Video tracks stricken Mars probe


Thierry Legault's video of the Phobos-Grunt probe

The failed Russian Mars probe Phobos-Grunt has been pictured moving across the sky by the Paris-based amateur astronomer Thierry Legault.

The spacecraft is seen moving left to right in the video. The bulbous shape of its fuel tanks and its outstretched solar panels are easily discernable.

Mr Legault uses a sophisticated telescopic tracking system and captured similar imagery of Nasa's defunct UARS satellite last year.

Phobos-Grunt is falling to Earth.

It is expected to re-enter the atmosphere in the next 8-9 days and burn up.

The Russian space agency (Roscosmos) said on Friday that perhaps 20-30 pieces weighing no more than 200kg in total might survive the destructive dive and impact the surface somewhere.

Asked how easy it was to grab the shots with his telescopic system, Thierry told BBC News the, "difficulty was very comparable to UARS; they had comparable speed, brightness and size. Except that I had to drive more than 800km to find clear skies in the French Riviera!"

Thierry Legault Thierry with his equipment at the Calern Plateau Observatory above Nice

The engineer has posted the video and how he went about acquiring it on his Astrophotography website.

On Friday, Phobos-Grunt was moving around the Earth at an altitude that varied between 177km (perigee) and 224km (apogee). But this orbit will rapidly decay over the coming week as the spacecraft drags through the top of the atmosphere.

As it encounters more and more air, so its descent will accelerate.

The spacecraft's mass at launch was just over 13 tonnes, but some 10 tonnes of this was the fuel it expected to use in the course of its mission to the Red Planet's largest moon.

The propellants, unsymmetrical dimethylhydrazine (UDMH) and dinitrogen tetroxide (DTO), are highly toxic but they will almost certainly be consumed in the fireball that engulfs Phobos-Grunt when it makes its death dive to Earth.

Part of the confidence on this matter stems from the construction of the fuel tanks.

"The Russian space agency reports they are largely made of aluminium, which has a very low melting temperature, compared to the titanium tanks that can survive re-entry and can sometimes be found on the ground," explained Dr Holger Krag from the European Space Agency's Operations Centre (Esoc) in Darmstadt, Germany.

"We can expect the tanks to break up and release their contents. There will be a self-ignition of the UDMH and if it does not all burn up, it will be so dispersed there will not be a critical concentration."

Dr Krag and colleagues at Esoc, like a number of teams around the world, are now busy modelling the decay in Phobo-Grunt's orbit.

Esa is a member of the Inter-Agency Space Debris Coordination Committee (IADC), a forum for the worldwide coordination of activities related to the issues of man-made and natural debris in space.

The other teams working through the IADC will all be using slightly different assumptions in their models and, as a consequence, will all arrive at slightly different timings for the period of impact. A host of amateur groups will be engaged in a similar endeavour.

The hope is that by comparing the different pre-fall projections with the observed re-entry data after the event, future modelling efforts can be finessed.


At the moment, the projections are very uncertain. They are clustering around Sunday 15 January (GMT) and Monday 16.

Much of the uncertainty is related to the state of the atmosphere. During phases of higher solar activity, the atmosphere becomes excited and more extensive, pulling spacecraft and other pieces of debris in towards the Earth much faster than during phases of low solar activity.

Right now, the Sun is moving towards what is expected to be solar maximum - its most active state - over the next year or so, meaning that we are entering "harvest time" for space junk.

But precisely where Phobos-Grunt will re-enter in the coming days is really anyone's guess at the moment.

Phobos-Grunt - Mishap sequence

  • 8 Nov (GMT): The probe launched successfully on its Zenit rocket from the Baikonur Cosmodrome
  • It was dropped off 11 minutes later in an elliptical orbit some 345km above the Earth
  • Two firings from the probe's hydrazine-fuelled cruise stage were planned over South America
  • The first, lasting 11.5 minutes, should have raised the orbit of Phobos-Grunt to 4,000km
  • A second burn, four hours into the mission, was to have sent the probe on a path to Mars
  • But Russian engineers later confirmed that neither burn took place
  • Controllers have had only limited radio contact with the probe; mission recovery was not possible
  • Re-entry is now expected in mid-January; 20-30 fragments are expected to survive the descent

The maximum latitudes seen by its orbit are 51.4 degrees North and South. This encompasses London (UK) in the Northern Hemisphere and Punta Arenas (Chile) in the Southern Hemisphere.

"But remember, the prediction uncertainties currently are on the order of one or two or even three days and Phobos-Grunt is making one full revolution of the Earth every 90 minutes - about 16 orbits a day. So, it's just not possible to identify a particular region at the moment," Dr Krag told BBC News.

What would help would be a wider ground network of radar sensors to scan the sky.

The more frequently a spacecraft's orbit is sampled, the better the projections would get, particularly towards those final hours before impact.

Esa is building up its Space Situational Awareness programme, and the other agencies involved in the IADC are doing likewise.

"If we ever got the system we dream of, with a really good, globally distributed system of sensors, then we might be able to do a last prediction one or two hours before the actual re-entry," Dr Krag speculated.

"You might be able to nail it down to regions, oceans or continents - perhaps selected countries, but not any further in my view."

If Phobos-Grunt comes back in over a part of the world that is in darkness, it should produce a plasma trail that is visible to anyone watching from land or on a ship.

Europe saw a spectacular example of this on the night of 24 December when a Soyuz rocket stage fell to Earth.

Jonathan Amos Article written by Jonathan Amos Jonathan Amos Science correspondent

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  • rate this

    Comment number 38.

