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Archives for December 2010

Mars Rover: Creaking, arthritic... but still rolling

Jonathan Amos | 17:27 UK time, Thursday, 30 December 2010

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"This is kinda like the senior marathon runner who after a long run will ice up their knees and take some ibuprofen to get them ready for the next long run."

That's how the project manager on Nasa’s Mars rovers John Callas describes the Opportunity vehicle.

Opportunity's drive across Mars

Distant target: The rim of Endeavour Crater is seen in the bottom-right of the image

Amazingly, this six-wheeled robot is about to celebrate its seventh anniversary on the Red Planet.

It's now covered more than 26km since its arrival on 25 January, 2004.

And remember, this was a mission [1.43 Mb PDF] that had the initial goal of surviving only three months on the surface.

Opportunity is well and truly "out of warranty", but it continues to roll - albeit backwards.

Engineers decided that putting the robot in reverse would help prolong its gearboxes by allowing their teeth to wear on the opposite side.

Opportunity's robot arm - the device it uses to reach out to interesting rocks - is increasingly "arthritic".

One of its joints no longer works properly and so, like an elderly human, the rover has to swivel its whole body sometimes to get the arm into just the right position.

Some of Opportunity's instruments, too, are worn and prone to anomalies. But the software equivalent of ibuprofen certainly seems to do the trick because this rover is on the cusp of what could yet be its most exciting days.

Within the past month, the rover has arrived at a crater on the Meridiani Plains that has been dubbed Santa Maria.

Opportunity was directed to this 90m-wide bowl because the Mars Reconnaissance Orbiter (MRO) circling overhead had seen some interesting rock outcrops.

Santa Maria

Santa Maria should reveal more information about the period when Mars was getting drier and drier

It's difficult for the satellite to make definitive identifications of minerals on the ground because martian rocks weather over time and acquire a dust layer that hides many of the details of their true nature from the "spy in the sky".

Santa Maria would appear to be different, however. It's a fresh crater; it was dug out in the recent geological past and so MRO has been able to get a good look at the prospective mineralogy.

The crater has a strong signal for a particular type of magnesium sulphate (kieserite) which is likely to help Opportunity fill in the story it has been developing these past six years.

This story, written in the rocks of all the craters visited by the rover, tells us of a Mars that was probably losing its atmosphere about 3.8-4.0 billion years ago - a planet where acidic surface waters were in retreat. Ray Arvidson is the rover's deputy principal investigator. He told me:  

"These craters are Nature’s drills to expose the bedrock. What we've seen throughout the history of this mission is continuing evidence that our original hypothesis is correct - that these are layered sedimentary rocks during what appears to be a drying-out period on Mars where occasionally there would be wet playas or lakes that would form mud, would dry out, the wind would blow, make sandstones, they'd accumulate, and then the ground water would come up and cement everything."

In other words, Opportunity is giving us a window on to the time when Mars was in the process of turning into the cold, dusty, desolate world we recognise today.

Mars rover

The rovers were designed for a three-month mission

But Santa Maria is just for starters. Six kilometres as the crow flies in a south-easterly direction is the 22km-diamter Endeavour Crater.

The impact which made this bowl has exposed even older rocks. These show evidence from orbit of clay minerals that were likely formed 4-4.5bn years ago in long-standing, neutral water.

This would be a window on to Mars' wetter, warmer past, a time when microbial life could perhaps have found conditions to its liking.

The clay mineral deposits look to be pretty big, covering a peak on the crater rim called Cape Tribulation.  The peak is just visible to Opportunity when it looks to the horizon.

Will the rover make it to Endeavour after studying Santa Maria; will its systems hold out on the great drive?

Well, the signs are encouraging.

Santa Maria

Santa Maria viewed from orbit: It was dug out in the geologically recent past

The "senior marathon runner" has managed more than 12km in just the past Martian year.

Nothing is for certain, of course, and you’ll notice I've made no mention in this post so far of Spirit, the other Nasa rover on Mars. Its seventh anniversary actually comes up before Opportunity, on 4 January.

Spirit is stuck fast in a sand trap, and has been in winter hibernation since March.

