matter. These are large galaxy clusters.

They are identified using another clever trick named after the two Soviet physicists who proposed it in the 1960s.

Rashid Sunyaev and Yakov Zel'dovich said that a small fraction of the CMB light particles, or photons, should get a little kick in energy when they pass through the hot gas found in big clusters.

Once more, the effect is subtle but very characteristic, and Planck has used this Sunyaev-Zel'dovich method to catalogue more than 1,000 big cluster candidates, many of which had not previously been on the books.

"Planck is a discovery machine," the Esa project scientist Dr Jan Tauber told BBC News. "The data is now out there and people will really start to dig into it. There are a lot of scientists inside the Planck Collaboration but there are many more that are outside. They are going to find some great new uses for the data."

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American Nobel Laureate John Mather believes the bar has been set very high for the European Space Agency's (Esa) Planck surveyor.

The satellite was launched in 2009 to make temperature maps of the sky, and on Thursday this data will finally be released to the worldwide scientific community.

There is great hope that Planck will be able to tell us what happened in the first fractions of a second after the Big Bang when the Universe that we can observe today occupied almost no space at all. And by fractions, we mean about a millionth of a billionth, of a billionth, of a billionth of a second after it all got going.

To get at this information, Planck has sampled the "oldest light" in the cosmos - the light that was finally allowed to spread out across space once the Universe had cooled sufficiently to permit the formation of hydrogen atoms.

Before that time, about 375,000 years into the life of the cosmos, conditions would have been so hot that all the light would have been bounced around and trapped in a fog of ionised matter. The Universe would have been opaque.

The "fossil" light is still evident today. It bathes the Earth in a near-uniform glow which, thanks to the expansion of the Universe, can now be found at microwave frequencies.

Its temperature profile has also dropped to just 2.7 degrees above absolute zero, with only a minute excess of warmth or cold either side of this signal depending on where you look on the sky.

These temperature fluctuations reflect differences in the density of matter when the light parted company and set out on its journey.

American satellites, including Mather's historic COBE mission in 1989, have already extracted astonishing insights from this Cosmic Microwave Background (CMB) radiation. These include refined estimates for:

"Planck has the extra sensitivity and resolution to retrieve yet more information," the Nasa scientist told BBC News. "The question then is: have they done the right things with the data?"

The European team behind Planck will present maps of the sky in nine frequencies - six more than COBE, and three more than its US successor, WMAP, which flew in 2001.

This broader sweep was designed to give the Esa mission a sharper, cleaner view of the CMB, and the minuscule fluctuations in temperature that are seen around that mean of 2.7 kelvins (-270C).

It is with this keener vision that Planck will endeavour to find "some new phenomenon", not at 375,000 years after the Big Bang but long before then.

Information encoded in the satellite's maps should also tell us about "inflation", the faster than light expansion that cosmologists believe the Universe may have experienced in its first fleeting moments.

Watch Planck's breathtaking launch

How do we know the Big Bang happened?

Inflation has become the accepted add-on to Big Bang theory in the past 30 years, even though its physics is highly speculative. Scientists like the concept because it would explain some important observations, not least the geometry of space - a superluminal expansion could have stretched everything until it was flat. The tiny quantum fluctuations that drove the expansion could also have given rise to small variations in the amount of matter from one place to another, seeding the later gravitational growth of stars and galaxies.

But there are numerous models for how inflation might have worked. They cannot all be right.

"What we need to do now is back some of these models into the corner, and Planck can help us do that," said Prof Andrew Jaffe from Imperial College London.

One of the ways scientists study the CMB is by subjecting the warm and cold spots in the radiation to a detailed statistical analysis, examining the deviations in temperature as a function of their size on the sky - their angular scale.

This produces a characteristic wiggle on a graph, a so-called power spectrum, which can then be matched against theoretical expectation.

Inflation - if it happened - predicts that this spectrum should be ever so slightly tilted; and WMAP has seen evidence for this.

"It's not yet very precisely determined but this is one of the instances in which Planck will make a real difference," explained Prof Bruce Partridge of Haverford College, Philadelphia.

"Because it has high resolution, it is spanning a wide range of angular scale. And what you want to do to see a slight tilt with respect to angular scale is to have as large a lever arm as possible, and Planck will do that," he told BBC News.

Another prediction of inflation is that the CMB should be gaussian. If you pick up all the temperature data points in the sky map and put them in histogram, you should get a nice bell curve.

"If it's not gaussian then we have to re-think inflation or maybe inflation is more complicated than the simplest models suggest," said Prof Marc Kamionkowski from Johns Hopkins University, Baltimore.

Planck's capabilities mean it will provide one of the best checks yet for non-gaussianity.

The ultimate test, however, would be to look for a special signal in the CMB referred to as B-Modes.

Most models of inflation suggest the expansion would have been accompanied by ripples of gravitational energy. These should have been imprinted on the fossil light in its polarisation.

Even if they are there, these B-modes will be very hard to detect, and the Planck team does not intend to make a statement on the issue until a further year of analysis has been completed.

Nonetheless, Thursday's announcement is likely to make some important statements on inflationary tests. A whole swathe of models will probably be confined to the bin at the end of the day.

Esa's Planck project scientist, Dr Jan Tauber, will not be drawn on the findings before the release in Paris. Asked to describe the new temperature maps, he says merely: "They're beautiful."

Since 2009, the billion-euro Herschel telescope has been unravelling the complexities of star birth and galaxy evolution.

But its instruments employ special detectors that need to be chilled to fantastically low temperatures.

The helium refrigerant that does this job will run out in a few weeks and when it does, Herschel will go blind.

The coming demise of the telescope is no surprise. It is occurring just as was forecast at the start of the mission, almost to the month.

Researchers are now busy running through a final list of observations, acquiring as many images as they can in the time left available.

Already, thousands of pictures have been deposited in the Herschel archive, which is set to become a key reference source for decades into the future.

"I think there is a consensus in the community that Herschel has been a tremendous success and that we have made beautiful observations," Esa project scientist Dr Göran Pilbratt told BBC News.

The telescope was launched almost four years ago and sent to an observing position 1.5 million km from Earth.

It was equipped with a 3.5m mirror - the largest monolithic mirror ever flown - and three state-of-the-art instruments sensitive to long wavelengths of light, in the far-infrared and sub-millimetre range (55 to 672 microns).

This technology has allowed Herschel to study the processes at play as large clouds of gas and dust collapse to form new stars. Its deep vision has also enabled scientists to trace the story of how galaxies have changed through cosmic time.

But the design of the instruments, and in particular of their detectors, has required Herschel be operated close to absolute zero (-273.15C).

Like hot tea behind a bin bag - how does Herschel let us see hidden stars?

This has been achieved with the aid of a cooling system run on superfluid helium, more than 2,000 litres of which were loaded into the telescope at launch.

The cryogen has gradually boiled off during the course of the mission, and the latest calculation from engineers is that it will be gone entirely sometime in the final two weeks of this month.

Once the detectors start to warm from their ultra-frigid state, they will stop working. The end, when it happens, will be quite sudden.

Those astronomers in the queue to use Herschel at that moment will no doubt be disappointed, but also philosophical: observing time was allocated on the basis that the opportunity could not be guaranteed as the mission moved into its end phase.

Some engineering tests will be conducted on the telescope in April. The Esa operations team will then put the satellite into a slow drift around the Sun before ceasing all communications.

Prof Matt Griffin, from Cardiff University, is team leader on the Spire instrument, which is sensitive to some of the longest wavelengths. He said the telescope had exceeded all expectations.

