Phobos-Grunt’s Mysterious Thruster Activation: A Function of Safe Mode or Just Good Luck?


Editor’s note: Dr. David Warmflash, principal science lead for the US team from the LIFE experiment on board the Phobos-Grunt spacecraft, provides an update for Universe Today on the likelihood of saving the mission.

The Phobos-Grunt probe is still stuck in orbit around Earth. However, periodically the spacecraft experiences a mysterious slight boost in its orbit.  Following the first episode where this occurred, commentators speculated as to the cause.  The activation of the spacecraft’s thrusters – the small engines that are designed to steer the craft and make small adjustments  — was an obvious answer.

Is spacecraft trying to save itself?

The spacecraft is not responding to any communications, and engineers at the Russian Space Agency Roscosmos have decided that the craft had reverted to a safe mode after the engine of the Fregat rocket stage that was to propel her from a low to a higher orbit around Earth failed to ignite. While in safe mode, the craft had oriented herself to the Sun, using the thrusters to adjust her roll, pitch, and yaw. But to change the parameters of the orbit, she’d need to accelerate, so there was speculation that the needed thrust had come from leaks and venting of gases in a direction favorable to increased orbital stability.

After a second episode during which the altitude increased again, according to Ria Novosti editor-columnist of the journal “News of Cosmonautics” Igor Lisov has reported that a source in the space industry had explained that the probe “Corrects her orbit” every now and then.

Corrects her orbit? Does this mean that the probe knows where she is?

Probably not.

With information coming from Roscosmos being so scarce, reporting on the mission that began was launched on November 9, 2011 has depended on a few official statements from the agency, augmented by speculation from various space experts. Being in safe mode, Grunt simply is waiting for instructions –instructions that controllers are having difficulty delivering, because initial communication was not supposed to take place with the probe at such a low orbit.

If Grunt’s safe mode includes a program that fires thrusters every so often to keep the craft from entering the atmosphere in the event of a malfunction just after reaching low Earth orbit, no statements from Roscosmos have mentioned it, thus far. Whatever the reason, if it continues to occur, we can expect that the predicted date of atmospheric entry will be moved back again, just as it was moved from late December/early November to mid-January after the first orbital correction episode.

The Planetary Society’s Living Interplanetary Flight Experiment (LIFE) capsule, on board the Phobos-Grunt spacecraft. Credit:The Planetary Society

What might this mean for the mission? First of all, perhaps it could buy more time for controllers to establish communication –although Roscosmos has stated that December is the limit for correcting the problem, despite the fact that the probe will be in space at least until mid January. The second thing it could do would be to keep the Planetary Society’s LIFE experiment in space a little longer, which would have benefits only if the Grunt return capsule containing the LIFE biomodule separates from the rest of the craft and makes the reentry and landing that it was designed to do at the end of the flight. This possibility and the potential scientific value is discussed in my previous update, Might the LIFE Experiment be Recovered?

As for the question of why a craft that merely is supposed to find the Sun while in safe mode fires thrusters in a direction that improves the orbit, perhaps it is just good luck, or perhaps it really is part of the safe mode. Until Roscosmos provides more information of what may have caused this, the reason for the orbital correction remains a mystery.

36 Replies to “Phobos-Grunt’s Mysterious Thruster Activation: A Function of Safe Mode or Just Good Luck?”

  1. I am actually wondering if they just can reboot the thing and it goes off for a very successfull mission.

      1. Due to the low orbit the spacecraft can only be reached for up to 7 minutes per pass from any groundstation. That is very little time to setup communication,analyse any issues and sent appropiate commands.

      2. Wondering if any one of the many satellites above it might be used to relay commands. One of their (or ours?) mill sats should be able to tune it’s transponder. Just a layman’s shot in the dark.

      3. My guess – and it is just a guess – is that the receiver is designed to point at Earth from a very long distance away, so any signal coming from any point on Earth will be received (since the whole of Earth will be in line of sight of the receiver)

        If the probe is too close, the line-of-sight of the receiver will only point at a relatively small portion of Earth (or empty space), and nobody knows what portion it is (and it may be constantly changing as the probe drifts around), so any signals being sent won’t be received.

        I guess the receiver is a bit like looking through a cardboard tube – stand far enough away from a sign and you can read all of it, stand too close and you can only look at one letter at a time.

        Can anyone confirm if my thinking is along the right lines?