Sited at a higher latitude in the Martian Southern Hemisphere than is Opportunity, it doesn't currently receive enough sunlight to power its solar cells and communicate with Earth.

Callas and his team of engineers have long since given up hope of ever driving Spirit again, but they do want to revive the machine - if only to act as a static weather station. Callas told me:

"Spirit is located further south than Opportunity is, and so its winters are a lot deeper and tougher. We've always had to position the rover by tilting it so that the solar arrays point towards the north. We weren't able to do that so the rover didn't have enough energy to stay awake in the winter time and so it’s gone into a deep sleep. Our models estimated that at some point in the springtime the rover would power back up.

"The concern though is that the rover should have seen colder temperatures than it had ever seen on Mars, and that it would get below the nominal cold operating temperature for the electronics.

"There's a risk that the rover wouldn't survive the winter. We're listening now; we're listening every day to see if the rover would autonomously wake up and talk to us. We've also been actively commanding to the rover in case it’s in a potential alternative fault mode. But the period of peak solar energy production is going to be around the mid-March timeframe.

"If we have not heard from Spirit by then the likelihood of hearing beyond that starts to decrease."

Fingers crossed.

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Searching for the 'new Oklahoma' in space

Jonathan Amos | 22:00 UK time, Friday, 24 December 2010

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If you were drawing up a list of the buzz space phrases of 2010 then the term "Ka-band" would surely feature.

I've certainly spent a good part of the year talking and writing about this particular portion of the radio spectrum.

We've seen a number of fascinating developments in telecommunications that will operate in Ka, a much higher frequency than is generally the staple of satcoms. Among the topics:

Hylas-1 – the first net-dedicated satellite working in Ka that was launched to fill the broadband "not-spots" of Europe.

Inmarsat – the world’s biggest Mobile Satellite Services company that ordered three Ka spacecraft to cement its current business whilst trying to move it into new areas as well.

O3b – an utterly intriguing, Google-backed project to provide "fibre in the sky" to support internet connections in the developing world. This will take the form of a constellation of low-orbiting spacecraft, again operating in Ka.

And then there is the appropriately named Ka-Sat which will be operated by Eutelsat, one of the world's big three Fixed Satellite Services companies. This six-tonne spacecraft is going into orbit on the year's final commercial Proton rocket launch from Baikonur.

Ka-Sat being tested (EADS Astrium)

Ka-Sat is a new venture for Eutelsat which is best known for delivering thousands of TV channels 

 

Eutelsat is more accustomed to streaming thousands of TV channels across its fleet of geostationary spacecraft, but it has chosen to make a big play in the market for satellite-delivered broadband and has resorted to the high frequencies of Ka to make it happen.

So what is the buzz of Ka all about? A question I put to Eutelsat's CEO Michel de Rosen:

"Our business is to manage signals that go up and come down, and these signals use frequencies.
"There are frequency bands of different nature. For industrial companies that started working in this field 30 years ago, the easiest band to work in was the lowest band – the C-band. And then operators started moving into a higher band called Ku-band. Ka-band is higher still. And the reason Ka-band was not worked in previously is that it presented some technological challenges that were not handled well 20 years ago, but which have now been absolutely mastered.
"The situation is that C-band and Ku-band are becoming crowded. We have to think long term in our industry because a satellite takes three years to build and works for 15 years. And at Eutelsat, we had to think where our growth would come from in the future – where was our 'new Oklahoma', our new territory? And the clear thinking at Eutelsat is that Ka-band is the territory we’re going to have to work with more and more."

Ka's time has come, then; and part of the picture is our insatiable desire to use the internet wherever we are, from the mountaintop to the middle of the ocean.

If you are going to use a satellite to provide such connectivity then Ka gives you the "wide pipe" you need.

Eutelsat says Ka-Sat will be the most powerful civil telecommunications satellite ever sent into orbit. It will have a total throughput of some 70Gbps. This will be channelled via 82 spot beams on to different market areas stretching from North Africa to southern Scandinavia. A very small segment of the Middle East will also be reached.

Consumers will be offered broadband packages generally up 10Mbps, with some specialist markets able to buy up to 30Mbps.