"It will be a sad day when it makes its last observation, but the data that it has collected during its lifetime will keep astronomers busy for years," he told BBC News.

"For the next three years, the Spire team will work hard to put all Spire data into the best possible condition to be as easy as possible to access and to use in the future.

"Amongst Herschel's most exciting results have been the detection of many thousands of distant star-forming galaxies that are helping us understand how galaxies formed and evolved over cosmic time, and the mapping out in our own galaxy of the filaments and cores that are the sites of new suns being formed today."

Known as Strand-1, the British-built spacecraft will be fully controlled by a Google Nexus device during part of its six-month mission in orbit.

The project has been led from the Surrey Space Centre (SSC) and Surrey Satellite Technology Limited (SSTL), both in Guildford.

Strand-1 was packed off to India this week for a rocket launch that is likely to occur at the end of the month.

The Nexus One has not been physically modified in anyway and will be an interesting test of everyday consumer electronics, says Dr Chris Bridges, SSC's lead engineer on the venture.

"We haven't gutted the Nexus. We've done lots and lots of tests on it; we've put our own software on it. But we've essentially got a regular phone, connected up the USB to it and put it in the satellite," he told BBC News.

"This is about looking at the latest technologies that are out there and seeing whether they are up to the harsh challenge of space."

The smartphone will fly pressed up against a side panel of the 30cm-long, 4.3kg "cubesat".

This will allow its 5-megapixel camera to look out through a hole and take pictures of the Earth and the Moon.

Strand is an acronym that stands for Surrey Training Research and Nanosatellite Demonstration. It is part of a quest to find new thinking and new technologies.

SSTL, which is a world leader in the production of small commercial spacecraft, hopes some of the Strand lessons can filter through to its more traditional products.

For the first part of the mission, the satellite will be controlled by a new high-speed Linux-based cubesat computer developed at SSC, which is part of the University of Surrey.

An important goal during these early weeks will be to test two innovative propulsion systems.

One uses the ejection of a water-alcohol mixture to provide thrust. The system is tiny but has a grand name - Warp Drive (Water Alcohol Resisto-jet Propulsion De-orbit Re-entry Velocity Experiment).

The second propulsion technology on Strand is its pulsed plasma thrusters. These use an electric current to heat and ablate a material, producing a charged gas that can then be accelerated in one direction in a magnetic field to push the cubesat in the other direction.

Both propulsion systems produce only small amounts of thrust but are very efficient in terms of how much "propellant" they consume.

Assuming the mission goes well, the team wants eventually, gradually to turn the operation of Strand-1 over to the Nexus.

Although phones, or parts of phones, have been sent into space before, running an entire satellite through such a device has not been tried previously.

The Strand Nexus also carries a number of "apps" for science and outreach.

One of them has garnered quite a bit of publicity already. This is the "Scream in Space" app suggested by Cambridge University students.

It will see the Nexus phone play videos of people screaming to test the famous Alien movie poster statement that "In space, no-one can hear you scream". A camera looking at the phone's own display will record the likely silent screaming faces in the videos.

This alternate camera will also show the satellite's telemetry rolling across the screen for another App, and there is a simple experiment also to sense the magnetic environment in space using the Nexus' own onboard magnetometer.

"It's not likely that we are going to pick up a smartphone, as is, and put it at the core of our $30m satellites," said SSTL's head of science, Doug Liddle.

"But what is likely is that we'll pick up the approach we've used. This could be some of the phone's components, such as its wi-fi chip or Arm processor; we might be able to re-use those.

"Consider also the Android Apps (open-source) approach to developing software - that might be something that could be transplanted into our way of doing things in the future.

"It would mean that instead of having a small, niche group of spacecraft flight-software developers, you could suddenly call on a global community of app developers to help you design control or telemetry-handling systems for spacecraft."

Strand-1 is booked to fly on the Indian space agency's (Isro) Polar Satellite Launch Vehicle (PSLV) on 25 February.

It is a piggyback passenger on the rocket. The main payload is a prestige Franco-Indian altimetry mission, Saral, which will measure sea-surface height. SSTL also has one of its larger platforms aboard called Sapphire, which will do space surveillance for the Canadians.

The Strand-1 cubesat will be pinged out from a spring-loaded pod mechanism at an altitude of 785km once the rocket's main business has been completed.

The terms of its UK Space Agency licence mean Strand must be brought out of the sky at the end of its mission in a timely fashion to avoid adding to the junk in orbit.

A Strand-2 is already in development. This will see two cubesats use the motion-sensing technology in Microsoft's XBox Kinect devices to locate each other in space and dock together.

And to get a true sense of any trends, you really need those measurements to be long-term and unceasing.

Preferably, you use the same type of instrument to make the observations, and when, inevitably, you're required to replace aging equipment, you do so in such a way that the new system can be cross-calibrated with the old.

Few Earth observation programmes get as close to this gold standard as Landsat, the cooperative space mission run by US space agency (Nasa) and the US Geological Survey.

For 40 years now, the Nasa/USGS satellites have maintained a permanent eye on Earth.

It was during the Apollo preparations - when astronauts would also take pictures of their home planet as they tested their Moon technologies - that the idea was born for a dedicated imaging system to observe the Earth.

It led to the development of the Earth Resources Technology Satellite (ERTS), launched on 23 July 1972 and operated for six years. Subsequent platforms picked up the baton. Today, Landsat-7 maintains the watch, with its successor, Landsat-8, being readied for lift-off next month.

The latest incarnation will go up from California's Vandenberg Air Force base on an Atlas rocket, and, after a few weeks of checks, assume the lead role of imaging the planet from an altitude of 705km.

The Landsat spacecraft view the Earth in visible and infrared wavelengths, and track details as small as 30m across.

It's true there are imaging sensors up there now that will return pictures of Earth with far better resolutions (in the tens of centimetres), but for the job Landsat is trying to do, the 30m/pixel view is perfect.

Over its 40-year history, Landsat has catalogued the growth of the megacities, the spread of farming and the changing outlines of coasts, forests, deserts and glaciers. It has monitored fires and volcanic eruptions. It has even detailed the behaviours of Antarctic penguins and North American beetles.

"One [application] that we're particularly proud of is the use of something we call the thermal band," explained Matt Larsen, the associate director for climate and land-use change at the USGS.

"This is a technique by which we can estimate the temperature of the surface of the Earth from the sensors on the Landsat satellite, and from that we can measure evapotranspiration (the conversion of water to water vapour).

"Why do we care about that? That's a key part of agricultural activity, and in the western US where we have a huge amount of land in irrigated agriculture, it allows us to better understand how much water we are using, how much water we need and how that might be affected in the future because of changing stream flows because of changing temperatures," he told the BBC World Service's Science In Action programme (listen to our feature).

Landsat-8 will carry an additional thermal band that will lead to more precise measurements.

The uses of Landsat data really are innumerable.

Paul Donald, a conservation scientist with the UK's Royal Society for the Protection of Birds (RSPB), gives a great example of how these pictures can be used to understand the geographical distribution of very poorly known avian species. You cannot see the birds from space, obviously, but you can map their likely habitat.

"One of the ways we can do this is to use a modelling technique, where we take Landsat data and we match that with areas where we know the birds are; and that will then give us a very good description of where the bird may be where people have never even been to look for it," he told us.

"The results have been extraordinary. We've generated maps using Landsat imagery which have predicted areas we never thought suitable for this bird. We've gone there, and we've found the bird."

Landsat-8 is more formally called the Landsat Data Continuity Mission (LDCM). This mouthful reflects the rather tortured route the mission had to take to get budget approval. It's a perennial problem for Earth observation missions - getting a timely sign-off from the politicians so that an enduring presence in orbit can be maintained. Even with Landsat, it is as if each satellite was born an only child, and the next mission had to fight for justification as if there had been no heritage.