    Perhaps the safest route into space we can achieve with today's technology base is using nuclear rockets. Safety margins are/can also be improved by using on-board human crews because they can do ad-hoc repairs.

    For a manned Mars mission the safety factor using nuclear could be as much as ten times higher than using chemical only rocket tech. - Though of course nuclear has its own small problems.

  • rate this

    Comment number 37.

    #35 ColadadelCid et al
    We don't really have 100% safety even with air or sea travel. Even going into orbit is genuinely dangerous by any modern measure. It is incredibly difficult to make space technology safe and reliable. The criticality of going into space means that it never will be totally reliable with current technology. Looking into the immediate future...

  • rate this

    Comment number 36.

    There is no Mars curse, it is just that going to Mars is much more difficult than putting things in orbit. Russia has a terrible record with planetary probes compared with NASA because its technology, especially its computing and control, is much more basic. Getting out of Earth Orbit to Mars is not too difficult, landing is much harder. A landing by NASA's MSL would be a fantastic achievement.

  • rate this

    Comment number 35.

    The best laid plans of mice and men often crash to earth. This despite hundreds of engineers and scientists. It shows that this remains a dangerous experimental field with nothing routine. If and when men travel to Mars the standard of 100% safety and reliability will be impossible to achieve. It's all a gamble. You can get lost in space forever. Better take along a lot of toilet paper.

  • rate this

    Comment number 34.

    since we are generously allowed some lattitude:-

    on the matter of "space junk" do we know how long it will be before we inhabit a ringed planet?

    also, objects in space are lit by bright sunlight or in deep shadow, except for earthshine so it might require a good technique to obtain a decent photograph of the whole.

  • rate this

    Comment number 33.

    best not to go around looking up

    it will needlessly worry you unnecesarily

    its 200KG of russian junk

    ok thats a lot of russian junk falling on your head

    but i worked out the chances of it hitting you

    ten trillion to the power 2.3 million to 1

    so absolutely no need to worry !

  • rate this

    Comment number 32.


    Why is that falling spacecraft emitting light seen by Telescopes?."

    It isn't emitting light.

    "Is it the Sun light reflection from falling Spacecraft?"


  • rate this

    Comment number 31.

    Please tell me why I can no longer watch these video clips or the weather video forecast????????????????????????????????????????????

  • rate this

    Comment number 30.

    @Bill @xpdnc. As I understand it the drag decreases the kinetic energy of the satellite, by decreasing the size of the orbit, i.e. reducing the orbital height, but the speed actually increases. But when I said the descent would accelerate I meant simply that the perigee number would start to drop more rapidly. Anyone else, please weigh in. @RuRight. I need a new calendar! Fixed. Indebted.

  • rate this

    Comment number 29.

    I wonder, is it possible to fire a laser beam to the solar panels so the probe can get enough energy to communicate with the control center and be commanded to turn to the sun to be fully restored?
    If a person with a relatively cheap equipment could perform that tracking a government agency could do the same to fire a laser to the probe?
    Is this a silly idea or possible? Anyone knows?

  • rate this

    Comment number 28.

    I hope the NASA Mars probe is successful. Interested in a neat experiment check out NASA's Grail B mission-that measured gravity
    And no I am not a booster (pun intended) for NSA

  • rate this

    Comment number 27.

    Martians shot it down. Hell-bent on repelling invasion - what's wrong with them??!!

  • rate this

    Comment number 26.

    "At the moment, the projections are very uncertain. They are clustering around Saturday 15 January (GMT) and Sunday 16 January."

    In the year 2012, Saturday is January 14th!

  • rate this

    Comment number 25.

    How sad for the failure of this mission. However, as of these failures, just look at what we have achieved in the recent decades as a species. We have photographed 13 billion years in time, put man on the moon, have space probes in the far reaches of our solar system, sent vehicles to mars and learned so much from various other projects. Humans are far more successful in space than here on earth!

  • rate this

    Comment number 24.

    no no NO!!!....we won't watch videos or support STUPID SITES THAT REQUIRE YOU TO WATCH A 30 SECOND OR LONGER AD TO WATCH A VIDEO!!!!!.....15 SECONDS MAX!!!!.....GET ON BOARD WITH THE MOVEMENT!!!!!

  • rate this

    Comment number 23.

    Why is that falling spacecraft emitting light seen by Telescopes?.

    Is it the Sun light reflection from falling Spacecraft?.

    It didn't even enter the earths atmosphere to ignite through friction to emit light through burning?.

    The picture looks same like seen from failed probe couple of weeks before!.

  • rate this

    Comment number 22.

    "future modelling efforts can be finessed"

    The word is "improved". Please, can we have less of this ridiculous office talk in BBC articles - especially from a science correspondent.

  • rate this

    Comment number 21.

    I feel very sad for the Russian teams that spent so much time and effort designing, building and launching this craft. I wish them all the best for the future.

  • rate this

    Comment number 20.

    this is all so very sad but great photography.
    when the americans had this sort of trouble they recovered the sattelite. could the russians not have taken a quick look on the way to or from the iss?

    there are too many of these mars incidents for it to be a coincidence.

    earthlings be warned: "howling day" is soon!

  • rate this

    Comment number 19.

    Sad to see this mission fail. I wonder how many more will take place as the role of the private sector in science funding (i.e. product design) increases, as the US and UK govt. want. Answer to Fermi's Paradox? We're not alone, but all the other civilisations in the galaxy are capitalists... Thank goodness for the Chinese interest. It should spur a new space-race driven by pride not profit.


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