Of course, most of Ka-Sat's users will not be in exotic places. Rather, they will be at home in Europe, somewhere where current terrestrial technologies – fibre, ADSL, 3G, 4G, etc – do not reach.

It's the same underserved market that Avanti's Hylas-1 spacecraft is also targeting.

There's a lively debate right now about just how big this market is today and how it will evolve in the years to come.

There are probably tens of millions of households across Europe which still cannot get a decent net connection. But governments and telecom companies have promised to close the not-spots.

In the UK, the new coalition government recently re-stated the universal broadband commitment on a minimum 2Mbps connection for everyone, although it has let the target date for achieving this commitment slip.

From the satellite operators' perspective, this is an important issue because the pace and scope of the roll-out of better terrestrial technologies, and of fibre in particular, may determine the profitability of their Ka ventures.

It's recognised that the relative speed, cost and surfing experience offered by satellite will never be a match for fibre. And if more people are offered the fibre solution, fewer will need to resort to the satellite option.

Eutelsat says it has weighed this issue carefully and has come to the conclusion that there will be a rump – and a sizeable one at that – of European households for which satellite may be the only chance of getting a decent internet connection for many years to come. Michel de Rosen:

"Some observers have said, 'hey, Eutelsat! Are you sure about Ka-Sat? You’re investing 250m euros'. It’s a significant investment. People ask us if this venture is really going to be profitable. We do believe it, and all the studies we do and all the discussions we have with our distributors tell us that the need is there and we expect that this need will grow.
"We’re not launching 10 Ka-Sats; we’re launching one. Our satellite to be totally saturated has a nominal capacity up to two million households. And this is the maximum, and it assumes the satellite provides only the broadband service and no others. That won't be the case. It will be able to deliver other services as well like professional video and data services for corporations.
"So let's say for instance that Ka-Sat will serve only one million broadband households and do some of these other services. Well, if we assume today that there are 30 million households that do not get good broadband services, and even assuming that Avanti's Hylas satellite serves some of these people - we only need about 3% of the 30 million to saturate Ka-Sat."

A couple of quick notes to finish on. The first: whenever I talk about satellite broadband someone will usually make a comment about latency, the delay in signal travel time up into space and back and the grief this introduces into the internet experience.

It exists, it's true; although technical tricks have improved matters considerably. But for those people who currently have to put up with ultra-slow, low-latency connections and who do not look like they will get a fibre solution anytime soon, a high-speed, high-latency option provided by satellite will almost certainly be preferable, surely?

Second: we began the year talking about a new climate of optimism in British space and the opportunities that existed for the UK to grow its space industry. Ka and broadband-by-satellite are evidence of that.

Both Ka-Sat and Hylas were "made in Britain". Indeed, a year ago I stood in the EADS Astrium cleanroom in Portsmouth with the communications payloads of both spacecraft no more than a couple of metres away from me on either side.

 

The Dragon capsule creates quite a splash

Jonathan Amos | 02:01 UK time, Thursday, 9 December 2010

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"It's just mind-blowingly awesome. I apologize, and I wish I was more articulate, but it's hard to be articulate when your mind's blown - but in a very good way."

The capsule hit the water three hours, 19 minutes and 52 seconds after the launch from Florida

The internet and space entrepreneur Elon Musk must have the biggest grin in the world right now, and who could blame him.

Not only has he seen his big rocket, the Falcon 9, work straight out of the box and complete two successful launches, but his space capsule, Dragon, has also now made an impressive debut.

After all the brickbats he's had thrown in his direction from the naysayers on Capitol Hill in recent months, it must be the sweetest feeling. Wednesday's first demonstration of Dragon appeared to go like a dream.

Musk's company, SpaceX, launched the spacecraft from Florida into low-Earth orbit atop the Falcon at 1043 EST (1543 GMT).  

The capsule separated as expected at an altitude of 300km and then circled the Earth at speeds greater than 27,000km/h, before executing a re-entry.

A heatshield protected Dragon in the fiery phase of the descent.

Drogue chutes then opened on cue to slow the fall still further, followed by the deployment of the main chutes.