Nasa, USGS and the Federal Office of Management and Budget (OMB) are now seeking a long-term solution that would see Landsat-9 and all following spacecraft arrive on a predictable track.

It is the sort of assurance Earth observation seeks in Europe, also. At the end of this year, the European Space Agency will start to roll out the multi-billion-euro Sentinel fleet of satellites, which aim to echo the Landsat philosophy but with many more types of sensor. However, even as the first mission is prepared for launch, politicians are still arguing over how the project should be funded.

Eugene Cernan, Ron Evans and Harrison "Jack" Schmitt were the last crew to visit Earth's satellite, with Cernan and Schmitt becoming the 11th and 12th humans to step on to its surface.

And then, as a species, we retreated.

Attending the American Geophysical Union (AGU) Fall Meeting these past few days has reminded me just how significant the Moon remains in terms of its science.

President Obama rejected it as a potential destination for future exploration ("We've been there before") in preference for asteroids.

But if you look at what we've learnt in recent years from the fleet of orbiters sent to circle the body, it just underlines that we've really only just scratched the surface.

The release of the new Grail gravity data set has probably been the stand-out moment of this AGU meeting, which brings together the world's leading Earth and planetary researchers.

It's not every day that information is placed before the scientific community that is truly transformative but the gravity maps may well fall into this class.

There's been quite a bit of talk of having to rewrite the textbooks.

The data has certainly impressed Schmitt, who continues to take a very close interest in lunar geology. Remember, he was the sole Apollo astronaut to fly as a scientist, not as a test pilot.

He's been back at AGU this week and his fascination with the Moon remains undimmed. He still thinks it's an important place for astronauts to visit.

"No question about it," he told me. "Whether you think about the science of the Moon or the resources of the Moon, or its relationship to accelerating our progress on to Mars.

"I'm not a big fan of asteroids [as a destination]. I think we have most of the science from meteorites, and asteroids are going to be very difficult to work around because of the very low gravity field.

"We would figure out how to do it, but I think to put together a programme to visit an asteroid when the ultimate aim is to get to Mars, and you have a satellite only three days away that has a great deal of science to offer as well as resources to offer, I think an asteroid is a diversion."

So, assuming the capability and budget existed, where on the Moon would he want to put boots?

Quick as a flash, he came back: "I'd go to South Pole Aitken Basin with significant mobility."

South Pole Aitken, or SPA, is the Moon's biggest and oldest impact feature, and is found on the far side.

It's some 2,500km across and reaches deep into the crust. SPA is suspected to have been created during a great bombardment of the inner Solar System by rocky debris that was disturbed and thrown our way when the giant planets underwent an adjustment in their orbits. That's one idea, anyway.

Scientists would dearly like to tie down the timing of this cataclysm, and getting rocks from SPA is the way to do that.

It would also probably tell us something about ourselves, says Brad Jolliff, a lunar expert from Washington University, St Louis.

"The earliest life on Earth looks to be around the time of 3.8bn years ago. That's about the time this cataclysm stopped.

"The earlier period on Earth is really largely gone. This is called the Hadean Eon. From that time, the oldest materials we have are tiny crystals, bits of the mineral zircon.

"It's a resistant mineral so the rock can be melted and eroded, and all we have left are these zircons. So we can see [something of] that earlier time. But we don't really have any rocks from that time. So having the lunar samples, which nearly all come from that time period, gives us a snapshot that we can't see on Earth."

Putting astronauts down on the far side to do field work is obviously the dream. A more realistic near-term scenario is a venture that returns SPA rocks to Earth robotically, something Jolliff has long advocated.

"I would absolutely love to see astronauts there, and it will happen someday. We'll have astronauts in various places on the Moon. But in the foreseeable future it's just not in the realm of the fiscal reality that we're faced with."

The big European vehicle throws up everything from three-tonne TV satellites to the 20-tonne ATV space truck used to resupply astronauts on the ISS.

Half of the major telecommunications platforms lofted every year ride the European battlehorse.

But as good as it is, Ariane is under pressure. Competitors are circling and changes are needed if the vehicle is to retain its benchmark status.

We got a glimpse this week of where the rocket is heading after research ministers approved a 600m euros programme of developments at their European Space Agency council meeting in Naples.

Work will continue to give Ariane 5 a major upgrade, to provide it with a more powerful upper-stage engine that will also have a stop-start capability.

These modifications will enable the vehicle to better optimize its payload capacity for heavier, more lucrative satellite customers - and also to offer a broader range of orbits to those clients.

This Mid-Life Evolution (ME), as it is known, is now scheduled to fly in 2017/18.

But ministers have not stopped there. At the same time, they want to see detailed studies to define the next generation rocket - an Ariane 6.

Early thinking is that this will be a smaller rocket than Ariane 5 with a modular design capable of lifting one satellite at a time weighing from three to 6.5 tonnes.

A final pronouncement on whether to proceed with the project is likely in 2014. A maiden flight could occur in 2021/22.

The Esa ministerial council outcome was warmly welcomed by Jean-Yves Le Gall, the man who heads up Arianespace, the commercial operator of Europe's big rocket.

"It was a great success," he told me. "Now we have a shining future. The most important consequence of the ministerial decisions is that our vision is now much further forward than it was before. Before we had just to launch Ariane 5. Now we have a reason which is launching Ariane 6 in 10 years' time, and I can tell you we have a lot of young people here who are very excited."

There's been a lot of fuss recently about the impact that aggressive competitors will have on Ariane's market share.

You may have seen my interview last week with SpaceX chief executive Elon Musk where he said Ariane 5 had "no chance" in the face of his new Falcon 9 and Falcon Heavy rockets. The European vehicle could get nowhere near his prices, the entrepreneur contended.

Certainly, there've been plenty of people queuing up to echo the voice of doom on Ariane. French politicians, for example, who visited the SpaceX factory in California came away wanting a direct move to Ariane 6. The successor vehicle is expected to incorporate much cheaper components and fabrication methods than the current rocket, or indeed Ariane 5ME.

But Le Gall calls for cooler heads. Ariane 5 is not about to fall away. The rocket has a proven track record of reliability, and in the launch business that is everything.

"Some of our competitors, for instance Proton, are suffering almost one failure every year, which is huge. And I want to remind people that behind us we have 52 successes in a row.

"And there are other competitors, such as SpaceX, who speak a lot but have not yet launched a lot, and I think if you really want to exist in this business you must be very humble because it's a difficult business, and in my opinion you can only really speak when you have an excellent track record."

Le Gall accepts that Ariane 5 is pricey, but says he has fulfilled his commitment to constrain price by reducing the cost of operating the vehicle's spaceport in French Guiana by 20%.

But there is no magic formula that will reduce the industrial cost of producing the existing Ariane 5.

Unlike the SpaceX Falcons which are made in one place (more than 70% of a vehicle by value is made in the single factory), Arianes by definition are made across Europe. A dozen countries are involved in the Ariane 5ME project. This community approach must change long-term, and it is likely that the Ariane 6, when it arrives, will have an industrial base pretty much confined to France and Germany.

That may well offend some Esa member states but it's a fact of life that research ministers will have to grapple with when they gather again in 2014 to pronounce on the next phase of Ariane 6 development.

They should also have a clearer idea then of what this rocket should look like. It seems obvious, but Esa director general Jean-Jacques Dordain has been asking satellite operators precisely what they want.

"I've asked them, 'what is the launcher that you dream of?'; and they've given me their dreams," he told reporters in Naples.