    1. I wish Roskosmos was a little more transparent about the situation. They should be asking NASA for help to recover this important project. If they stay hidden and can’t fix it, they’ll be in a lot of hot water over all the failures they’ve had in the past couple years

      1. I too wonder if the closed-mouth Russian Space Agency is not hurting its chances of finding, discovering a mission-saving solution by being so opaque about the details of what is going on behind the scenes. Depending on the actual condition of the mute spacecraft itself, and the ongoing range of efforts to establish commanding communication, there just might be someone at NASA, ESA, or elsewhere, who could possibly have an answer, or an idea that could lead to a resolution. The more expert, experienced minds informed, the closer to solving the problem, could be.

  2. Russian space industry is made in barracks. They need desparte foundations but as with NASA they got cut , but rise money on military and social polices. The thing is that the system of money is out of date. We need something else, but here is no point to discuss it.

    I hope myself that i will make it and if it doesnt they have made a catch anyway. Fregat has to be modified this is a lesson for them. Expensive but still.

    As always heads will fall in Russia or not because it does not give Putin and Co. any money or sucsess to rise money they will spend something else than space exploration.

    1. the system of money is out of date

      Not from observations, the market works better than ever for redistributing resources. Very few nations are stuck in a rut – Afghanistan and one or two African nations, claims Hans Rosling.

      It is like democracy, it is not perfect but the alternatives are worse. Or as we note in science, you can’t make your theory valid by trying to invalidate other theories.

      1. “It is like democracy, it is not perfect but the alternatives are worse”.
        I hear this often from many.
        Just because you have not heard about it does not mean there are no other systems which are running much better than so called western “democracy”.
        In Indonesia people call the western “democracy” as “Demo-crazy”.
        The system has not stopped corruption or inefficiency. Think about the money spend on elections. Indonesia tried to implement regional autonomy. That is similar to, the “Jamariyah” system of Libya and “Panjayat” system of India. In fact it similar to “state independence” originally defined in the US Constitution.
        These are systems which gave power to the people. While US followed its constitution, USA was number one, in economic growth and increasing wealth of its people. Just as it was happening in Libya and India. You cannot know the real wealth of Indians by reading western papers. There are millions of poor people there but also Billions who are living happy and wealthy. even a poor man with wooden house will have some Gold in his pocket to the envy of western Bankers. Don’t compare western countries build with Latin, Chinese and other slave labors with real development achieved by these so called poor countries.

      2. I have “heard” about those by way of statistics. I’m not the one making these claims, Rosling is using world statistics. (Watch his TED talks, say.)

        According to those statistics democracy, social medicine and the current free market boost has meant less poverty et cetera for more people than ever before. It is also very easy to check his claims, you can use his Gapminder web interface to do it yourself. The data is out there.

        so called poor countries

        That points to your problem right there. Rosling points out, and again you can check this, that there is no artificial bimodal (double peaked) distribution in economies separating “rich/developed” with “poor/developing” nations any longer. (It went away in the 60-70’s, IIRC.)

        If you look at the data instead of doing political “just so” analysis attempts, you will see that we are all one world economically and more or less democratically now.

    2. You write as if you know something. Do you know that Putin and Company is accumulating cash? where? in American or British Banks? You think so? or know so?
      Don’t be an idiot. The moment Putin does that he will be destroyed and all his money confiscated by Western Bankers through their puppet American and Europeans Governments. Where have you been living while western countries swindled billions from Iraq and Libya?
      If I were a Russian Leader I would advise spending every Rubles on defense readiness now which is in shambles now thanks to Yeltsin’s trust of western advise. The example is Qaddafi who also cancelled many defense contracts with Russia and embarked on investing billions in western Banks. They are now confiscated and plan is to pretend to hand over to rebels while actually getting paid for the bombing water and electricity supplies. wake up.
      Thank God, you are not a leader of Russia. or my country.

  3. This is such a sad story…millions of dollars and thousands of man-hours put into the designing, building and launching of this machine. A major setback for the Russian space efforts, to say the least. I am still hopeful they can somehow salvage this craft, but it looks like even if they can reboot the software, the flight mechanics would not allow the craft to reach Mars anyway, sooooo…..bye-bye Phobos-Grunt. 🙁

    1. Considering that a large part of the price tag goes into global design, component design, validation of concepts, software implementation, tests, and mission control development (eg ground-based hardware and teams), they could very well rebuild TWO copies of the same exact probe within 2 years and send it during the next launch window in 2014, for perhaps 2/3 of the original price; over the next 2 years, they would have to keep the whole science team busy and on the payroll, but it’s not like they’re out of cash anymore!