The splashdown occurred in the Pacific, west of Mexico a little after 1400 EST (1900). Early data suggests the capsule came down within about 800m of the notional pin-point target.

A view from inside Dragon during the flight.  Will astronauts soon see this?

A view out of the window of Dragon during the flight

A boat picked the capsule out of the water.

This is the first time a privately developed spacecraft has been recovered safely on its return from low-Earth orbit. It is a feat achieved previously only by big government agencies.

There's a long way to go, of course. In the space business, early success is no guarantee of future performance. But so far, so good. Falcon and Dragon have been developed with help from Nasa's Commercial Orbital Transportation Services (Cots) programme.

The initiative marks a new way of doing business for the agency. Instead of Nasa setting requirements and then engaging a contractor to deliver them, Cots defines capabilities and then leaves it up to the company to work out how they should be delivered.

Incentive payments are earned with every milestone passed. Before Wednesday's launch, SpaceX had completed 17 milestones and had received $253m.

 

Nasa believes this type of approach will lead to cheaper means of getting cargo to the space station in first instance, and then, eventually, astronauts as well.

SpaceX says it has spent just over $600m in getting to this point.

By any standard, that is considerably less than traditional, government-led programmes have cost to produce the same ends.

No-one can say for sure how this venture will eventually turn out, but the success achieved so far has got to make "old space" sit up and take notice of what "new space" is doing.

In previous blogs, I've spoken about the barrier that the high cost of launching rockets is to space activity.

Lower the cost and it becomes possible to do so much more. Elon Musk and SpaceX may just have taken a giant leap in that direction on Wednesday.

Bretton Alexander - the president of the Commercial Spaceflight Federation, a coalition of companies banking on this bright new future - lauded the achievement of SpaceX:

"It's a milestone on the path to realising the first commercial human spaceflight capability. It's historic in that it's the beginning of a paradigm shift from a government human spaceflight architecture to one that opens up human spaceflight to the private sector."

The capsule was recovered and will now undergo a detailed examination

Elon Musk's next objective now is to go to the space station next year with Dragon to deliver supplies. Ultimately, though, he wants Nasa to green-light the process of turning his capsule into a fully fledged crewship.

It was designed with that purpose in mind and Musk says the capability could be made available within three years of getting a contract to do it.

"People sometimes think that to take a cargo spacecraft and put crew in it requires this enormous amount of magical pixie dust. This is not at all the case. If there had been people sitting in the Dragon capsule today they would have had a very nice ride. They would have experienced up to 4.5Gs - about what you would see in an amusement park. Except for the escape system, its seats and some minor upgrades to the life support system - the vehicle you saw today could easily transport people."

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Landing on Mars in 2016

Jonathan Amos | 10:59 UK time, Friday, 3 December 2010

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I remember going up to a leading French planetary scientist at a meeting in Paris last year and asking if he was interested in taking part in Europe's mission to land a spacecraft on Mars in October 2016. "No," was his response, "because there is no science on it."

The landing platform will be carried to Mars inside its conical entry shell.  The structure will be attached to the side of an orbiter that will study atmospheric gases

The landing platform will be carried to Mars inside its conical entry shell. The structure will be attached to an orbiter that will study atmospheric gases

There is... just not very much, and it will be very short-lived; this post will attempt to explain why.

Europe's plans for Martian exploration (called ExoMars) have been revised, reviewed and re-scoped so much down the years that you could be forgiven for not having the foggiest idea what's going to happen.

But the plans are now set. Industry submitted the Preliminary Design Review documents to the European Space Agency (Esa) at the end of October, and full implementation is expected to start in April next year.

It's now all a joint affair with the Americans. Europe will build an orbiter and lander for 2016, and then in 2018 both Europe and the US will be sending rovers to the Red Planet. There should be follow-on missions too in 2020 and 2022.

This week, Esa released an Announcement of Opportunity on that 2016 lander. It's basically a call to the research community to come forward with ideas on how to use the lander for science. And, as I said, the resources available will be minimal.

The lander is, first and foremost, a technology demonstration that will prove Europe's ability to get down on to the surface safely. Everything else is considered secondary, including the science.