"What I wish to do now is tell the launcher industry in Europe, 'OK, can you now fulfil the dreams of the customers?'.

"The customers want, obviously, the most reliable vehicle in the world - and at least on that, Ariane 5 is much more reliable than a lot of other vehicles. They want a launcher that is available, and that will launch between 3-3.5 tonnes and 6-6.5t. And, number four, they want a rocket that is cheaper than Proton and Falcon 9. This is the cahier des charges (specification base)."

On one side, it's baked by the Sun, receiving some 14,000 watts per square metre, about 10 times what a spacecraft in orbit around Earth would receive.

But the spacecraft is also then baked on the other side because the planet itself is a "hot potato", where surface temperatures can reach 470C.

It's a hellish nightmare and designing a probe that could handle this extreme environment very nearly flummoxed Europe's best engineers.

The BepiColombo mission's difficulty in arriving at technical solutions to meet the thermal challenge greatly increased costs and brought the venture perilously close to cancellation.

Bepi is now progressing well through its construction phase - albeit way behind on the original schedule - and should be ready for launch in 2015.

The European Space Agency (Esa) mission is a joint venture with Jaxa, the Japanese national space agency.

Europe is providing a Mercury Planetary Orbiter (MPO). This will carry 11 scientific instruments. It will fly in a polar orbit around the planet, imaging the surface, generating height profiles, and collecting data on surface composition and the wispy "atmosphere".

Japan's contribution is the Mercury Magnetospheric Orbiter (MMO). This will have five instruments and will investigate the planet's magnetic field. Mercury, you will recall, is the only terrestrial planet (apart from Earth) to have global magnetic field.

The UK has a prominent role on the mission. Its engineers have been responsible for the construction of the MPO spacecraft's structure and propulsion system. British brains have also done the complex mission analysis to work out how to fly into the deep gravity well of the inner Solar System. BepiColombo will have to swing by Earth once, Venus twice, and Mercury four times to get itself into the right position to map the planet.

The image at the top of this page is the main structure of the MPO at the Astrium factory in Stevenage. It's being shipped this week to Thales Alenia Space in Turin for further fitting, including the installation of the European mission's 11 instruments.

The MPO has an unusual shape for a planetary probe but, again, that's a consequence of where it needs to operate. The long edge along the bottom will be the location for a big radiator that will be kept pointed away from the Sun at all times.

"We have lots and lots of heat pipes on board," explained Astrium spacecraft systems engineer Jess Marshall.

"These have a small amount of ammonia in them. This evaporates, whizzes up the tubes and then condenses at the radiator. Everything about this spacecraft is about staying cool.

"Bepi is unusual in that it will look white. Our spacecraft normally have a gold-coloured, multi-layered insulation. Bepi's insulation will have to be much more robust - it will be a lot thicker, a lot heavier. The white outer covering will reflect a lot of heat away, but we must be very careful also that there are no holes anywhere - no gaps - or that heat will creep in."

Many people's reaction to Mercury is that it is a bit of a dullard. Unlike Mars with its many Earth-like vistas, the inner world appears very one dimensional. The US Messenger probe now in orbit has gone a long way I think to countering that viewpoint.

It has thrown up many surprises and challenged our assumptions about what the closest planet to the Sun should be like.

Messenger has revealed Mercury's rich volcanic history. It has confirmed the existence of great lava plains, but also uncovered evidence for explosive volcanism.

The probe has identified lots of sulphur (2-4%) in the surface. That wasn't expected. Indeed, there are many more volatile substances in Mercury's surface than would be expected. They simply shouldn't be there in a planet that orbits so close to the Sun, or one that - according to the popular idea - was involved in a mighty collision that ripped away its upper-most layers. And then there are these dramatic hollows that have been discovered.

This strange pock-marked terrain is yet further evidence of the release of volatile material evaporating away into space.

"We're not quite sure yet what that material is yet," said Dr Dave Rothery. The Open University researcher is chief scientist on BepiColombo's Mercury Imaging X-ray Spectrometer (MIXS).

"[With Bepi] we'll have sufficiently high spatial resolution with the X-ray telescope to see what the elemental distribution is within these quite small hollowed areas. "Messenger can't do that - it has a much cruder, coarser resolution. So, we'll learn a lot more when we get a more sophisticated spacecraft there, but we already know it's an absolutely fascinating planet which is not doing what it ought to do.

"That's the joy of planetary exploration - you work out what you should expect to see to test your hypotheses and then you go there and find, 'crikey, this wasn't what we expected at all'.

"We've got to have a big re-think and until we understand how Mercury formed we won't understand how our own planet formed."

If you dig around the mission websites, you can find their "raw images" sections.

These indexes can be a little confusing to the uninitiated because the pictures rarely come with clear caption material, and you're not always sure what you are looking at. But I promise you, it can be a rewarding time browsing the unfiltered vistas from far-flung worlds. You'll often see things that only get mentioned by the big news organisations days later when they're given one carefully selected shot to publish.

And in the case of the Mars rover missions, these raw collections also allow anyone with the right software to start to build their own panoramas of the Red Planet.

I wanted to draw your attention to the work of Ken Kremer, a freelance science writer whose work can often be found at Universe Today, but at many other publications as well. Ken, with colleague Marco Di Lorenzo, has built a number of panoramas of Gale Crater that give us a wider perspective on the Curiosity vehicle's Martian home - literally.

The image at the top of this page was built from pictures acquired by the rover on the 85th Martian day of its mission (the middle of last week).

The self-portrait was stitched together from images captured by the "hand lens" on the end of the vehicle's robotic arm.

The large rise in the background is the big mountain in the centre of Gale Crater known as Mount Sharp. It is at the base of this peak that the rover expects to find some of the most interesting rocks during its mission, although it will be many months before it gets there.

It's a great panorama because it reminds me of those holiday pictures we've all taken with the landmark over the shoulder. "Wish you were here!"

One of my favourite panoramas from Ken is the one he's put together of Glenelg.

If you've been following the Curiosity mission you'll know this location was selected as the first prime science destination - it's where satellite imagery has indicated there is a junction of three distinct rock terrains.

Curiosity will trundle around this patch of ground looking for a candidate rock in which to drill. That activity should take place in the next few weeks.

You can follow Ken Kremer's work at his website. His pictures will also be featured in the PBS NOVA documentary on Curiosity called Ultimate Mars Challenge, which airs in the US next week on Wednesday (21:00 ET/PT).

And let me recommend, too, the Opportunity Mars rover's raw section, and that of the Cassini Saturn orbiter. The Cassini site has a useful FAQ that explains some of the oddities of wading through such collections.

And if you want to see what others are up to in terms of "citizen image processing", drop by the online forum unmannedspaceflight.com. Lots of mosaics are being shared there.

The Chancellor George Osborne has just told them they can now commit substantially more money to the intergovernmental organisation's projects.

Currently, the UK invests an average of £170m a year in Esa. This is going to rise to an average of £240m over the period from 2013/14 to 2017/18.

It is a significant uplift at a time when many other member states have been frantically stuffing their hands down the back of the sofa to find the cash just to pay their existing subscriptions.

This Naples Ministerial Council will be key in setting the priorities of the agency in this decade, and Britain has now indicated it wants to play a leading role - but with a very clear purpose: to spur economic growth at home.

The Chancellor George Osborne has just told them they can now commit substantially more money to the intergovernmental organisation's projects.

Currently, the UK invests an average of £170m a year in Esa. This is going to rise to an average of £240m over the period from 2013/14 to 2017/18.