      Remember the venus exploration era (Venera)? They were sending a pair of probes every 2 years or so to Venus, and were not deterred by occasional failure. In fact, Mars and Venus are perfect targets for a “low cost, high redundency, run-of-the-mill” exploration program. Instead of sending costly monolithic missions, we should be able to send a constant flow of generic probes with varied plug-in modules and instruments, and make the successful probes work together so that they’re more than the sum of their individual instruments.

    1. They don’t want that thing any where near the ISS, or anything else we want to keep whole. I understand it as being akin to picking up a dud firecracker in your bare hand. You just don’t know if the minute you get close is the minute it will wake up and fire those rockets. Maybe we could try to relay signals to it from the ISS? Might be even better to just wait for it to reenter. It is sad though, I was looking forward to them finding that monolith full of stars on Phobos.

  4. Russian Space Agency is always working on shoe-string budget, compared to western finance standards. Russians put tourist in space for US$20 million to the envy of western nations.
    But by Russian living standards, Russian Space Agency is very well funded. So no need to cry over low budget etc.
    Talking about the article, I feel the mystery surrounding thruster activity lies in the electronic controls. Russians have been doing well in space explorations better until joining western countries in the use of electronic equipment. While before that Russian HMI were mostly using electrical switches and they were reliable and very efficient too. The western electronics provide much wider options for implementation but are prone to many hazards. including vibrations and electro magnetic influences. I would advice looking into that.

    1. “Russians have been doing well in space explorations better until joining western countries in the use of electronic equipment.”

      I hope that you are not going to blame Western world for all Russian failures. Even an idiot like myself could say what is right and wrong, a smart person like you should be more careful when saying such thing.

    2. Remember the Soviet-era Phobos 1 & 2 missions? Both probes were lost due to various computer design errors. First probe was lost because a technician sent a command with a wrong bit, which reactivated the hardcoded pre-launch test sequence in PROM memory; it sent the probe tumbling lifelessly through space, and it was never recovered.

      The second probe was lost because 2 of its 3 onboard computers had failed; normally it should have been able to keep working, but some overconfident programmers had implemented a quorum algorithm to reinforce redundency in data and programs. But he had forgotten to implement safeguards to make a single onboard computer work alone despite the impossibility to check for quorum. So a perfectly working probe got stuck into a cycle of never-ending “check and wait” loops and drained its batteries.

    1. Sure, send a 500 million dollar shuttle flight to save a 160 million dollar probe. That makes all kinds of sense.

  5. Perhaps Phobos-Grunt can be kept on Earth orbit for the next Mars transfer orbit window to open in about two years (assuming that it misses this window but doesn’t re-enter)? Probably the Fregat upper stage is not designed for such a long hiatus in space but maybe it would work anyway?
    Or are there slower trajectories to Mars that could be used instead of the planned one?

    1. The current orbit has too much drag, which is why the probe will eventually reenter. There isn’t enough fuel to stave that off, at least if you want to go to Mars later.

      And since there is no contact with the probe as of yet, it is a moot option. If they can contact it and at least move it to the larger 2nd parking orbit ellipse you will buy time.

    1. Probably the E.T’s are about 25,000 years ahead of earth people, be it American or Russian, its a no contest, incident with E.T.’s versus the Planet Earth (be it the best Scientists in China, Russia or U.S.A., or even Israel). The E.T.s would flatten the Earth Planet with their best scientists, we’ve got to offer.

  6. It seems that at such a low orbit, the probe’s antenna is blocked from the ground. Could the probe receive a signal from orbit instead of one from the ground? — maybe from the ISS or an orbiting capsule?

  7. The antenna was placed too close to a fuel tank, and in such a low orbit, the tank is blocking signals meant to reach the antenna.

  8. And you see why Russia and China are so resentful of us… we send projects into space that get there, and work. They can barely make it up.

  9. If the Phobos-Grunt are sending command to thrusters, the MDU, derivate of Fregat, ignites the small thrusters that pre-accelerates the spacecraft to push the combustible to the great motors might boost the orbit. Only that the main engines not ignites.

    If that is true, Then the spacecraft is doomed to remain in orbit, the Phobos-Grunt recieves the signals of the ground and then start the sequence of ignite the main engines, but only the small thrusters are functional.


  10. Have the chinese made their spacecraft able to dock with the international ss. Did the chinese not realise that blowing up one of their defunct satelite would produce dangerous items in space. How irresponsible

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