Europe has not yet landed on Mars. Its one previous attempt - the UK-led Beagle-2 spacecraft - did not call home after making its bid to get to the surface. The intention of the new attempt is to develop a system that can be scaled up for future missions when science will be the priority.

The size of the entire 2016 module is 600kg - that's everything needed to enter the Martian atmosphere, survive the fiery descent, and then make a controlled landing.

A doppler radar will judge the distance and speed to the ground; thrusters will pulse on and off to bring the craft to a halt

A doppler radar will judge the speed and distance to the ground

I've put some pictures in this post which illustrate what the lander will look like and how it will get down.

As always, it's a perilous journey to the surface of Mars.

The capsule will hit the top of the Martian atmosphere at 5.7km/s

The surface platform must shed its protective shell after the fiery phase of the entry

An entry capsule with the surface lander inside will be spun off the orbiter a few days before arrival at the Red Planet.

The 2.4m-wide, conical, protective shell will hit the top of the Martian atmosphere at about 5.7km/s (13,000mph).

Pushing hard against the Martian air, its descent will begin to slow. The module's front shield will also get very hot.

A parachute will then be deployed to reduce the rate of fall still further. Finally, the surface platform will detach from the chute and pulse its thrusters.

With speed and distance information coming from a doppler radar, the platform should bring its velocity down to zero about a metre above the ground.

The lander has no legs, so it simply dumps down. A crushable material on the underside of the platform should prevent any damage from rocks that might be lying right on the point of contact.

The entire landed mass should be about 300kg.

One of the great unknowns in all this will be the Martian weather, and engineers are preparing for very unfavourable conditions. Vincenzo Giorgio is leading the industrial side of the ExoMars project at prime contractor Thales Alenia Space (Italy). He told me:

"Because of the hyperbolic insertion we cannot control when we are going to land on Mars, and unfortunately we will be in the middle of the dust storm season. That's the worst scenario in which to try to land on the planet. Therefore we have to design for very strong horizontal winds."

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The surface platform will not carry solar panels or a radioisotope power source. It will have a battery and that's it. This will give the science sensors built into the platform at least four days, perhaps eight, to gather their data before dying.

The orbiter should pass overhead a couple of times while the battery is still alive, allowing the data to be up-linked and relayed back to Earth. But what sort of data?

The mass available on the platform for science instrumentation will be just three kilograms. This instrumentation will comprise environmental sensors. They'll be gathering information about pressure, the amount of dust in the atmosphere, perhaps ultraviolet conditions, and the like. It's all to be decided. That's the point of an AO. Scientists bid for what they'd like to do.

There may or may not be a camera. It's possible no researcher in Europe will propose one. I doubt that somehow. Can we really send a probe all the way to the surface of Mars and not have a photo? Dr Jorge Vago is the ExoMars project scientist at Esa. He told me:

"The objective is geared towards technology demonstration. We are trying to make a little bit of room for some science on a spacecraft that is really, really full of systems that are required for landing. This is not the type of landing system you would use to land, let's say, a Beagle-2 type of spacecraft. It is really aiming to demonstrate a large system without the payload, more or less.
 
"This will be the first mission in very long time that is landing in the middle of the statistical dust storm season, and the lander will be designed to cope with that. All other missions avoid this time of the year like the plague. And as such it will be a unique opportunity for characterising the entry, descent and landing atmosphere.
 
"One of the things we hope to do is measure pressure because there are some discrepancies between the results of Viking and Pathfinder that are driving the modellers crazy, and they are crying out for a new measurement to try to settle the issue. And in times of high dust content, there may be electro-static discharges in the atmosphere we could look for.
 
"There are many measurements that could be made in a few days and that would be very useful. Of course, it will not be the same level of science return that you might get from an environment observatory that stays on the surface for a full Martian year. Nevertheless we think we can get useful results."

You can live the dive to Mars' surface by listening to Maurizio Capuano. He is the entry, descent and landing demonstrator model programme manager at Thales Alenia Space.

I asked him to describe the whole sequence from the moment the capsule comes off the orbiter. Click on the box below and you'll get an idea of the complexity of the endeavour.

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