It is a significant uplift at a time when many other member states have been frantically stuffing their hands down the back of the sofa to find the cash just to pay their existing subscriptions.

This Naples Ministerial Council will be key in setting the priorities of the agency in this decade, and Britain has now indicated it wants to play a leading role - but with a very clear purpose: to spur economic growth at home.

Many people think of Esa as a science organisation - and it is. But it is also a huge industrial programme. Each year it places contracts across Europe worth billions of euros; and the more money a member state puts into the Paris-based club, the more money that flows back to the home companies. And this is all hi-tech investment with proven multipliers, so the real return is even greater.

Take telecommunications satellites, for example. The UK's past investment in the Esa programme called Artes (Advanced Research in Telecommunications Systems) has generated an economic return for the UK of more than six to one.

The Astrium company at its Stevenage and Portsmouth centres has benefited most from this investment, and has become one of the world's leading suppliers of all those spacecraft up there that relay TV and phone calls around the globe. And this "upstream" activity has been followed by even more lucrative "downstream" businesses.

Inmarsat of London is the big daddy of mobile satellite communications services, and there are few more successful satellite TV companies in the world than British Sky Broadcasting.

As I've written before, government and industry in the UK now have a joint plan to push the space sector forward, and Science Minster David Willetts has been steadily working through a checklist that broadly follows the recommendations in the Space Innovation and Growth Strategy (S-IGS) published in 2010.

This document laid out the path it believed could take the UK from a position where it currently claims about 6% of the world market in space products and services to about 10% by 2030, creating perhaps 100,000 new hi-tech jobs in the process.

Key S-IGS recommendations implemented so far include the establishment of the UK Space Agency (UKSA) and a National Space Technology Programme. Government support for an innovative radar satellite called NovaSAR was a tick in the box that called for investment in Earth observation.

Other pluses included the International Space Innovation Centre (Isic) and the Catapult Centre in Space Applications set up at Harwell, Oxfordshire. These institutions are very much industry-focused and will seek to foster near and far ideas and bring them to market.

George Osbourne's announcement of extra money for Esa fulfils yet another of the S-IGS recommendations.

"The fact that the UK government is increasing its subscription to Esa programmes is a huge vote of confidence," said Inmarsat's Ruy Pinto, who is also the chairman of UKspace, the industry trade body.

"It indicates that industry and science have successfully made the case - that started with the S-IGS - for targeted investments into our sector because of the return we could make to the UK economy. We tick a lot of boxes with the government in terms of wealth creation, job creation, export growth, and in being technology and science-led."

You don't need to be a rocket scientist to work out where the UK delegation plans to put a sizeable chunk of its elevated subscription in Naples. It will go into telecoms projects like Artes to develop the next generation of satellites.

Esa itself is so impressed by the UK's commitment that it is likely to move its telecommunications and integrated applications HQ from its big technical centre in Holland to its newly opened facility in Harwell.

This corner of Oxfordshire is becoming quite a magnet for new space activity.

Sadly, the issue is not "if" but "when" the next tremor will occur in L'Aquila. But it is simply not possible to be precise about the timing of future events. Science does not possess that power. The best it can do is talk in terms of risk and of probabilities, the likelihood that an event of a certain magnitude might occur at some point in the future.

The decision to prosecute some of Italy's leading geophysicists drew condemnation from around the world. The scholarly bodies said it had been beyond anyone to predict exactly what would happen in L'Aquila on 6 April 2009.

But the authorities who pursued the seven defendants stressed that the case was never about the power of prediction - it was about what was interpreted to be an inadequate characterisation of the risks; of being misleadingly reassuring about the dangers that faced their city.

Nonetheless, the verdicts will come as a shock to all researchers in Italy whose expertise lies in the field of assessing natural hazards. Their pronouncements will be scrutinised as never before, and their fear will be that they too could find themselves embroiled in legal action over statements that are inherently uncertain.

It starts with an object called Jake.

I wrote last week about a dark, pyramid-shaped igneous rock on the Red Planet that had just been investigated by Nasa's Curiosity rover.

It certainly looked cool and it caught the imagination because my report subsequently clocked more hits that day than any other news story on the BBC. Never mind wars, politics and the economy - everyone, it seemed, wanted to find out more about this unusual, 25cm-high rock sitting in a crater almost 300 million km from Earth.

When Curiosity approached the volcanic rock, there was never really any expectation that it would pique great excitement.

It looked like just another dull piece of basalt, so much of which litters the Martian surface. But the science team on Curiosity needed a target to try out the first close-contact work using the rover's arm-held X-ray-spectrometer, APXS. So the dark pyramid was chosen and informally given the name Jake Matijevic in honour of a recently deceased rover engineer.

The results of the investigation by APXS, and the rover's laser instrument, ChemCam, revealed the rock to be anything but dull.

The science team likened its chemistry to some relatively rare but well-studied alkaline rocks on Earth found on oceanic islands such as Hawaii and the Azores, and also in rift zones like the Rio Grande. On Earth, such rocks typically form from relatively water-rich magmas that have cooled slowly at raised pressures.

The Curiosity team compared their formation to the fractionation that occurred in the old colonial method of making apple jack liquor. This process saw barrels of cider left outside in winter to partially freeze. As the barrels iced up, they would concentrate the apple-flavoured liquor.

Likewise, cooling magmas under pressure will crystallise and concentrate residual fluids. Jake was a consequence of those residual fluids, eventually solidifying just inside a Martian volcano or in a lava flow.

Well, everyone loved the apple jack analogy but a number of you got in touch to ask for the exact classification of the rock.

"What scientific name are they giving to the lithology?" you wanted to know.

And so I went back to rover scientist and petrologist Prof Ed Stolper, who had presented the Jake results. Could he provide one?

This was not straightforward, he explained. Although APXS and ChemCam will tell you which chemical elements are present, they don't tell you how precisely those atoms are arranged into the crystalline structures that make up the rock, and both this mineralogy and the chemical composition are ideally needed to assign a rock name.

So there's a bit of guesstimation going on here. From the chemical composition, you have to work out the most likely mineralogy.

As mentioned, Jake has much higher amounts of alkali elements, metals such as sodium and potassium, than previously analysed Martian rocks. And that has Prof Stolper and the rest of the rover science team leaning (with a lot of caveats) towards a classification that sits on a well-established sequence of alkaline igneous rocks - one that goes by the name "mugearite".

And this is where we come to the great coincidence.

If you've been following the Curiosity rover story closely, you'll know that scientists on the mission have been using names taken from Canada's Northwest Territories to label the places the rover is visiting.

The Canadian north-west has some ancient rock formations, similar in age, we think, to those found in Gale Crater, Curiosity's landing site.

Discover more about the planets

The naming system makes it easy for everyone to understand what's being discussed when a particular location comes up in conversation. So, for example, the rover is currently making its way to a place everyone is referring to as Glenelg.

This name is taken from a particular rock unit in the Northwest Territories, but it has an even older lineage - one that goes back to a small Highland settlement in Scotland.

This version of Glenelg is found on the western edge of the mainland, right by the water channel separating the Isle of Skye from the rest of Scotland.

Now read what Prof Stolper told me: "The 'type locality' for mugearite [i.e. the place the rock was first discovered, or at least defined as a distinctive rock type] is Mugeary, which turns out to be on Skye only 25 miles west of Glenelg.

"The fellow who named the rock type [in 1904] was Alfred Harker, the most influential British petrographer/petrologist of the first third (or so) of the 20th Century.

"Given the nearness of Mugeary and Glenelg, I consider it to be a great cosmic coincidence that on its way to Glenelg, the Curiosity rover found a rock that can legitimately be called a mugearite!"

Life has a habit of throwing up such remarkable connections. Glenelg was identified and named on Mars four weeks before Jake was even seen.

Curiosity only landed on the Red Planet in August but already it has returned some truly exciting science. And to think we have another couple of years at least to go on this mission.

The pedants will no doubt point out that Felix Baumgartner's attempt to make the highest ever skydive from 120,000ft (36.5km) is nowhere near space; and of course, they'd be right - the so-called Karman line is judged to be at about 100km (328,000ft). But this kind of misses the point.

At the altitude the Austrian daredevil intends to leap out of his capsule, the air pressure is less than 2% of what it is at sea level. He'll be jumping into a near vacuum. He's all but in space.

It's been a long road for Baumgartner. He first discussed with his sponsors Red Bull the idea of breaking Col Joe Kittinger's 52-year-old parachute mark back in 2005.

Since then, he's had to battle technical and budgetary challenges to make it happen, calling on the expertise of a top-notch team - Kittinger included - to pull him through.

The 43-year-old now needs not so much as a fair wind but next to zero wind to launch his "monster balloon" and capsule. He should realise his dream in the coming days.

"It's enormously difficult to launch a balloon this big," team meteorologist Don Day told me.

"When it comes down to launching Felix, it'll all be about wind speed and wind direction. We need calm to 3mph, from the ground up to about 250m. If it's any more than that, our launch crane cannot keep up. But right now, Tuesday's looking good."

Baumgartner will try to break four records here in Roswell, New Mexico:

Highest ever parachute jump. On 16 August 1960, the US Air Force pilot Kittinger jumped from 102,800ft (31.3km). Baumgartner will use a helium balloon with 10 times the volume to get another 18,000ft (5.5km) higher into the sky. The polyethylene envelope is an extraordinary thing. It will be 55 storeys high on lift-off, and as wide as a football field when fully inflated in the stratosphere; but the membrane itself will be just 20 microns thick. Think of the plastic bag in which you collect your dry cleaning.

First human to break the sound barrier unaided by a vehicle. Kittinger reached 614mph (988km/h) - about Mach 0.9 - on his descent. Baumgartner is expected to achieve a speed in excess of 690mph (1,110km/h) within about 40 seconds of leaving his capsule. With so little atmosphere at 120,000ft, he will drop very rapidly. Enhanced GPS (he actually carries four sat-nav systems on his body) will tell mission control just how fast he is moving. Baumgartner himself should hear tones in his helmet when he builds up to, and goes beyond, Mach 1.

Longest freefall time. Another of Kittinger's records that stands to fall. He plunged through the atmosphere for just over four-and-a-half minutes. Baumgartner hopes to better that by at least a minute. Altogether, from jumping out of the capsule to putting his feet on the ground, the Austrian should take around 10 minutes to complete the journey back to Earth. The landing in the desert is likely to be several tens of kilometres from the lift-off location at Roswell airport.

Highest manned balloon flight: The type of balloon being used for the flight would normally be deployed in unmanned scientific experiments. Some infrared and microwave telescopes, for example, have to get above the water vapour in the atmosphere or they can't see the cosmos. But no human has flown this kind of balloon (835,000 cu m/29.5 million cu ft) to the target height. Baumgartner can only claim an unofficial record in this category, however. The Federation Aeronautique Internationale, which certifies all aeronautic records, insists the pilot must be in the balloon when it returns to Earth for the mark to be endorsed. Obviously, that doesn't fit with the current project.

"We can talk about records here if you want, but I'm more concerned about the science we're doing," Joe Kittinger told me.

"Felix will be wearing the next generation of full-pressure suit; future American astronauts will be wearing this kind of suit. Felix will demonstrate that it works at 125,000ft."

There is no doubting that this is a dangerous endeavour. Two people who tried to better Kittinger's records in the 1960s lost their lives in the process.

Baumgartner has very sensibly built his project up step by step. He's jumped from 71,600ft (21.8km) and 97,100ft (29.6km) - each time he's learned something new, especially how to frame his body in the dive (he'll adopt a delta position, tracking head down).

There has been a lot of discussion about what is likely to happen if and when he goes supersonic. What impact will the shock wave have passing over his body? Could it knock him into a spin, or even knock him unconscious? In fact, the project director Art Thompson thinks very little will happen. He says the skydiver might not even notice when he has gone Mach 1.

"Because we're breaking Mach above any significant air density, the pressure wave should be pretty negligible. But he could see something more significant when he comes out, but again he's likely to come out at about 92,000ft," he said. "We're figuring he'll be in Mach for 20-22 seconds."

A lot has been made, too, of the dangers inherent in operating beyond the Armstrong line. Go above 63,000ft (19km) and exposed human tissue will begin to swell; bodily fluids like saliva in mouth and water in the eyes will start to boil. Hence the need for that full-pressure suit.

Baumgartner will also be on a pure oxygen supply. There is insufficient O2 to gulp where he is going, and if there is a breach in his visor the hypoxia will put him in a deadly place.

I must say, looking at this mission, it is actually the first few thousand feet of the ascent that will have me most anxious on the day.

Baumgartner has to achieve a certain altitude (3,000ft/1km) before he can rely on the emergency abort system in his capsule.

If his fragile balloon were to tear and suddenly deflate below this height, there would not be enough time for the capsule to release itself and deploy a parachute.

And there's certainly no chance of the Austrian jumping free himself, not when he has to negotiate a narrow doorway wearing a pressure suit - however next-gen and flexible it might be.

"We start breathing when we get above 3,000ft," says Art Thompson.

It is a response to the ever growing problem of orbital junk - old pieces of hardware that continue to circle the Earth and which now pose a collision threat to operational spacecraft.

The harpoon would be fired at the hapless satellite from close range.

A propulsion pack tethered to the projectile would then pull the junk downwards, to burn up in the atmosphere.

"Space has become a critical part of our infrastructure - from weather forecasting and Earth observation, to GPS and telecommunications," said the harpoon's designer, Dr Jaime Reed, from Astrium UK.

"Space junk poses a real threat to these vital services if we do nothing about it, and so it's very important we develop capture technologies to remove some of this material. Studies have shown that taking out just a few large items each year can help us get on top of the problem."

Dr Reed's proposal is for a barbed spear about 30cm in length. It would be mounted on a "chaser satellite" that would edge to within 100m of a junk object.

Pictures sent to the ground would then be used to assess the target, before the chaser was moved to within perhaps 20m to take a shot.

Once the harpoon is hooked through the skin of the rogue satellite or rocket stage, the chaser could either pull on a trailing polymer cord itself or deploy a separate thruster unit to do the job of dragging the aimless drifter towards Earth.

This is research in its very early stages. The BBC has filmed firing tests of a prototype harpoon at Astrium UK's Stevenage base.

The company, the largest space manufacturer in Europe, is also pursuing other ideas at its centres in France and Germany. These concepts involve nets and robotic grappling devices. All systems have their pros and cons.

Harpoons could deal well with a satellite that is tumbling, for example, but the approach has its critics because of the fear it could actually add to our problems in space.

"Historically, one of the great sources of debris has been the explosion of fuel tanks in spent rocket stages," explained Dr Reed.

"We obviously don't want to be the cause of that, so our harpoon has a crushable cylinder. It's like a piston, and as soon as the harpoon hits the satellite wall, it rapidly decelerates, ensuring we don't travel right through the spacecraft, puncturing the tanks."

More than 50 years of space activity have left a huge quantity of redundant hardware in orbit.

This includes not just whole satellites and the upper-stages of the rockets used to put them there, but also that debris from fuel tank explosions.

Today, it is said there are more than 22,000 objects actively being tracked.

These are just the big, easy-to-see items, however. Moving around unseen are an estimated 500,000 particles ranging in size between 1-10cm across, and perhaps tens of millions of other particles smaller than 1cm.

All of it is travelling at several kilometres per second - sufficient velocity for even the smallest fragment to do a lot of damage if it strikes an operational space mission.

Two events have really focussed the mind on this issue. The first was China's deliberate destruction of a decommissioned weather satellite using a missile in 2007. The second was the accidental collision in 2009 of the Cosmos 2251 and Iridium 33 satellites.

These two incidents produced hundreds of thousands of new fragments, negating all the mitigation gains that had been made over the previous decades.

Prof Richard Crowther is the UK Space Agency's chief engineer. He says there is a short window of opportunity to get on top of the issue before the number of collisions starts to increase and the problems associated with junk and debris begin to cascade. But he warns that any proposal for satellite removal requires international agreement because these systems could also be viewed as aggressive developments - as space weapons.

"If you've watched James Bond films over the years, you know that anything with a harpoon, with a laser, with a net in space has the potential to grab another spacecraft and destroy it," he told BBC News.

"So, we need to build reassurance within the space community and demonstrate that the systems being proposed are peaceful in their nature but also peaceful in the intent and the way in which they are going to be used."

The Astrium UK harpoon concept is being presented to the 63rd International Astronautical Congress in Naples on Wednesday.

There then requires just the money to run it for at least two years - the time it will take first to breach the current land speed record (763mph or 1,228km/h), and thereafter to raise it beyond 1,000mph.

The thinking is that once people see the Bloodhound SuperSonic Car (SSC) for real, the sponsors necessary to complete the job will make themselves available. That's the idea, anyway.

For as long as Bloodhound remains just a "paper vehicle" (or the dream of a computer animator), there will inevitably be some hesitancy, some doubts... which makes this week's first UK firing of the car's hybrid rocket engine all the more important. It's a very visible demonstration of progress.

"We've been very good at being a virtual car, if you like," says chief engineer Mark Chapman.

"We rely very heavily on computational methods, computational design, and we do some great imagery. And people go, 'well, when's that going to happen?'

"But we're now in manufacture. So perhaps the biggest statement to make is [that] this is the rocket test fire, but this is also the first stage of a column of dominoes that will fall over the next six to 12 months, meaning this time next year we will be in South Africa running the car."

To recap for those who haven't been following this project that closely, Bloodhound is essentially the same team that claimed the land speed record for Britain in 1997.

Then, RAF fighter pilot Andy Green became the first driver to break the sound barrier in a car called Thrust SSC at Black Rock Desert in the US. The project was headed by Richard Noble, with Ron Ayers acting as the chief aero engineer.

All three are back in this new effort which was launched as an education initiative to spur children's interest in Stem subjects (science, technology, engineering and mathematics). To date, more than 5,000 schools are using the example of Bloodhound and the science of fast cars to enliven their classroom studies.

Quite a number of these children will be on hand at Newquay Cornwall Airport's Aerohub this Wednesday to witness the live firing of Bloodhound's 18in by 12ft (45cm by 3.6m) hybrid motor.

Bloodhound will use three engines to go 1,000mph. Its main power plants are a Eurofighter-Typhoon engine and the hybrid rocket. But the vehicle also incorporates a Cosworth F1 V8 engine as well. Remarkably, its role is "merely" to push a liquid oxidiser into the rocket's fuel chamber.

It will achieve this by driving a high-performance pump, which is actually an updated version of a unit that was used on the UK's old nuclear cruise missiles.

Engineers have the complex task of getting the rocket, the F1-CA2010 engine, and its missile pump to all work in perfect unison.

The Newquay test will be the first time the Bloodhound team has seen the trio and their control system run in anger. It's R&D in public.

Testing will be conducted inside a concrete-hardened hangar used in the past to house Tornado fighter-bombers.

The shelter was built to withstand attack by enemy bombers so if anything should go awry, the watching public - huddled in another Tornado shelter - should be perfectly safe.

Britain was very much at the forefront of rocket development during the post-war years.

The biggest system ever tested in the UK was the Blue Streak ICBM. This was done on a static test stand in Cumbria in the early 1970s (300,000lbf; 1,300kN).

More recently, in the 1980s, the Stonechat motors for the Falstaff research rocket were fired at Wescott in Buckinghamshire (60,000lbf; 270kN).

The Bloodhound hybrid is probably the most impressive since then.

"This rocket's designed to produce an average thrust of 25,000lbf, or 111kN, for 20 seconds; and that's what's required in conjunction with the jet engine to get Bloodhound to that 1,000mph," Daniel Jubb, the brains behind the power unit, told me.

"It actually needs to produce a peak thrust of 27,500lbf (122kN), and that peak thrust needs to be right at the end of the burn when the aerodynamic forces on the car, the drag, are at their highest.

"We're actually running at just over half-full chamber pressure on Wednesday, so because the nozzle is optimised for the full thrust firing, we're not going to see massively high levels of thrust, but we then have a series of development firings from later this year through to early spring in which we'll progressively increase the chamber pressure until we get the full performance."

In Wednesday's test, liquid oxidiser (high-test peroxide, or HTP) will be fed into the chamber at a pressure of 600psi (4MPa) to react with the solid fuel (hydroxyl-terminated polybutadiene, or HTPB). This should deliver an average thrust of 12,000-14,000lbf (50-60kN) with a peak somewhat over that. The burn will last 10 seconds.

Assuming all goes well, subsequent firings will eventually take the rocket up to its full performance.

As Daniel Jubb explained, a further four "R&D" burns should then prove the technical requirements of the rocket. There will also be an additional 10 "safety and acceptance" firings that will explore some of the rocket's limits, to certify the system for use in a manned vehicle.

All these firings are expected to take place in Newquay. Indeed, when the car does its first roll tests, it is likely to use the Aerohub runway, which means the Cornwall town is going to be an interesting place over the coming year.

It turns out that the full performance of the rocket is not needed to break the land speed record. The team plans to run it in a monopropellant mode only next year. In this configuration, the HTP is passed over a catalyst pack to decompose it into steam and oxygen, but instead of igniting a fuel grain, this superhot gas is allowed simply to vent through the chamber nozzle. This alone should produce 10,000lbf (45kN) of thrust, sufficient with the Eurofighter jet (20,000lbf/90kN) to take Bloodhound through the sound barrier to about 850mph.

All this has me wondering, though. What would happen if you pointed the car towards the sky. How high could it get?

"We've worked that out with some children in a school project," says Mark Chapman. "They were doing Newton's laws, F=ma. That kind of thing. With the full fuel burn onboard, Bloodhound got to 25,000ft and broke the sound barrier at about 17,000ft. It was a kid that asked that question. How high will it go? Fantastic."

Although, we should stress that a huge amount of design effort has gone into making sure this vehicle stays flat on the ground.

Classic meteors - fragments of rock - tend to flash across the sky in an instant.

An incoming satellite on the other hand, can take longer to blaze overhead, giving many more people the chance to notice it.

There is now a wild jungle of redundant hardware up there - everything from old rocket stages that continue to loop around the Earth decades after they were launched, to flecks of paint that have lifted off once shiny space vehicles and floated off into the distance.

Gravity demands it all comes back to Earth at some point.

The bigger the returning object, the bigger the light show.

Space debris: Time to clean up the sky

Because of the billions it costs to develop these special space systems, they're purchased in batches. The satellites then sit in storage until they're needed.

It means that newly launched spacecraft can in fact contain equipment which was delivered from the manufacturer years earlier.

This is the case with Europe's latest meteorological platform - Metop-B. It is the second in a three-satellite series and has just gone into orbit on a Soyuz rocket.

The first satellite, Metop-A, was launched back in 2006. The third platform, Metop-C, probably won't go up until about 2018. But all three of these spacecraft are circa early 2000s, and the industrial contracts that brought them into being were circa early 1990s.

So you have to wonder - how can anything that "old" deliver any sort of service that can be described as "new"?

It was a puzzle on my mind when I went to see one of the main British contributions to the Metop programme.

This is the Microwave Humidity Sounder (MHS), one of the eight meteorological instruments carried on each of the three identical Metop satellites.

UK engineers built these washing machine-sized objects to measure the water content sitting at different altitudes, including atmospheric ice, cloud cover and precipitation (rain, snow, hail and sleet).

It is fundamental information needed by the computer models to produce our daily forecasts.

The MHS batch model I saw will go up on that final 2018 Metop-C, a full 17 years after the instrument came off the "production line".

When you lay eyes on this remaining sounder, you immediately recognise its age. A little plate screwed to the side of the instrument announces the name of the manufacturer - Matra-Marconi Space. It is a famous name that no longer exists, subsumed years ago into the pan-European aerospace giant Astrium.

But, insists project manager Ian Stewart, "MHS was state of the art in '93, and it's state of the art today".

He keeps an eye on things. Every year, he pulls the model out of its storage container to check everything is in good working order. If anything is playing up, it can be exchanged easily.

"We've built a lot of pre-assembled units in there. It's not quite plug and play, but it's as good as that. We don't have to go and de-wire boards - we have a replacement unit that we can just slot in."

But even if the hardware looks a bit quaint by today's standards, what about the science it can do? It's tip-top, maintains the UK Met Office; and like all the Metop instruments, MHS continues to stretch the models and the forecasters

"We're still in the situation where the data from this instrument is the topic of research," explains Nigel Atkinson, an expert scientist in satellite applications at the Met Office.

"Some of the data from the standard humidity channels, we know how to handle; and then there's the precipitation-affected channels that are a new area. So, we can exploit this data and improve weather models. We're not sitting there saying 'this is an obsolete instrument' - it is still something which can push forecasts forward."

In other words, the data MHS acquires is made to work harder and harder as the science of meteorology advances.

Studies have compared all the different types of observations (including surface weather stations, balloons and aeroplanes, etc) ingested in weather models and found that Metop data makes the largest contribution to the accuracy of 24-hour lookahead, at around 25%.

Is is a big impact. Consider for a moment all the lives that have been saved and all the damage to property that has been prevented by Metop-supported weather forecasts. The value of those forecasts must equate to hundreds of millions of pounds every year across Europe.

Inevitably, though, the time comes when one must move to next-generation instruments. That is the discussion taking place right now, although the cost of a new and improved Metop system means the future satellites and their instruments will again be a batch-buy. The figure being quoted is just shy of 3bn euros for a series of spacecraft that would likely operate in the 2020s and 2030s.

The cost will fall on nations that are member states of the European Organisation for the Exploitation of Meteorological Satellites (Eumetsat), which operates Metop; and the European Space Agency (Esa), which leads weather satellite R&D in Europe.

British industry is keen to play its part and has put a case to government, through the UK Space Agency, to be allowed to develop the MHS follow-on instrument.

This will be known as MWS (MicroWave Sounder). It will do broadly the same as MHS but better (25 channels versus five channels).

It will also incorporate the observations of another current Metop instrument, Amsu (Advanced Microwave Sounding Units A1 and A2), which makes temperature profiles of the atmosphere.

"MHS is proven; it's a critical part of the forecast system. If we don't receive the data for some reason, the forecast degrades," says Brett Candy, a data assimilation scientist at the Met Office.

"For the future, we'd be looking for improved accuracy in the observations, hopefully improved resolution, perhaps more channels looking at different layers in the atmosphere - but really a continuation of the great instrument we've already got.".

And for Astrium, which now curates the Matra Marconi heritage, Mike Healy observed: "Sometimes, you put together a satellite instrument and there isn't a possibility of a follow-on.

"The nice thing here is that we have that possibility. The basis and all the lessons learned that were made for MHS - we can put that now into MWS, provided the UK subscription is big enough. This is about jobs and hi-tech manufacturing, so it should fit with the government's desire for growth," the director of the company's Portsmouth base said.

The manoeuvre will put the probe on a path to flyby Earth in October next year. This sweep around the home planet will then give the mission a gravitational boost and the velocity required to get it out to Jupiter in July 2016.

What you might not know is that this critical event depends on British-designed and -built hardware.

Juno is equipped with a Leros-1b apogee engine prepared by Moog-ISP of Westcott.

Westcott has a rich history. It was at the old Buckinghamshire RAF base after WWII where the government established its guided weapons programme, producing solid motors and liquid engines.

Today, this quiet corner of England is developing propulsion systems for important spacecraft like Juno.

The Jupiter probe's Leros-1b was originally designed to put telecommunications satellites in the right part of the sky.

When these platforms are dropped off by their launch rockets they are in a large ellipse around the Earth running from just a few hundred km above the planet out to 36,000km.

An apogee engine makes a series of burns at the top of the ellipse to circularise that orbit and bring the satellite into a "stationary" parking position where it can then relay its TV pictures, phone traffic, broadband, etc to a particular region, 24/7.

The major American manufacturer Lockheed Martin was the first to use the high thrusting (635 newtons) Leros-1b on its telecoms platforms, but the engine has also found favour at the US space agency down the years.

The Mars Global Surveyor, which mapped the Red Planet from the late 90s, and the Near-Shoemaker probe, which visited an Asteroid Eros in 2003, both carried the Westcott technology.

Of those Nasa missions in action today, the Messenger venture at Mercury has a special reason to thank its Leros hardware.

"Messenger was particularly nice for us because it was the first time that any artificial satellite had gone into Mercury orbit," explained Dr Ian Coxhill, the chief engineer at Moog-ISP

"It was a proud day for us to know that our engine actually did the insertion burn to drop the spacecraft into the correct orbit.

"The engine braked the orbital speed. It was a delta-v opposite to the direction of travel and that slowed Messenger enough so the relatively weak gravity of Mercury could capture the spacecraft and put it into an elliptical orbit around the planet rather than the Sun."

The Leros-1b on Juno will be required to do something similar in July 2016 when the mission arrives at Jupiter. But first it must put the probe on the right path to the Gas Giant.

Juno was launched in August last. It has since travelled some 480 million km from Earth, beyond the orbit of Mars.

Two 30-minute burns of the hydrazine-fuelled Westcott engine - the first was conducted last Friday - will bring the spacecraft back towards the home planet for a classic gravitational slingshot out to Jupiter.

"We're pretty much hands off at this stage," Dr Coxhill says.

"Nasa's mission control is running things. If they see something they don't like - such as temperature readings that are too high - they might give us a call.

"We always like to get some feedback, which is not always possible because of security restrictions, and we understand that. But we put blood, sweat and tears into making our engines and just hearing there was a 'nominal burn' gives us a warm feeling."

Moog-ISP now produces a 1c derivative of the Leros as well. This is trimmed for slightly less thrust (450N). It was fitted to the Boeing-built Intelsat-21 and -22 telecommunications spacecraft that were launched in August and March of this year.

You will see the 1c on the next generation of the US DoD's Global Positioning System (GPS) satellites, also - GPS-III.

"We're an export business. We're a UK company that makes most of our money selling into the US," emphasises Dr Coxhill.